Information transfer by vector spin chirality in finite magnetic chains

Vector spin chirality is one of the fundamental characteristics of complex magnets. For a one-dimensional spin-spiral state it can be interpreted as the handedness, or rotational sense of the spiral. Here, using spin-polarized scanning tunneling microscopy, we demonstrate the occurrence of an atomic-scale spin-spiral in finite individual bi-atomic Fe chains on the (5x1)-Ir(001) surface. We show that the broken inversion symmetry at the surface promotes one direction of the vector spin chirality, leading to a unique rotational sense of the spiral in all chains. Correspondingly, changes in the spin direction of one chain end can be probed tens of nanometers away, suggesting a new way of transmitting information about the state of magnetic objects on the nanoscale.Comment: accepted by Physical Review Letter

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In der vorliegenden Diplomarbeit werden nachstehende Fragen zu Gottfrieds Tristan und Wolframs Parzival thematisiert: Trauer und Sorge an Wendepunkten des Lebens der Helden. Problematik der Verborgenheit und Dechiffrierung unter besonderer Berücksichtigung der Tristanliebe. Identität als Frage von Herkunft und Lebensweg. Problematik des Erkennens und Verkennens unter dem Aspekt der Verfeinerung der Kulturauffassung durch Gottfried. Erkennen und Verkennen der Hauptgestalten und ihres Telos von den Wahrnehmungsstandpunkten der Figuren, des Autors und des Publikums. Problematik von Lernprozessen. Problematik von Erkennen und Verkennen im Zusammenhang mit Recht, Unrecht, Schuld und Schuldeinsicht. Meine Arbeit wurde im Frühjahr und Sommer 2009 in Wien verfaßt. Sie nimmt vom Ausgangspunkt von Motiven des Weinens im Tristan und im Parzivâl die Thematik des Sorgens und Trauerns auf. Von dort richtet sie ihren Fokus schließlich auf die damit verbundenen Vorgänge des Erkennens beziehungsweise des Verkennens. Sie führt damit in jene Schichten des Tristan, in denen die Substanz von Krise und Bewährung, von Chance und Risiko, von Gewinn und Verlust liegt, eine Substanz, die in jedem großen Werk der Weltliteratur angesiedelt ist. Es ist allgemein menschlich, aus einer solchen Schicht heraus die Welt wahrzunehmen und sie zum eigenen Gewinn zu interpretieren, indem man die Organe der Wahrnehmung schärft. Jedes Werk der Kunst wird damit zu einem Fenster in die wahre und wirkliche Welt. Kunstinterpretation ist deshalb auch Interpretation von Lebensvorgängen und ist zugleich Zugewinn von Wissen und Verständnis. Kunstinterpretation unter einem solchen Aspekt zu üben, war Ziel dieser Arbeit

Micropatterning of Plasma Membrane Proteins to Analyze Raft Localization in Living Cells

International audienc

Long-term recurrence rate in anterior shoulder instability after Bankart repair based on the on- and off-track concept

BACKGROUND Since its first proposal, the concept of on- and off-track lesions in anterior shoulder instability has gained clinical relevance as a tool to predict the failure rate of arthroscopic Bankart repair. Current literature only reports either short-term follow-up or long-term results of small sample sizes. The aim of this study was to provide a long-term evaluation of recurrent instability following arthroscopic Bankart repair in a large cohort using the on-track vs. off-track concept as a predictor for failure. METHODS We retrospectively analyzed 271 patients who underwent primary arthroscopic Bankart repair for anterior shoulder instability between 1998 and 2007. All patients with a minimum follow-up of 78 months and a preoperative computed tomographic (CT) or magnetic resonance imaging (MRI) scan were included into the study. Preoperative CT and/or MRI scans were used to determine the glenoid track and width of Hill-Sachs lesion. Recurrence of instability was defined as presence of instability symptoms (dislocation, subluxation, and/or apprehension) or revision surgery (stabilization procedure) and was assessed as the primary outcome parameter. RESULTS The glenoid track of 163 shoulders was assessed (female n = 51, male n = 112) with a mean follow-up of 124 months (99.4-145.6, standard deviation = 2.5) and a mean age of 24 years (20-34.). An off-track Hill-Sachs lesion was found in 77 cases (47%), and in 86 cases (53 %) it was on-track. The rate of recurrent instability in the off-track group was 74% (n = 57) compared with 27% (n = 23) in the on-track group (P < .001). The overall rate of revision surgery due to instability was 29% (n = 48) after a mean time of 50.9 months (±42.8) following Bankart repair. The rate of revision surgery in the off-track group was 48% (n = 37) after a mean of 53.5 months (±42.0) vs. 13% (n = 11) after 42.3 months (±46.3) in the on-track group (P < .001). CONCLUSION This study shows that the on- and off-track concept helps to distinguish patients for whom an isolated arthroscopic Bankart repair yields long-term benefits. Because of the high rate of recurrent instability in the off-track group, an off-track lesion should be treated surgically in such a way that the off-track lesion is converted into an on-track lesion

Nanoparticle detection in an open-access silicon microcavity

We report on the detection of free nanoparticles in a micromachined, open-access Fabry-P\'erot microcavity. With a mirror separation of $130\,\mu$m, a radius of curvature of $1.3\,$mm, and a beam waist of $12\,\mu$m, the mode volume of our symmetric infrared cavity is smaller than $15\,$pL. The small beam waist, together with a finesse exceeding 34,000, enables the detection of nano-scale dielectric particles in high vacuum. This device allows monitoring of the motion of individual $150\,$nm radius silica nanospheres in real time. We observe strong coupling between the particles and the cavity field, a precondition for optomechanical control. We discuss the prospects for optical cooling and detection of dielectric particles smaller than $10\,$nm in radius and $1\times10^7\,$amu in mass.Comment: 4 pages, 3 figure

Peri-operative chemotherapy for the treatment of resectable liver metastases from colorectal cancer: A systematic review and meta-analysis of randomized trials

<p>Abstract</p> <p>Background</p> <p>The role of peri-operative chemotherapy in patients with resected stage IV colorectal cancer (CRC) remains to be defined. This study was aimed at evaluating the effectiveness of peri-operative chemotherapy in patients with resected stage IV CRC by performing a meta-analysis of relevant trials.</p> <p>Methods</p> <p>We performed a literature search to identify trials comparing patients with stage IV CRC receiving peri-operative chemotherapy and surgery with patients undergoing surgery alone. The hazard ratio (HR) was estimated to assess any survival advantage of peri-operative chemotherapy.</p> <p>Results</p> <p>Eight trials conducted on a total of 1174 patients were identified by a literature search. In these trials, HR estimates suggested that peri-operative chemotherapy yielded no survival advantage over surgery alone (HR, 0.94; 95%CI, 0.8-1.10; <it>p </it>= 0.43). In a subset analysis on intra-arterial chemotherapy alone, no survival benefit was evident (HR, 1.0; 95% CI, 0.84-1.21; <it>p </it>= 0.96; I²= 30%), whereas in the trials involving systemic chemotherapy, the difference between the groups approached statistical significance (HR, 0.74; 95% CI, 0.53-1.04; <it>p </it>= 0.08; I²= 0%). Both peri-operative treatment groups had a significant recurrence-free survival benefit (HR, 0.78; 95% CI, 0.65-0.95; <it>P </it>= 0.01 for hepatic arterial infusion; and HR, 0.75; 95% CI, 0.62-0.91; <it>p </it>= 0.003 for systemic therapy). The toxicities of chemotherapy were acceptable in most trials.</p> <p>Conclusions</p> <p>This is the first meta-analysis demonstrating the importance of peri-operative chemotherapy in the treatment of resected stage IV CRC. Although the results must be carefully interpreted because of some limitations, critical issues were identified that must be resolved by future studies.</p

Stitch positioning influences the suture hold in supraspinatus tendon repair

Purpose: This study was designed to compare the pull-out strength of simple suture stitches in human supraspinatus tendons with respect to the position of the rotator cable. Methods: Fifty-four tests were performed on 6 intact, human supraspinatus tendons, to assess the cutout strength of a simple suture configuration in different positions; medial to, lateral to, or within the rotator cable. Tendon thickness was measured and correlated for each positioned suture. Results: Suture positioning lateral to or in the rotator cable showed significantly lower suture retention properties compared with positioning the suture medial to the cable (p=0.002). In all tested specimens, the central stitch in the row medial to the rotator cable provided the optimum retention properties (mean: 191N; SD:±44; p<0.01), even after correcting for tendon thickness. Conclusion: This study shows that it is desirable to identify the rotator cable and to pass sutures just medial to it, close to the middle of the tendon, which provided highest possible suture retention propertie

Clinical and laboratory considerations: determining an antibody-based composite correlate of risk for reinfection with SARS-CoV-2 or severe COVID-19

Much of the global population now has some level of adaptive immunity to SARS-CoV-2 induced by exposure to the virus (natural infection), vaccination, or a combination of both (hybrid immunity). Key questions that subsequently arise relate to the duration and the level of protection an individual might expect based on their infection and vaccination history. A multi-component composite correlate of risk (CoR) could inform individuals and stakeholders about protection and aid decision making. This perspective evaluates the various elements that need to be accommodated in the development of an antibody-based composite CoR for reinfection with SARS-CoV-2 or development of severe COVID-19, including variation in exposure dose, transmission route, viral genetic variation, patient factors, and vaccination status. We provide an overview of antibody dynamics to aid exploration of the specifics of SARS-CoV-2 antibody testing. We further discuss anti-SARS-CoV-2 immunoassays, sample matrices, testing formats, frequency of sampling and the optimal time point for such sampling. While the development of a composite CoR is challenging, we provide our recommendations for each of these key areas and highlight areas that require further work to be undertaken

Surgical knot tightening: how much pull is necessary?

Purpose: High-strength sutures allow tightening of a suture knot beyond the strength of the surgeon, possibly inflicting skin damage through the gloves. This study was undertaken to evaluate whether such effort is useful and how much tensioning on a surgical knot is necessary. Methods: Three different suture materials were tested: No. 2 Vicryl™, FibreWire™, and PDS™. First, the force spontaneously applied on sutures during experimental knot tightening ("tying load”) was measured in fifteen experienced surgeons. Second, with each suture material, surgical square knots were tied with increasing, standardized loads (range 0.5-50N) using a custom-made apparatus. Thereby, knot seating after tying was evaluated, and by loading the knots to failure, evaluation for failure mode and failure load was performed. Results: FibreWire™ 5-throw square knots always failed by complete slipping of all knots (resolving), independent on the tying load. A nonlinear decrease of knot slippage and increased failure load were seen with increasing tying loads for all sutures. Major differences were seen between 0.5 and 10 N for FibreWire™ (slippage: 25mm) and PDS™ (99.6mm), whereas Vicryl™ showed major differences (22.7mm) between 0.5 and 2N. Increasing the tying load from 10 to 50N decreased the mean knot slippage from 12 (FibreWire™, ±2.6 SD), 9 (PDS™, ±1.8 SD) and 8 (Vicryl™, ±1.3 SD) mm to 6 (±2.9 SD), 3 (±1.5 SD) and 4mm (±0.9 SD), respectively. Conclusion: Slippage and self-seating of the knots under load is unavoidable even with highest tying loads. Relatively minor but possibly important differences can be seen for tying loads exceeding 2N (Vicryl™) and 10N (PDS™ and FibreWire™) for failure load and knot slippage. But also with a tying load of 50N, a minimal slippage of approximately 3mm seems unavoidable for all suture types. However, it is important to state that intense tightening does not prevent knot resolution and is only necessary in clinical situations that demand very tight sutures. Numbers and proper appliance of throws are more relevant than tying strength to reach the maximum failure load