1,320 research outputs found

    High-magnetic field phase diagram and failure of magnetic Gr\"uneisen scaling in LiFePO4_4

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    We report the magnetic phase diagram of single-crystalline LiFePO4_4 in magnetic fields up to 58~T and present a detailed study of magneto-elastic coupling by means of high-resolution capacitance dilatometry. Large anomalies at \tn\ in the thermal expansion coefficient α\alpha imply pronounced magneto-elastic coupling. Quantitative analysis yields the magnetic Gr\"uneisen parameter γmag=6.7(5)107\gamma_{\rm mag}=6.7(5)\cdot 10^{-7}~mol/J. The positive hydrostatic pressure dependence dTN/dp=1.46(11)dT_{\rm N}/dp = 1.46(11)~K/GPa is dominated by uniaxial effects along the aa-axis. Failure of Gr\"uneisen scaling below 40\approx 40~K, i.e., below the peak temperature in the magneto-electric coupling coefficient [\onlinecite{toft2015anomalous}], implies several competing degrees of freedom and indicates relevance of recently observed hybrid excitations~[\onlinecite{yiu2017hybrid}]. A broad and strongly magnetic-field-dependent anomaly in α\alpha in this temperature regime highlight the relevance of structure changes. Upon application of magnetic fields BbB||b-axis, a pronounced jump in the magnetisation implies spin-reorientation at BSF=32B_{\rm SF} = 32~T as well as a precursing phase at 29~T and T=1.5T=1.5~K. In a two-sublattice mean-field model, the saturation field Bsat,b=64(2)B_{\rm sat,b} = 64(2)~T enables the determination of the effective antiferromagnetic exchange interaction Jaf=2.68(5)J_{\rm af} = 2.68(5)~meV as well as the anisotropies Db=0.53(4)D_{\rm b} = -0.53(4)~meV and Dc=0.44(8)D_{\rm c} = 0.44(8)~meV

    Intoxicated eyewitnesses:the effect of a fully balanced placebo design on event memory and metacognitive control

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    Few studies have examined the impact of alcohol on metacognition for witnessed events. We used a 2x2 balanced placebo design, where mock-witnesses expected and drank alcohol, did not expect but drank alcohol, did not expect nor drank alcohol, or expected but did not drink alcohol. Participants watched a mock-crime in a bar-lab, followed by free recall and a cued-recall test with or without the option to reply ‘don’t know’ (DK). Intoxicated mock-witnesses’ free recall was less complete but not less accurate. During cued-recall, alcohol led to lower accuracy, and reverse placebo participants gave more erroneous and fewer correct responses. Permitting and clarifying DK responses was associated with fewer errors and more correct responses for sober individuals; and intoxicated witnesses were less likely to opt out of erroneous responding to unanswerable questions. Our findings highlight the practical and theoretical importance of examining pharmacological effects of alcohol and expectancies in real-life settings

    On the Shape of Liquid Metal Droplets in Electromagnetic Levitation Experiments

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    We present calculations and measurements on the shape of liquid metal droplets in electromagnetic levitation experiments. A normal stress balance model was developed to predict the shapes of liquid metal droplets that will be obtained in a microgravity experiment to measure the viscosity and surface tension of undercooled metals. This model was tested by calculating the droplet shapes in containerless experiments conducted to determine the surface tension of liquid metals. Inconsistencies associated with the results of a previous paper are elucidated. The computational results of the mathematical model are compared with the results of ground-based experiments for two different metals. The importance of the ratio of electromagnetic skin depth-to-droplet radius to the accuracy of the mathematical model is discussed. A planned alternate approach to modeling the shape by consideration of the entire droplet rather than only the surface is presented. As an example of an application. the influence of the shape on the splitting of the surface oscillation modes of levitated liquid metal droplets is discussed

    Factors influencing life satisfaction in acute myeloid leukemia survivors following allogeneic stem cell transplantation: a cross-sectional study

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    Background: Allogeneic stem cell transplantation (alloSCT) is the preferred option of postremission therapy for high-risk patients suffering from acute myeloid leukemia (AML). Therefore, monitoring life satisfaction (LS) of long-term survivors following alloSCT is becoming increasingly important for oncologists. The aim of the study was to evaluate individual survivor priority of various general and health-related domains of life and their satisfaction with these domains. Furthermore, we investigated the impact of general and health-related LS on resilience, anxiety, depression and quality of life in AML survivors following alloSCT. Methods: Forty-one AML survivors (median age at time of assessment = 49.0 years) who had undergone alloSCT (median time since transplantation = 3.1 years) were enrolled in the study. Psychosocial parameters were assessed using the following instruments: FLZM (Questions on Life Satisfaction), EORTC QLQ-C30, HADS (Hospital Anxiety and Depression Scale) and the RS-25 (Resilience Scale-25 items). Correlation analyses were computed to reveal the associations between the different questionnaires. Results: Independence from help or care, well-regulated living conditions and financial security contributed positively to LS, whereas being off work due to health-reasons and dissatisfaction with physical aspects were negatively associated to the subjective feelings of overall satisfaction. Moreover, a high quality of life was strongly positively correlated with LS (Spearman’s rho general LS: 0.643 and health-related LS: 0.726, both p < 0.001). A high degree of resilience was also strongly positively correlated with better LS (general LS: 0.700, health-related LS: 0.675, both p < 0.001). Symptoms of anxiety and depression were associated with an impaired general LS (anxiety: −0.674, depression: −0.698, both p < 0.001). Conclusions: Our results indicate that LS should be considered an important key contributor to the survivors’ well-being following alloSCT. Thus, identifying protective psychological and physical factors that relieve stressors is of high importance in order to support long-term AML survivors with their special needs.<br

    Use of marginal organs in kidney transplantation for marginal recipients: too close to the margins of safety?

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    <p>Abstract</p> <p>Objective</p> <p>Due to organ shortage, average waiting time for a kidney in Germany is about 4 years after start of dialysis. Number of kidney grafts recovered can only be maintained by accepting older and expanded criteria donors. The aim of this study was to analyse the impact of donor and recipient risk on kidney long-term function.</p> <p>Methods</p> <p>All deceased kidney transplantations were considered. We retrospectively studied 332 patients between 2002 and 2006; divided in 4 groups reflecting donor and recipient risk.</p> <p>Results</p> <p>Non-marginal recipients were less likely to receive a marginal organ (69 of 207, 33%) as compared to marginal recipients, of whom two-thirds received a marginal organ (p < 0.0001). Graft function significantly differed between the groups, but detrimental effect of marginal recipient status on eGFR after 12 months (-6 ml/min/1.73 qm, 95% CI -2 to -9) was clearly smaller than the effect of marginal donor status (-10 ml/min/1.73 qm, 95% CI -7 to -14).</p> <p>Conclusions</p> <p>As we were able to show expanded criteria donor has a far bigger effect on long-term graft function than the "extra risk" recipient. Although there have been attempts to define groups of recipients who should be offered ECD kidneys primarily the discussion is still ongoing.</p

    Short- and Long-Term Results of Open Versus Laparoscopic Appendectomy

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    Clinical advantages of laparoscopic appendectomy have been shown in numerous trials and reviews. Most of these advantages are small and of limited clinical relevance, while laparoscopic operation costs are reported to be higher. The present study compares short- and long-term results of conventional appendectomy with or without diagnostic laparoscopy (OA), and laparoscopic appendectomy (LA). All adult patients who underwent appendectomy in our institution from 1995 to 2005 were included retrospectively. Patient data were retrieved from medical records, questionnaires sent by mail, and records of general practitioners. Primary outcome parameters were long-term complications, readmissions, and reinterventions (> 30 days postoperatively). Secondary outcome parameters were short-term complications, readmissions, and reinterventions (a parts per thousand currency sign30 days postoperatively). A total of 755 patients were included, 545 of whom underwent OA, with the remaining 210 undergoing LA. In the long term there were few complications noted, and there were no significant differences in complications between the two groups. Within 30 days postoperatively, LA was associated with a significantly higher incidence of abdominal abscesses with consequent diagnostic investigations, interventions, and readmissions. Although laparoscopic appendectomy is known to deliver clinical advantages, it is associated with a higher incidence of abdominal abscesses. Because the procedure is about to become the standard of care, future research must be directed at solving this issue. The expected lower incidence of incisional hernia and small bowel obstruction after laparoscopic appendectomy was not shown in the present stud

    PRE-MARKET CLINICAL EVALUATIONS OF INNOVATIVE HIGH-RISK MEDICAL DEVICES IN EUROPE

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    Objectives:High-quality clinical evidence is most often lacking when novel high-risk devices enter the European market. At the same time, a randomized controlled trial (RCT) is often initiated as a requirement for obtaining market access in the US. Should coverage in Europe be postponed until RCT data are available? We studied the premarket clinical evaluation of innovative high-risk medical devices in Europe compared with the US, and with medicines, where appropriate.Methods:The literature and regulatory documents were checked. Representatives from industry, Competent Authorities, Notified Bodies, Ethics Committees, and HTA agencies were consulted. We also discuss patient safety and the transparency of information.Results:In contrast to the US, there is no requirement in Europe to demonstrate the clinical efficacy of high-risk devices in the premarket phase. Patients in Europe can thus have earlier access to a potentially lifesaving device, but at the risk of insufficiently documented efficacy and safety. Variations in the stringency of clinical reviews, both at the level of Notified Bodies and Competent Authorities, do not guarantee patient safety. We tried to document the design of premarket trials in Europe and number of patients exposed, but failed as this information is not made public. Furthermore, the Helsinki Declaration is not followed with respect to the registration and publication of premarket trials.Conclusions:For innovative high-risk devices, new EU legislation should require the premarket demonstration of clinical efficacy and safety, using an RCT if possible, and a transparent clinical review, preferably centralized.</jats:p

    Reconstruction of the gastric passage by a side-to-side gastrogastrostomy after failed vertical-banded gastroplasty: a case report

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    INTRODUCTION: Vertical-banded gastroplasty, a technique that is commonly performed in the treatment of morbid obesity, represents a nonadjustable restrictive procedure which reduces the volume of the upper stomach by a vertical stapler line. In addition, a textile or silicone band restricts food passage through the stomach. CASE PRESENTATION: A 71-year-old woman presented with a severe gastric stenosis 11 years after vertical gastroplasty. We describe a side-to-side gastrogastrostomy as a safe surgical procedure to restore the physiological gastric passage after failed vertical-banded gastroplasty. CONCLUSION: Occasionally, restrictive procedures for morbid obesity cannot be converted into an alternative bariatric procedure to maintain weight control. This report demonstrates that a side-to-side gastrogastrostomy is a feasible and safe procedure
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