500 research outputs found

    Cavity QED in superconducting circuits: susceptibility at elevated temperatures

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    We study the properties of superconducting electrical circuits, realizing cavity QED. In particular we explore the limit of strong coupling, low dissipation, and elevated temperatures relevant for current and future experiments. We concentrate on the cavity susceptibility as it can be directly experimentally addressed, i.e., as the impedance or the reflection coefficient of the cavity. To this end we investigate the dissipative Jaynes-Cummings model in the strong coupling regime at high temperatures. The dynamics is investigated within the Bloch-Redfield formalism. At low temperatures, when only the few lowest levels are occupied the susceptibility can be presented as a sum of contributions from independent level-to-level transitions. This corresponds to the secular (random phase) approximation in the Bloch-Redfield formalism. At temperatures comparable to and higher than the oscillator frequency, many transitions become important and a multiple-peak structure appears. We show that in this regime the secular approximation breaks down, as soon as the peaks start to overlap. In other words, the susceptibility is no longer a sum of contributions from independent transitions. We treat the dynamics of the system numerically by exact diagonalization of the Hamiltonian of the qubit plus up to 200 states of the oscillator. We compare the results obtained with and without the secular approximation and find a qualitative discrepancy already at moderate temperatures.Comment: 7 pages, 6 figure

    Multi-scale characterisation of the 3D microstructure of a thermally-shocked bulk metallic glass matrix composite

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    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods

    Funktionskapazität und psychosomatische Komorbiditäten bei Patienten mit chronischen Schmerzen - Evaluation einer Schmerzsprechstunde

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    Im Rahmen der Studie wurden 241 Patienten, die im Zeitraum von Februar 2006 bis Mai 2009 die Psychosomatische Schmerzambulanz in Tübingen besuchten, Fragebögen vorgelegt. Neben den Fragebögen wurde ein klinisch-diagnostisches Interview durch einen erfahrenen Therapeuten (Arzt oder Psychologe) durchgeführt. Der einzelne Patient erhält jeweils einen Fragebogen zu deskriptiven Fragestellungen, den PHQ-D zur Diagnose der häufigsten psychischen Erkrankungen, den FFBH-R zur alltagsnahen Diagnostik von Funktionsbeeinträchtigung von Rückenschmerzen, den SF-36 zur Beurteilung des allgemeinen Gesundheitsstatus und den PSQ zur Stressbeurteilung. Die Stichprobe beinhaltet Patienten von 17 bis 84 Jahre (mittleres Alter 46,2 J). Der Großteil der Patienten (54,6%) ist verheiratet und lebt mit dem Partner zusammen. Die größte Subgruppe stellen Patienten mit Haupt- und Realschulabschluss (kumulativ 54%), außerdem Angestellte, dar. Hauptzuweiser der Patienten sind die Allgemeinmediziner. 75% der Patienten zeigen eine somatoforme Schmerzstörung, 13,9% leiden an einer Angststörung. Die Patienten geben im Mittel eine subjektive Schmerzstärke von 6,79 auf der visuellen Analogskala an, 81,45 % der Patienten an verschiedenen Lokalisationen. Bei 50,5% der Patienten mit mehrfachen Arztbesuchen in den letzten vier Wochen liegt ein großes Inanspruchnahmeverhalten medizinischer Leistungen vor. Es konnte gezeigt werden, dass Patienten mit weiblichem Geschlecht, Verwitwete, Patienten mit geringerer Funktionskapazität im FFBH-R und höherem Schweregrad einer Depression jeweils höhere Werte auf der visuellen Analogskala zeigen. Gerade die Funktionskapazität zeigte sich als großer Einflussfaktor auf das Schmerzerleben, am ehesten in Form eines Markers der erlebten Lebensqualität. Als erklärende Faktoren für die Varianz der Funktionskapazität konnten das Alter und die Depressivität gezeigt werden. Diese erklären 14% der Varianz der Funktionskapazität im gerechneten Regressionsmodell. Das Alter stellt einen unbeeinflussbaren Faktor dar. Die Depression allerdings einen einfach zu diagnostizierenden und außerdem durch Zuführung einer adäquaten Therapie, gut behandelbaren Faktor. Die Diagnose und vor allem die Behandlung der Komorbidität Depression zur Vermeidung einer Chronifizierung der Schmerzerkrankung stellt eine Hauptforderung und Quintessenz der vorliegenden Arbeit dar.

    Liver transplantation in primary biliary cirrhosis: Risk assessment and 11-year follow-up

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    Background/Aims: Liver transplantation (LTx) is the only established treatment in patients with end-stage primary biliary cirrhosis (PBC). Although short-term survival after LTx in this group of patients is usually good, few data exist on the long-term survival. The optimal timing of transplantation is difficult. Thus, the aims of this study were to assess the long-term survival of patients with PBC after LTx and to identify potential predictive factors for a positive outcome. Methods: Survival of 28 patients with PBC who underwent LTx between 1985 and July 1999 in a single center was studied by Kaplan-Meier analysis and was compared to predicted survival without LTx using established prognostic models for PBC, the Mayo and European risk scores. Potential prognostic parameters obtained before LTx were tested for correlation to survival. Rates of bone fractures as markers of hepatic osteodystrophy were compared before and after LTx. Results: Median follow-up after LTx was 90 months with a maximum of 140 months. Actuarial survival of patients with PBC was 89% after 1, 5, and 10 years and was significantly better than estimated survival without LTx after 1-7 years as calculated by the Mayo and European risk scores. Of several parameters tested, only serum bilirubin and the prognostic scores, but no other liver function tests obtained immediately prior to transplantation were significantly correlated with survival after LTx. The duration of intensive care after LTx was not associated with any parameters obtained before LTx. Bone fractures were diagnosed in 43% of patients of whom the vast majority were osteopenic before LTx as determined by osteodensitometry. Conclusion: Longterm survival of a well-defined group of patients with PBC was excellent after LTx and was inversely correlated with preoperative serum bilirubin levels as well as Mayo and European risk scores. Copyright (C) 2000 S. Karger AG. Basel

    Identification of factors influencing insertion characteristics of cochlear implant electrode carriers

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    Insertion studies in artificial cochlea models (aCM) are used for the analysis of insertion characteristics of different cochlear implant electrode carrier (EC) designs by measuring insertion forces. These forces are summed forces due to the measuring position which is directly underneath the aCM. The current hypothesis is that they include dynamic friction forces during the insertion process and the forces needed to bend an initially straight EC into the curved form of the aCM. For the purposes of the present study, straight EC substitutes with a constant diameter of 0.7 mm and 20.5 mm intracochlear length were fabricated out of silicone in two versions with different stiffness by varying the number of embedded wires. The EC substitutes were inserted into three different models made of polytetrafluoroethylene (PTFE), each model showing only one constant radius. Three different insertion speeds were used (0.11 / 0.4 / 1.6 mm/s) with an automated insertion test bench. For each parameter combination (curvature, speed, stiffness) twelve insertions were conducted. Measurements included six full insertions and six paused insertions. Paused insertions include a ten second paused time interval without further insertion movement each five millimetres. Measurements showed that dynamic and static components of the measured summed forces can be identified. Dynamic force components increase with increased insertion speeds and also with increased stiffness of the EC substitutes. Both force components decrease with larger radius of the PTFE model. After the insertion, the EC substitutes showed a curved shape, which indicates a plastic deformation of the embedded wires due to the insertion into the curved models. The results can be used for further research on an analytical model to predict the insertions forces of a specific combination of selected parameters as insertion speed and type of EC, combined with given factors such as cochlear geometry

    Beyond hip fractures: other fragility fractures' associated mortality, functional and economic importance: a 2-year-Follow-up

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    BACKGROUND: Hip fractures are well researched in orthogeriatric literature. Equivalent investigations for fragility-associated periprosthetic and periosteosynthetic femoral, ankle joint, pelvic ring, and rib fractures are still rare. The purpose of this study was to evaluate mortality, functional outcome, and socioeconomic parameters associated to the upper-mentioned fragility fractures prospectively in a 2-year follow-up. METHODS: Over the course of a year, all periprosthetic and periosteosynthetic femoral fractures (PPFF), ankle joint fractures (AJ), pelvic ring fractures (PR), and rib fractures (RF), that were treated on a co-managed orthogeriatric ward, were assessed. Parker Mobility Score (PMS), Barthel Index (BI), place of residence, and care level were recorded. After 2 years, patients and/or relatives were contacted by mailed questionnaires or phone calls in order to calculate mortality and reevaluate the mentioned parameters. RESULTS: Follow-up rate was 77.7%, assessing 87 patients overall. The relative mortality risk was significantly increased for PR (2.9 (95% CI: 1.5–5.4)) and PPFF (3.5 (95% CI: 1.2–5.8)) but not for RF (1.5 (95% CI: 0.4–2.6)) and AJ (2.0 (95% CI: 0.0–4.0)). Every fracture group except AJ showed significantly higher BI on average at follow-up. PMS was, respectively, reduced on average for PR and RF insignificantly, but significantly for PPFF and AJ in comparison to pre-hospital values. 10.0–27.3% (each group) of patients had to leave their homes permanently; care levels were raised in 30.0–61.5% of cases. DISCUSSION: This investigation provides a perspective for further larger examinations. PR and PPFF correlate with significant increased mortality risk. Patients suffering from PPFF, PR, and RF were able to significantly recover in their activities of daily living. AJ and PPFF conclude in significant reduction of PMS after 2 years. CONCLUSION: Any fragility fracture has its impact on mortality, function, and socioeconomic aspects and shall not be underestimated. Despite some fractures not being the most common, they are still present in daily practice

    Prognostic impact of Claudin 18.2 in gastric and esophageal adenocarcinomas

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    Introduction: The tight junction molecule Claudin 18.2 is selectively expressed in healthy and malignant gastric epithelial tissue and is a promising therapy target for high Claudin 18.2 expressing adenocarcinomas of the esophagogastric junction and stomach (AEG/S). Methods: This study analyzed the prevalence, characteristics and prognostic impact of Claudin 18.2 expression in primary tumor, lymph node and distant metastasis in a large Caucasian AGE/S cohort with 414 patients. Results: Claudin 18.2 was highly expressed in 17.1% of primary tumors, 26.7% of lymph node metastasis and 16.7% of distant metastasis. High Claudin 18.2 expression in lymph node metastasis and primary tumors correlated significantly (p < 0.001). High expression of Claudin 18.2 was neither associated with histomorphogical subtype, or tumor state, nor with overall survival. Conclusion: In Caucasian AEG/S patients, 17.1% appeared to be eligible for an anti-Claudin 18.2 therapy. Claudin 18.2 expression itself has no impact on prognosis and is not related to any tumor subtype

    Brown bowel syndrome: A rare complication in diseases associated with long-standing malabsorption

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    BACKGROUND/AIMS Longtime chronic malabsorption may among other things cause a lack of liposoluble vitamins. Vitamin E deficiency can lead to formation of lipofuscin aggregates. Its deficiency is also associated with an increased lipofuscinosis of the bowel, i.e. brown bowel syndrome. METHODS Systematic research via Medline on brown bowel syndrome, lipofuscinosis, and vitamin E deficiency was performed. We combined our own clinical experience and a review of the literature for this paper. Its goal is to inform about the possible consequences of severe malabsorption and brown bowel syndrome. RESULTS Systematic data about the occurrence of severe malabsorption and brown bowel syndrome are rare. Only about 27 scientific reports can be found on this subject. Brown bowel syndrome is found mostly in conjunction with vitamin E deficiency and lipofuscinosis of the bowel. The clinical findings are caused by both malabsorption and lipofuscinosis. Case reports show a therapeutic effect of vitamin E. CONCLUSION Vitamin deficiency caused by longtime chronic malabsorption can lead to the development of brown bowel syndrome, which is seen as the expression of lipofuscinosis of the bowel, and can cause further clinical disorders. Patients with malabsorption should therefore be monitored regarding their vitamin E levels
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