1,015 research outputs found

    On state-alternating context-free grammars

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    AbstractState-alternating context-free grammars are introduced, and the language classes obtained from them are compared to the classes of the Chomsky hierarchy as well as to some well-known complexity classes. In particular, state-alternating context-free grammars are compared to alternating context-free grammars (Theoret. Comput. Sci. 67 (1989) 75–85) and to alternating pushdown automata. Further, various derivation strategies are considered, and their influence on the expressive power of (state-) alternating context-free grammars is investigated

    Komplement-induzierte Kalziumsignale am retinalen Pigmentepithel vor dem Hintergrund der altersbedingten Makuladegeneration

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    Introduction: The retinal pigment epithelium (RPE) plays an important role as an interaction partner for numerous cell functions within the immune system. Complement components can induce Ca2+- signals at the RPE whereby a dysregulated complement system is associated with an increased risk of AMD genesis. Methods: Recording of Ca2+-signals and analysis of signalling pathways using Ca2+-imaging on ARPE-19 cells; statistical analysis using Microsoft Excel and GraphPad Prism 8. Results: Different components of the complement system (including C3a, C5a, terminal complex) generate an individual and finely orchestrated Ca2+-signal without any sign of a lytic pore. Conclusion: Specific signals induced by complement can trigger a change in the functional phenotype of the RPE. It can be assumed that the RPE can adapt so precisely to its environment and thus significantly influence the AMD pathogenesis.Einleitung: Das retinale Pigmentepithel (RPE) spielt als Interaktionspartner eine bedeutende Rolle für zahlreiche Zellfunktionen innerhalb des Immunsystems. Komplement kann am RPE Ca2+-Signale induzieren, wobei ein fehlreguliertes Komplementsystem mit einem erhöhten AMD-Risiko einhergeht. Methodik: Aufzeichnung von Ca2+-Signalen und Analyse von Signalwegen mittels Ca2+- Imaging an ARPE-19-Zellen; statistische Auswertung mithilfe von Microsoft Excel und GraphPad Prism 8. Ergebnisse: Unterschiedliche Komponenten des Komplementsystems (u.a. C3a, C5a, terminaler Komplex) erzeugen ein individuelles und fein orchestriertes Ca2+-Signal, Anzeichen einer lytischen Pore fehlen. Schlussfolgerung: Spezifische, durch Komplement induzierte Signale können am RPE eine Veränderung des funktionellen Phänotyps auslösen. Es ist anzunehmen, dass das RPE sich so präzise seiner Umgebung anpassen und die AMD-Pathogenese damit maßgeblich beeinflussen kann

    A Subtle Interplay Between Three Pex11 Proteins Shapes De Novo Formation and Fission of Peroxisomes

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    The organization of eukaryotic cells into membrane-bound compartments must be faithfully sustained for survival of the cell. A subtle equilibrium exists between the degradation and the proliferation of organelles. Commonly, proliferation is initiated by a membrane remodeling process. Here, we dissect the function of proteins driving organelle proliferation in the particular case of peroxisomes. These organelles are formed either through a growth and division process from existing peroxisomes or de novo from the endoplasmic reticulum (ER). Among the proteins involved in the biogenesis of peroxisomes, peroxins, members of the Pex11 protein family participate in peroxisomal membrane alterations. In the yeast Saccharomyces cerevisiae, the Pex11 family consists of three proteins, Pex11p, Pex25p and Pex27p. Here we demonstrate that yeast mutants lacking peroxisomes require the presence of Pex25p to regenerate this organelle de novo. We also provide evidence showing that Pex27p inhibits peroxisomal function and illustrate that Pex25p initiates elongation of the peroxisomal membrane. Our data establish that although structurally conserved each of the three Pex11 protein family members plays a distinct role. While ScPex11p promotes the proliferation of peroxisomes already present in the cell, ScPex25p initiates remodeling at the peroxisomal membrane and ScPex27p acts to counter this activity. In addition, we reveal that ScPex25p acts in concert with Pex3p in the initiation of de novo peroxisome biogenesis from the ER

    Benefits of cardiac surgery in octogenarians — a postoperative quality of life assessment

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    Objective: Assessment of postoperative quality of life in patients over 80 years after cardiac surgery including coronary artery bypass grafting (CABG), aortic valve replacement (AVR) and combined procedures. Methods: Quality of life of n=136 patients over 80 years at operation (82.3±2.1 years), undergoing isolated CABG in 61 patients (45%), isolated AVR in 34 patients (25%) and a combination of CABG and AVR in 41 patients (30%) between January 1999 and December 2003 was reviewed. Preoperatively 66.2% presented in NYHA-class III/IV or CCS-class III/IV. Mean ejection fraction (EF) was 59.5%±14.0 (range 25-90%). Quality of life assessment was performed via a Seattle Angina Questionnaire. Follow-up was 100% complete for a total of 890 days (69-1853 days). Results: Five-year survival was 70% for the CABG group, 75% for the AVR group and 65% for the CABG/AVR group. Quality of life was remarkable in all of the three groups after surgery. Overall 97 patients (81%) were not or little disabled in their daily activity. One hundred and twelve patients (93%) were free or considerably less symptomatic. Seventy-eight patients or 65% reported to be very satisfied with their current quality of life and 112 patients (93%) felt very reassured to have continuous full access to medical treatment despite of their advanced age. Conclusions: A remarkable quality of life and important improvement in the functional status after cardiac surgery in patients over 80 paired with a satisfactory medium-term survival justify early intervention for heart disease in this age group. Therefore, referral practice for patients over 80 years for heart surgery should be handled liberall

    Draft Genome Sequence of the Acidophilic, Halotolerant, and Iron/Sulfur-Oxidizing Acidihalobacter prosperus DSM 14174 (Strain V6).

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    The principal genomic features of Acidihalobacter prosperus DSM 14174 (strain V6) are presented here. This is a mesophilic, halotolerant, and iron/sulfur-oxidizing acidophile that was isolated from seawater at Vulcano, Italy. It has potential for use in biomining applications in regions where high salinity exists in the source water and ores

    Systemic Capillary Leak Syndrome associated with hypovolemic shock and compartment syndrome. Use of transpulmonary thermodilution technique for volume management

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    Systemic Capillary Leak Syndrome (SCLS) is a rare disorder characterized by increased capillary hyperpermeability leading to hypovolemic shock due to a markedly increased shift of fluid and protein from the intravascular to the interstitial space. Hemoconcentration, hypoalbuminemia and a monoclonal gammopathy are characteristic laboratory findings. Here we present a patient who suffered from SCLS with hypovolemic shock and compartment syndrome of both lower legs and thighs. Volume and catecholamine management was guided using transpulmonary thermodilution. Extended hemodynamic monitoring for volume and catecholamine management as well as monitoring of muscle compartment pressure is of crucial importance in SCLS patients

    A digital calorimetric trigger for the COMPASS experiment at CERN

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    In order to provide a trigger for the Primakoff reaction, in 2009, the trigger system of the COMPASS experiment at CERN will be extend by an electromagnetic calorimeter trigger. Since it was decided to gain from various benefits of digital data processing, an FPGA based implementation of the trigger is foreseen, running on the front-end electronics, which are used for data acquisition at the same time. This, however, includes further modification of the existing trigger system to combine the digital calorimeter trigger, with its higher latency, and the analogue trigger signals, which will also make use of digital data processing

    Humanoids for teaching and training coronary artery bypass surgery to the next generation of cardiac surgeons

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    Objectives: Technical skills are an essential component of cardiac surgery, and the operating room is becoming an even more challenging environment for trainees who want to acquire such skills. Simulation, which partially overcomes this limitation, represents a valid adjunct to surgical education. We describe an original simulator and provide results in terms of trainees' evaluations and ratings. Methods: We used a humanoid that is a silicone replica of the chest of an adult human that provides a complete anatomical platform for hands-on skin-to-skin practice of surgical techniques in arrested heart coronary artery bypass graft (CABG) surgery cases. Learners were residents in cardiac surgery. The teaching sessions included 2 full three-vessel CABG procedures using both mammary arteries and a hydrogel vein. Five board-certified cardiovascular surgeons scored the surgical activity of all trainees. The trainees were asked to complete an exit questionnaire to evaluate their course. Results: Overall, 16 residents participated in the simulation, including 5 women and 11 men, with a mean age of 30 ± 4 years, all of whom had at least 2 years of cardiac surgery training. All participants completed the 2 CABG operations. Three mammary arteries (4.6%) were seriously damaged during harvesting. In 1 case (3.1%), an aortic tear occurred during aortic cannulation. Each trainee performed overall 6 distal and 2 proximal coronary anastomoses. All participants agreed that the 'humanoid reproduces real-life situations, the feeling is realistic, and they are now more confident in performing coronary anastomosis'. Conclusions: Trainees involved in this simulation curriculum acquired and refined technical skills that could be applied directly to human patients. In addition, we were able to foster a higher level of teamwork within the operating room team. Keywords: Coronary artery bypass grafting; Surgical simulator; Trainin

    Geriatrische Assessments und Diagnostik beim älteren Patienten

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    As is the case with younger patients, the treatment decisions for elderly patients with thoracic tumours are primarily based on the results of the usual routine diagnostics. Standardised assessments of existing comorbidities and geriatric assessments may provide information which are of particular relevance for intensive and/or complex therapy modalities and which may require early corresponding intervention or measures for support
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