Tourenplanung kooperierender Spediteure unter Aspekten des dynamischen Teilladungsverkehrs

Both collaborative and dynamic vehicle routing represent intensively studied problems of discrete mathematics. However, scientific studies on the combination of these two fields are rare. Aspects of dynamic collaborative vehicle routing using the example of less than truckload transportation are examined in this dissertation. Independent actors use an auction mechanism to exchange transportation orders among each other. At the beginning of a planning horizon not all transportation orders are known. That is why a rolling horizon planning is used to overcome this uncertainty. In order to ensure long-term cooperationa s aspects of the cooperative game theory are respected. Therefore, allocation mechanisms are integrated into a rolling horizon planning for the first time. In computational experiments developed algorithms are tested and the practical impact is evaluated

In vitro Haemokompatibilitätstestung cardiovaskulärer Biomaterialien

Die Bedeckung cardiovaskulärer Bioprothesen mit autologen Endothel hat zum Ziel die Hämokompatibilität zu verbessern. Ziel dieser Arbeit ist es das Endothelialisierungspotential Glutaraldehyd-fixierter Herzklappenprothesen, sowie die zellulären Funktionen adhärenter Endothelzellen zu untersuchen. Weiterhin wurde der Einfluß einer zweizeitigen Besiedelung von humanen Fibroblasten und Endothelzellen auf deren fuktionelle Eigenschaften untersucht. Adhärenz und Morphologie der adhärierten Zellen wurde mittels Rasterelektronenmikroskopie und Immunhistochemie untersucht. Es konnte reproduzierbar eine vollständige Bedeckung von Glutaraldehyd-fixierten und detoxifizierten Herzklappenprothesen erreicht werden. Eine Analyse der direkt auf dem Material adhärenten Zellen ergab nicht-proliferative Zellen, die jedoch in der Lage waren auf inflammatorische Stimulation mit Interleukin-6 Sekretion, sowie mit Adhärenz inflammatorischer Zellen zu reagieren. Die Endothelzellen zeigten weiterhin erhaltene antithrombogene Eigenschaften, was mittels quantitativer Thrombozytenadhäsion und Sekretion von Prostacyclin gezeigt werden konnte. Eine Vorbesiedelung des Materials mit vaskulären Myofibroblasten gefolgt von Endothelzellen induzierte deren Proliferation und verbesserte inflammatorische sowie antithrombotische Eigenschaften. Cardiovaskuläre Biomaterialien unterscheiden sich deutlich bezüglich des Potentials die Adhärenz humaner Endothelzellen zu ermöglichen. Erfolgreich endothelialisierte Biomaterialien zeigen zelluläre Eigenschaften die die klinische Effektivität dieser Materialien verbessern könnten. Zweizeitige Besiedelung ermöglicht regeneratives Potential und verbessert die zellulären Eigenschaften der adhärenten Endothelzellen

Assessment of Association Between Venous Occlusion and Infection of Cardiac Implantable Electronic Devices

The increasing number of patients treated with cardiac implantable electronic devices (CIEDs) and indications for complex pacing requires system revisions. Currently, data on venous patency in repeat CIED surgery involving lead (re)placement or extraction are largely missing. This study aimed to assess venous patency and risk factors in patients referred for repeat CIED lead surgery, emphasizing CIED infection. All consecutive patients requiring extraction, exchange, or additional placement of ≥1 CIED leads during reoperative procedures from January 2015 to March 2020 were evaluated in this retrospective study. Venography was performed in 475 patients. Venous patency could be assessed in 387 patients (81.5%). CIED infection with venous occlusion was detected in 74 patients compared with venous occlusion without infection in 14 patients (P < .05). Concerning venous patency, novel oral anticoagulant medication appeared to be protective (P < .05; odds ratio [OR]: .35). Infection of the CIED appeared to be strongly associated with venous occlusion (OR: 16.0). The sensitivity was only 64.15%, but the specificity was 96.1%. Number of leads involved and previous CIED procedures were not associated with venous occlusion. In conclusion, in patients with CIED, venous occlusion was strongly associated with device infection, but not with the number of leads or previous CIED procedures

Multi‐organ dysfunction syndrome in patients undergoing extracorporeal life support

Background Multiple organ failure is a common complication in patients undergoing ECLS significantly affecting patient outcomes. Gaining knowledge about the mechanisms of onset, clinical course, risk factors, and potential therapeutic targets is highly desirable. Methods Data of 354 patients undergoing ECLS with one-, two, three-, and four organ failures were retrospectively analyzed. Incidence of multiple organ dysfunction (MODS), its impact on survival, risk factors for its occurrence, and the impact of proinflammatory mediators on the occurrence of MODS in patients undergoing ECLS were investigated. Results The median follow-up was 66 (IQR 6; 820) days. 245 (69.2%) patients could be weaned from ECLS, 30-day survival and 1-year survival were 194 (54.1%) and 157 (44.4%), respectively. The duration of mechanical support was 4 (IQR 2; 7) days in the median. Increasing severity of MODS resulted in significant prolongation of mechanical circulatory support and worsening of the outcome. Liver dysfunction had the strongest impact on patient mortality (OR = 2.5) and survival time (19 vs 367 days). The serum concentration of analyzed interleukins rose significantly with each, additional organ affected by dysfunction (p < 0.001). All analyzed proinflammatory cytokines showed significant predictivity relative to the occurrence of MODS with interleukin 8 serum level prior to ECLS showing the strongest predictive potential for the occurrence of MODS (AUC 0.78). Conclusion MODS represents a frequent complication in patients undergoing ECLS with a significant impact on survival. Proinflammatory cytokines show prognostic capacity regarding the occurrence and severity of multi-organ dysfunction

Ablation of atrial fibrillation with the Epicor system: a prospective observational trial to evaluate safety and efficacy and predictors of success

<p>Abstract</p> <p>Background</p> <p>High intensity focused ultrasound (HIFU) energy has evolved as a new surgical tool to treat atrial fibrillation (AF). We evaluated safety and efficacy of AF ablation with HIFU and analyzed predictors of success in a prospective clinical study.</p> <p>Methods</p> <p>From January 2007 to June 2008, 110 patients with AF and concomitant open heart surgery were enrolled into the study. Main underlying heart diseases were aortic valve disease (50%), ischemic heart disease (48%), and mitral valve disease (18%). AF was paroxysmal in 29%, persistent in 31%, and long standing persistent in 40% of patients, lasting for 1 to 240 months (mean 24 months). Mean left atrial diameter was 50 ± 7 mm. Each patient underwent left atrial ablation with the Epicor system prior to open heart surgery. After surgery, the patients were treated with amiodarone and coumadin for 6 months. Follow-up studies including resting ECG, 24 h Holter ECG, and echocardiography were obtained at 6 and 12 months.</p> <p>Results</p> <p>All patients had successful application of the system on the beating heart prior to initiation of extracorporeal circulation. On average, 11 ± 1 ultrasound transducer elements were used to create the box lesion. The hand-held probe for additional linear lesions was employed in 83 cases. No device-related deaths occurred. Postoperative pacemaker insertion was necessary in 4 patients. At 6 months, 62% of patients presented with sinus rhythm. No significant changes were noted at 12 months. Type of AF and a left atrial diameter > 50 mm were predictors for failure of AF ablation.</p> <p>Conclusion</p> <p>AF ablation with the Epicor system as a concomitant procedure during open heart surgery is safe and acceptably effective. Our overall conversion rate was lower than in previously published reports, which may be related to the lower proportion of isolated mitral valve disease in our study population. Left atrial size may be useful to determine patients who are most likely to benefit from the procedure.</p

A novel small-caliber bacterial cellulose vascular prosthesis: production, characterization, and preliminary in vivo testing

Vascular grafts are used to bypass damaged or diseased blood vessels. Bacterial cellulose (BC) has been studied for use as an off-the-shelf graft. Herein, we present a novel, cost-effective, method for the production of small caliber BC grafts with minimal processing or requirements. The morphology of the graft wall produced a tensile strength above that of native vessels, performing similarly to the current commercial alternatives. As a result of the production method, the luminal surface of the graft presents similar topography to that of native vessels. We have also studied the in vivo behavior of these BC graft in order to further demonstrate their viability. In these preliminary studies, 1 month patency was achieved, with the presence of neo-vessels and endothelial cells on the luminal surface of the graft.This study was supported by the Portuguese Foundation for Science and Technology (FCT) and the European Community fund FEDER, through Program COMPETE, under the scope of the Projects FCOMP-01-0124-FEDER-007025 (PTDC/AMB/68393/2006), PEST-OE/EQB/LA0023/2013, PEST-C/FIS/UI607/2013, RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Projects "BioEnv-Biotechnology and Bioengineering for a sustainable world" and "Matepro-Optimizing Materials and Processes". NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER. The authors also acknowledge the fellowship awarded to Alexandre Felipe Leitao (SFRH/BD/66094/2009) funded by the Fundacao para a Ciencia e Tecnologia (FCT). The authors also thank support by FCT through the project BCGrafts, FCOMP-01-0124-FEDER-014773 (PTDC/EBB/EBI/112170/2009) and by the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program FP7/2007-2013/under REA grant agreement n317512