Search

Potentially habitable icy Ocean Worlds, such as Enceladus and Europa, are scientifically compelling worlds in the solar system and high-priority exploration targets. Future robotic exploration of Enceladus and Europa by in-situ missions would require a detailed understanding of the surface material and of the complex lander-surface interactions during locomotion or sampling. To date, numerical modeling approaches that provide insights into the icy terrain's mechanical behavior have been lacking. In this work, we present a Discrete Element Model of porous planetary ice analogs that explicitly describes the microstructure and its evolution upon sintering. The model dimension is tuned following a Pareto-optimality analysis, the model parameters' influence on the sample strength is investigated using a sensitivity analysis, and the model parameters are calibrated to experiments using a probabilistic method. The results indicate that the friction coefficient and the cohesion energy density at the particle-scale govern the macroscopic properties of the porous ice. Our model reveals a good correspondence between the macroscopic and bond strength evolutions, suggesting that the strengthening of porous ice results from the development of a large-scale network due to inter-particle bonding. This work sheds light on the multi-scale nature of the mechanics of planetary ice analogs and points to the importance of understanding surface strength evolution upon sintering to design robust robotic systems. Graphic abstract, Granular Matter, 24 (1), ISSN:1434-5021, ISSN:1434-7636

Paraosteoarthropathien nach endoprothetischem Huftgelenksersatz und die sog. ”Myositis ossificans neurotica” nach traumatischen Hemi- und Paraplegien sind bekannte Phanomene. Eine vergleichsweise geringe Zahl von Publikationen berichtet uber exzessive Callusbildung nach Schadelhirntrauma.

Die limitierte Lebensdauer venoser Bypasse fuhrte zur Einfuhrung arteriellen Graftmaterials in die Herzchirurgie. Auch hier stellt sich dem Chirurgen jedoch das Problem der begrenzten Verfugbarkeit dieser autologen arteriellen Grafts. Die weitergehende intensive Suche nach alternativen Therapiekonzepten konzentrierte sich neben der Entwicklung von Allo- und Xenografts auch auf die ”naturliche” Angiogenese im menschlichen Organismus. Wachstumsfaktoren, wie der Heparin-bindende-Wachstumsfaktor HBGF-I, wirken uber ein hochaffines Rezeptorsystem, das auf der Zelloberflache lokalisiert ist und eine signifikante Steigerung der zellularen Proliferation, Migration und Differenzierung herbeifuhrt.

Dysphagia may occur in different diseases of the upper gastrointestinal tract. Even if a patient is not able to swallow, enteral nutrition is preferable to parenteral nutrition. Since nasogastric tubes cause severe psychological and nursing problems, we perform the percutaneous endoscopic gastrostomy (PEG) as an alternative method.

Kontroverse Diskussionen sind das „Salz im Eintopf medizinischer Kongresse". Darf die Sklerosierungstherapie der Osophagusvarizen nach jungsten Literaturmitteilungen (Binmoeller u. Soehendra 1991; Sauerbruch 1991; Soehendra et al. 1991) uberhaupt noch kontrovers diskutiert werden? Unsere eigenen Ergebnisse regen zumindest dazu an.

This paper reports on a patient who was treated by percutaneous aspiration, instillation of a sclerosant (polidocanol) and cystogastric drainage for a post-acute pancreatic pseudocyst. Five weeks after admission to hospital for the first episode of an acute necrotizing pancreatitis, the 60-year-old man underwent a percutaneous, ultrasound-guided puncture and aspiration of a voluminous pancreatic pseudocyst. Ten days later, recurrent fluid collection led to a second puncture, combined with the injection of polidocanol (15 ml; 1%) into the cyst cavity. Since this treatment failed, a percutaneous cystogastric drain ("double--pigtail") was inserted five days later. After developing acute abdominal pain and incipient sepsis, the patient was sent for surgical intervention twelve days after the second treatment with percutaneous aspiration and injection of polidocanol. During the operation an infected pancreatic pseudocyst with extensive contaminated necrosis of the pancreas and duodenal perforation was found. Necrectomy was performed, followed by continuous lavage of the omental bursa. Intensive care therapy was necessary for one week. Duodenal leakage persisted for nearly three weeks, the stopped spontaneously. The patient was discharged in quite a good state of health after 33 days of postoperative treatment. Although spontaneous development of infected pancreatic pseudocysts and pancreatic abscesses in necrotizing pancreatitis is known, a possible involvement of the drainage procedures, especially in combination with the injection of a sclerosant must be considered.

After anterolateral thoracotomy, before incision closure, indwelling plastic catheters were inserted percutaneously under digital and/or visual control into the intercostal space of access and the two neighbouring ones. Initially, we injected 25 mg of bupivacaine through each catheter (to a total of 75 mg), and subsequently - on the patients demand - another 15 to 25 mg per catheter. To date, 25 patients received repetitive intercostal nerve blocks by this method (ICB-group). We compared their personal and perioperative data with those of another 30 patients, receiving opiates systemically after major thoracic surgery (SA-group). Multiple blood samples from the ICB-group were analyzed by gaschromatography for bupivacaine concentration-time-profiles. In 19 of 25 patients (76%) the bupivacaine-injections provided sufficient analgesia, 6 patients required additional analgesics. The duration of general anaesthesia (ICB: 174 min vs. SA: 136 min) and the operation time (ICB: 103 min vs. SA: 94 min) were not statistically different in both groups. The periods of intensive care therapy (ICB: 0.7 d vs. SA: 1.2 d), artificial respiration (ICB: 11.2 h vs. SA: 21.6 h) and hospital stay (ICB: 12.1 d vs. SA: 14.2 d) were shorter for the ICB-group. Atelectasis (ICB: 20% vs. SA: 37%) and pneumonia (ICB: 0 vs. SA: 13%) were observed less frequently than in the control group, whereas tachyarrhythmia occurred in 6 of 25 ICB-patients compared to 4 of 30 SA-patients. Nevertheless, none of these parameters reached statistical significance (p less than 0.05). Maximum bupivacaine levels of 0.65 +/- 0.21 micrograms/ml were found after 29 +/- 12 min of intercostal application.(ABSTRACT TRUNCATED AT 250 WORDS)

Im Zeitraum von 1984 bis 1986 wurden 17 Patienten mit „schwerster“Peritonitis durch ein Nicht-Zunahen der Bauchhohle mit absichtlich programmierten, wiederholten Revisionen und massiven Spulungen behandelt. Das Nicht-Zunahen der Bauchhohle mit programmierter Peritoneallavage hielten wir fur angezeigt bei schwerster, diffuser uber 36 Stunden lang bestehender Perforations-Peritonitis, bei ausgedehnten Darmnekrosen vaskularer Genese mit Perforations- oder Penetrations-Peritonitis und bei pankreatischer Peritonitis. Von den 17 Patienten haben 10 uberlebt. Geheilt wurden diejenigen Patienten, bei denen sich das Organversagen nach der energischen Spulung und dem Offenlassen des massiven Infektherdes schnell zuruckbildete.