Total Cost of Services (TCS) von Learning Management-Systemen

Mit dem zunehmenden Einsatz von E-Learning-Plattformen rücken verstärkt Wirtschaftlichkeitsaspekte in den Betrachtungsmittelpunkt, die Methoden zur Ermittlung systembedingter Kosten voraussetzen. Durch die zunehmende Serviceorientierung und Integration von LMS mit bestehenden Komponenten der Anwendungsarchitektur sind hierfür jedoch neue Methoden notwendig, welche die Defizite traditioneller Total Cost of Ownership-Modelle abbauen. Einen Ansatzpunkt hierfür bietet das ITIL-Referenzmodell, das einen Rahmen für taktische und operative IT-Services vorgibt und somit die Grundlage für eine serviceorientierte Gesamtkostenermittlung in Form der Total Cost of Services (TCS) liefert.

3D-Druck von Kunststoff-Medizinprodukten

Das Additive Manufacturing gewinnt im Bereich der Medizintechnik zur Herstellung von Prototypen bis hin zu Endprodukten zunehmend an Bedeutung. Ein großes Hemmnis stellen allerdings die relativ hohen Fertigungskosten dar. Hier bietet der verstärkte Einsatz der 3D-Drucktechnologie (3D Printing) ein erhebliches Potential zur Reduktion der Kosten. Aus dieser Motivation heraus wurde ein 3D-Druckverfahren zur Herstellung biokompatibler, sterilisierbarer Kunststoffmodelle entwickelt. Beim 3D-Druck-Verfahren handelt es sich um einen pulverbasierten Prozess zur schichtweisen Herstellung von Modellen direkt aus Computerdaten. Dabei werden dünne Schichten eines Pulvers auf eine Grundplatte aufgebracht, die dann durch gezielte Binderzugabe entsprechend des aktuellen Bauteilquerschnitts verfestigt werden. Ausgangsmaterial für diesen Prozess ist ein Granulatgemisch auf Basis von PMMA (Polymethylmethacrylat). Als Binderflüssigkeit wird ein Lösungsmittel eingesetzt. Die 3D gedruckten Modelle werden nach einer entsprechenden Trocknungszeit im Pulverbett entpackt und warmgelagert, um das Abdampfen des Lösungsmittels zu beschleunigen. Der Nachweis der Biokompatibilität der hergestellten Modelle erfolgte durch einen Test nach DIN EN ISO 10993-5. In Kooperation mit Anwendern wurden verschiedene Anwendungsbeispiele wie Bohrschablonen, Otoplastiken, Gebissmodelle und Modelle für die präoperative Planung realisiert und charakterisiert.

The von Mises-Fisher distribution of the first exit point from the hypersphere of the drifted Brownian motion and the density of the first exit time

A characterization is provided for the von Mises–Fisher random variable, in terms of first exit point from the unit hypersphere of the drifted Wiener process. Laplace transform formulae for the first exit time from the unit hypersphere of the drifted Wiener process are provided. Post representations in terms of Bell polynomials are provided for the densities of the first exit times from the circle and from the sphere.

3D scaffolds co-seeded with human endothelial progenitor and mesenchymal stem cells: evidence of prevascularisation within 7 days

Blood supply is a critical issue in most tissue engineering approaches for large defect healing. As vessel ingrowth from surrounding tissues is proven to be insufficient, current strategies are focusing on the neo-vascularisation process. In the present study, we developed an in vitro pre-vascularised construct using 3D polyurethane (PU) scaffolds, based on the association of human Endothelial Progenitor Cells (EPC, CD34+ and CD133+) with human Mesenchymal Stem Cells (MSC). We showed the formation of luminal tubular structures in the co-seeded scaffolds as early as day 7 in culture. These tubular structures were proven positive for endothelial markers von Willebrand Factor and PECAM-1. Of special significance in our constructs is the presence of CD146-positive cells, as a part of the neovasculature scaffolding. These cells, coming from the mesenchymal stem cells population (MSC or EPC-depleted MSC), also expressed other markers of pericyte cells (NG2 and αSMA) that are known to play a pivotal function in the stabilisation of newly formed pre-vascular networks. In parallel, in co-cultures, osteogenic differentiation of MSCs occurred earlier when compared to MSCs monocultures, suggesting the close cooperation between the two cell populations. The presence of angiogenic factors (from autologous platelet lysates) in association with osteogenic factors seems to be crucial for both cell populations' cooperation. These results are promising for future clinical applications, as all components (cells, growth factors) can be prepared in an autologous way.

"Fascinating Voids: Alexander von Humboldt and the Myth of Chimborazo"

When Alexander von Humboldt reached the village of Calpi in the Andes on 22 June 1802, he was greeted with reverence and enthusiasm. Triumphal arches adorned with cotton, cloth, and silver decorated his path. The natives performed a dance in festive dress. A singer praised the explorer's expedition, which had departed three years earlier from the Spanish port of La Coruña. Like Odysseus on the isle of the Phaeacians, the traveler listened to a local rhapsodist singing about his heroic deeds. Before his adventure ended, it had already spun a popular myth. This episode, which Humboldt recorded in his diary, occurred at a significant moment. One day later, the “Second Discoverer of America” rose to even greater fame on an excursion marking in more ways than one the climax of his enterprise. Humboldt set out to climb Chimborazo (6,310 m/20,702 ft.), the mountain then thought to be the highest in the world. He was accompanied by the French botanist Aimé Bonpland (1773–1858) and the Creole nobleman and future activist Carlos Montúfar (1780–1816), as well as native guides and assistants. They climbed to heights never reached before, setting a new record and catapulting Humboldt to fame on both continents.

Konstruktion und erste Validierung eines Fragebogens zur umfassenden Erfassung von Achtsamkeit: Das Comprehensive Inventory of Mindfulness Experiences

In der vorliegenden Arbeit werden Entwicklung und Validierung eines Fragebogens zur umfassenden Erfassung der Achtsamkeit, des Comprehensive Inventory of Mindfulness Experiences (CHIME), beschrieben. An einer Allgemeinbevölkerungs-Stichprobe (N = 298) und einer Stichprobe von TeilnehmerInnen an MBSR-Kursen (N = 161) wurde die Faktorenstruktur des CHIME ermittelt und seine Reliabilität und Validität geprüft. Faktorenanalytische Verfahren ergaben eine achtfaktorielle Struktur. Die Struktur wurde in einer zusätzlichen konfirmatorischen Stichprobe (N = 202) überprüft. Der Fragebogen sowie seine Unterskalen weisen gute Reliabilitätswerte auf (interne Konsistenz und Retest-Reliabilität). Analysen zur Messinvarianz der einzelnen Items über Gruppen, die sich bezüglich Meditationserfahrung, Alter, Geschlecht und Symptombelastung unterschieden, zeigten keine systematischen Unterschiede im Verständnis der Items. Die Kennwerte zur Konstrukt-, Kriterium-, und inkrementellen Validität sowie zur Veränderungssensitivität waren alle mindestens zufriedenstellend. Mit dem CHIME steht somit ein Fragebogen mit guten psychometrischen Eigenschaften zur Selbsteinschätzung der Achtsamkeit zur Verfügung. Der CHIME basiert auf allen in den aktuellen Instrumenten enthaltenen Aspekten des Achtsamkeitskonstrukts.

Evidence for the involvement of proximal chromosome 3P loci in the progression of Von Hippel-Lindau related tumors

Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder characterized by the development of retinal and central nervous system hemangioblastoma, renal cell carcinoma (RCC), pheochromocytoma and pancreatic islet cell tumors (PICT). The VHL gene maps to chromosome 3p25 and has been shown to be mutated in 57% of sporadic cases of RCC, implicating VHL in the genesis of RCC. We report a multigeneration VHL kindred in which four affected female siblings developed PICT at early ages. Analysis of the three coding exons of the VHL gene in this family revealed a single, missense mutation in codon 238. Inheritance of the 238 mutation has been reported to correlate with a 62% risk of pheochromocytoma development. In this kindred, all affected individuals carried the mutation as well as one additional sibling who showed no evidence of disease. Clinical screening of this individual indicated small ($<$1 cm) pancreatic and kidney tumors. Results suggest that inheritance of the codon 238 mutation does not correlate with early onset pheochromocytoma. Rather, the only individual in the pedigree with pheochromocytoma was the proband's mother who developed bilateral pheochromocytoma at the age of 62. Thus, the VHL codon 238 mutation may predispose to late onset pheochromocytoma in this family; however, it does not explain the preponderance of PICT in the third generation since this mutation has not been reported to increase the risk of developing pancreatic lesions. This suggests that inheritance of the codon 238 mutation and subsequent somatic inactivation of the wild type allele of the VHL gene may not be sufficient to explain the initiation and subsequent progression to malignancy in VHL-associated neoplasms. Since the two tumor types that most frequently progress to malignancy are RCC and PICT, we asked whether loss of heterozygosity (LOH) could be detected proximal to the VHL gene on chromosome 3 in distinct regions of 3p previously implicated by LOH and cytogenetic studies to contain tumor suppressor loci for RCC. LOH was performed on high molecular weight DNA isolated from peripheral blood and frozen tumor tissue of family members using microsatellite markers spanning 3p. Results indicated LOH for all informative 3p loci in tumor tissue from affected individuals with PICT. LOH was detected along the entire length of the chromosome arm and included the proximal region of 3p13-14.2 implicated in the hereditary form of renal cell carcinoma.^ If 3p LOH were a critical event in pancreatic islet cell tumorigenesis, then it should be expected that LOH in sporadic islet cell tumors would also be observed. We expanded LOH studies to include sporadic cases of PICT. Consistent LOH was observed on 3p with a highest frequency LOH in the region 3p21.2. This is the first evidence for an association between chromosome 3 loci and pancreatic islet cell tumorigenesis. (Abstract shortened by UMI.) ^

The scholarly networks of Albrecht von Haller and the Economic Society of Bern – a multi-level network analysis

Here, by the example of the transfer of cultivated plants in the context of the correspondence networks of Albrecht von Haller and the Economic Society, a multi-level network analysis is suggested. By a multi-level procedure, the chronological dynamics, the social structure, the spatial distribution and the functional networking are analyzed one after the other. These four levels of network analysis do not compete with each other but are mutually supporting. This aims at a deeper understanding of how these networks contributed to an international transfer of knowledge in the 18th century.