Four phases of video streaming: A case study of medical teaching

This article examines video streaming in teaching situations with varying degrees of student activation ranging from lectures to team-based learning. The article is a case study of the implementation of video streaming at the Department of Medicine, Aarhus University. The aim of the article is to develop a model of video streaming in student-centered teaching. The research question is what characterizes the phases of video streaming in relation to student-centered teaching? The article develops a model with four phases of video streaming based on the case study and the literature on learning design. The article argues that both educators, e-moderators and students play a role in making video streaming a useful teaching technology. There are advantages to embedding the technology in a social educational context in relation to roles and phases of teaching. In collaboration with educators, instructional developers must learn to see the possibilities of video streaming from the perspective of the instructional process.Denne artikel undersøger videostreaming i forskellige undervisningssituationer med varierende grader af studenteraktivering lige fra forelæsninger til team-baseret læring. Artiklen er et casestudie om implementering af video-streaming på Medicin, Aarhus Universitet. Artiklens mål er at udvikle en model af videostreaming i studenter-centreret undervisning. Forskningsspørgsmålet er: Hvad kendetegner faser i video-streaming i forhold til studentercentreret undervisning? Artiklen udvikler en model med fire faser af videostreaming baseret på et empirisk casestudie og teori om læringsdesign. Artiklen argumenterer for at både undervisere, e-moderatorer og studerende spiller en rolle i forhold til at gøre video-streaming til en nyttig undervisningsteknologi. Selvom universitetsundervisere relativt nemt kan udvikle videoer med sin smartphone eller ved hjælp af et digitalt videokamera, er der fordele ved at indlejre teknologien i en social uddannelsessammenhæng i forhold til roller og faser i undervisningsforløb. Undervisningsudviklere skal i samarbejde med undervisere lære at se mulighederne i video-streaming ud fra et undervisningsforløb

Blood-Brain Barrier Transport of Transferrin Receptor-Targeted Nanoparticles

The blood–brain barrier (BBB), built by brain endothelial cells (BECs), is impermeable to biologics. Liposomes and other nanoparticles are good candidates for the delivery of biologics across the BECs, as they can encapsulate numerous molecules of interest in an omnipotent manner. The liposomes need attachment of a targeting molecule, as BECs unfortunately are virtually incapable of uptake of non-targeted liposomes from the circulation. Experiments of independent research groups have qualified antibodies targeting the transferrin receptor as superior for targeted delivery of nanoparticles to BECs. Functionalization of nanoparticles via conjugation with anti-transferrin receptor antibodies leads to nanoparticle uptake by endothelial cells of both brain capillaries and post-capillary venules. Reducing the density of transferrin receptor-targeted antibodies conjugated to liposomes limits uptake in BECs. Opposing the transport of nanoparticles conjugated to high-affine anti-transferrin receptor antibodies, lowering the affinity of the targeting antibodies or implementing monovalent antibodies increase uptake by BECs and allows for further transport across the BBB. The novel demonstration of transport of targeted liposomes in post-capillary venules from blood to the brain is interesting and clearly warrants further mechanistic pursuit. The recent evidence for passing targeted nanoparticles through the BBB shows great promise for future drug delivery of biologics to the brain

Post-capillary venules are the key locus for transcytosis-mediated brain delivery of therapeutic nanoparticles

Effective treatments of neurodegenerative diseases require drugs to be actively transported across the blood-brain barrier (BBB). However, nanoparticle drug carriers explored for this purpose show negligible brain uptake, and the lack of basic understanding of nanoparticle-BBB interactions underlies many translational failures. Here, using two-photon microscopy in mice, we characterize the receptor-mediated transcytosis of nanoparticles at all steps of delivery to the brain in vivo. We show that transferrin receptor-targeted liposome nanoparticles are sequestered by the endothelium at capillaries and venules, but not at arterioles. The nanoparticles move unobstructed within endothelium, but transcytosis-mediated brain entry occurs mainly at post-capillary venules, and is negligible in capillaries. The vascular location of nanoparticle brain entry corresponds to the presence of perivascular space, which facilitates nanoparticle movement after transcytosis. Thus, post-capillary venules are the point-of-least resistance at the BBB, and compared to capillaries, provide a more feasible route for nanoparticle drug carriers into the brain

Dynamic breaking of a single gold bond

AbstractWhile one might assume that the force to break a chemical bond gives a measure of the bond strength, this intuition is misleading. If the force is loaded slowly, thermal fluctuations may break the bond before it is maximally stretched, and the breaking force will be less than the bond can sustain. Conversely, if the force is loaded rapidly it is more likely that the maximum breaking force is measured. Paradoxically, no clear differences in breaking force were observed in experiments on gold nanowires, despite being conducted under very different conditions. Here we explore the breaking behaviour of a single Au–Au bond and show that the breaking force is dependent on the loading rate. We probe the temperature and structural dependencies of breaking and suggest that the paradox can be explained by fast breaking of atomic wires and slow breaking of point contacts giving very similar breaking forces.</jats:p

Scripts to pull gold wires and plot results

Scripts used to pull thin gold nanowires apart at varying stretching rates. <div>Records forces on the terminal atoms, does a linear fit on the forces to find the breaking force. </div><div><br></div><div>`new_thinwire_aggregation` collects the breaking forces for individual pulls and makes a plot over several stretching rates. </div

Change in breaking pattern for a gold junction

Simulation of the repeated breaking of a gold nanowire. It was pulled apart and pushed back together until the minimal cross-section corresponded to a conductance of 9G0. <div><br></div><div>The movie shows 2 cycles of the same breaking behaviour, then a change in behaviour, and then 2 cycles of the new behaviour. </div

3 gold junctions, varying crystal plane

xyz files of 3 different initial gold structures. They differ mainly in the direction of the junction compared to the crystal planes (100), (110), (111

Computational Methods for Automated Generation of Enzyme Mutants

<p>Bachelor thesis from the Department of Chemistry, University of Copenhagen, Denmark</p