Centrifuge modelling of monopiles in dense sand at The Technical University of Denmark

The pile-soil interaction is of great importance in the design of monopiles supporting offshore wind turbines. Especially the predication of accumulation of rotations, change in stiffness and damping is difficult. The design tools used today cannot in a proper way take the effects from cyclic, lateral loading into account. In order to develop simple design tools for cyclic lateral loading, a large centrifuge test series is ongoing at the Technical University of Denmark (DTU). This paper presents the main conclusions found from centrifuge testing over the last 4 years and gives indication where research is going. From monotonic tests \u93modelling of models\u94 has been performed to identify scaling errors. It appears that the non-linear stress distributions occurring in centrifuge tests should be taken into account when dealing with stiff monopiles. Also the effect from load eccentricity has been investigated and initial results indicate that the normalised initial stiffness is unaffected but the ultimate capacity is increased by increasing load eccentricity. Accumulation of rotations and increase in secant stiffness has been seen from cyclic, load-controlled tests. One initial test has been used to generate cyclic p-y curves and is here presented. This is the first step in the development of a cyclic spring element which can be used as a simple engineering tool in the prediction of accumulation of rotations, change in stiffness and damping

Hvordan kan teknologi påvirke pædagogiske og didaktiske praksisser?

Denne artikel introducerer en bestemt forståelse af uddannelsespraksisser som socio/tekniske begivenheder. Formålet er at fremkomme med et bud på teknologiens betydning for pædagogiske og didaktiske praksisser uden at forfalde til teknologisk determinisme (Heilbroner, 1967) eller blot at konstatere teknologiens effekter som en ‘kulturkraft’ (Hasse & Storgaard, 2015). I artiklens første del præsenteres en analyse af en skoles økologi som en heterogen socio/teknisk konstellation der muliggør bestemte begivenheder. Analysen baserer sig på en teori om bindingers (eng. constraints) (Bjørn & Østerlund, 2014; Fraser, 1989; Shogan, 1999) betydning for iværksættelsen af begivenheder, hvor teknologi forstås som social først og teknisk sekundært (Deleuze, 1999). Ud fra denne forståelsesramme bliver det muligt, i artiklens anden del, at analysere empiri fra den igangværende introduktion af læringsplatforme i danske folkeskolers økologier. Vi konkluderer at teknologier såsom læringsplatforme på sigt vil revolutionere uddannelse, men at brugerportalsinitiativet i dets nuværende form ikke ændrer afgørende på bindinger på didaktisk og pædagogisk praksis

The low binding affinity of D-serine at the ionotropic glutamate receptor GluD2 can be attributed to the hinge region

Ionotropic glutamate receptors (iGluRs) are responsible for most of the fast excitatory communication between neurons in our brain. The GluD2 receptor is a puzzling member of the iGluR family: It is involved in synaptic plasticity, plays a role in human diseases, e.g. ataxia, binds glycine and D-serine with low affinity, yet no ligand has been discovered so far that can activate its ion channel. In this study, we show that the hinge region connecting the two subdomains of the GluD2 ligand-binding domain is responsible for the low affinity of D-serine, by analysing GluD2 mutants with electrophysiology, isothermal titration calorimetry and molecular dynamics calculations. The hinge region is highly variable among iGluRs and fine-tunes gating activity, suggesting that in GluD2 this region has evolved to only respond to micromolar concentrations of D-serine

Modest de novo Reactivation of Single HIV-1 Proviruses in Peripheral CD4+ T Cells by Romidepsin

A cure for human immunodeficiency virus (HIV-1) is restricted by the continued presence of a latent reservoir of memory CD4+ T cells with proviruses integrated into their DNA despite suppressive antiretroviral therapy (ART). A predominant strategy currently pursued in HIV-1 cure-related research is the “kick and kill” approach, where latency reversal agents (LRAs) are used to reactivate transcription from integrated proviruses. The premise of this approach is that “kicking” latent virus out of hiding allows the host immune system to recognize and kill infected cells. Clinical trials investigating the efficacy of LRAs, such as romidepsin, have shown that these interventions do induce transient spikes in viral RNA in HIV-1-infected individuals. However, since these trials failed to significantly reduce viral reservoir size or significantly delay time to viral rebound during analytical treatment interruptions, it is questioned how much each individual latent provirus is actually “kicked” to produce viral transcripts and/or proteins by the LRA. Here, we developed sensitive and specific digital droplet PCR-based assays with single-provirus level resolution. Combining these assays allowed us to interrogate the level of viral RNA transcripts from single proviruses in individuals on suppressive ART with or without concomitant romidepsin treatment. Small numbers of proviruses in peripheral blood memory CD4+ T cells were triggered to become marginally transcriptionally active upon romidepsin treatment. These novel assays can be applied retrospectively and prospectively in HIV-1 cure-related clinical trials to gain crucial insights into LRA efficacy at the single provirus level