Kleine deeltjes, grote kwesties: Een issueanalyse van de maatschappelijke dialoog nanotechnologie

Dit artikel beantwoordt de vraag welke kwesties aan bod zijn gekomen in de Maatschappelijke Dialoog Nanotechnologie en in hoeverre deze dialoog heeft bijgedragen aan verbreding van het debat. Is het gelukt naast een technologisch ook een maatschappelijk perspectief neer te zetten? Naast de issueanalyse is ook onderzocht welke organisaties hierbij betrokken zijn geweest en de mogelijkheden die zij boden voor publieksinbren

Unraveling transcription regulatory networks by protein-DNA and protein-protein interaction mapping

Metazoan genomes contain thousands of protein-coding and noncoding RNA genes, most of which are differentially expressed, i.e., at different locations or at different times during development, function, or pathology of the organism. Differential gene expression is achieved in part by the action of regulatory transcription factors (TFs) that bind to cis-regulatory elements that are often located in or near their target genes. Each TF likely regulates many targets in the context of intricate transcription regulatory networks. Up to 10% of a genome may encode TFs, but only a handful of these have been studied in detail. Here, I will discuss the different steps involved in the mapping and analysis of transcription regulatory networks, including the identification of network nodes (TFs and their target sequences) and edges (TF-TF dimers and TF-DNA target interactions), integration with other data types, and network properties and emerging principles that provide insights into differential gene expression

Analysis of Photoassociation Spectra for Giant Helium Dimers

We perform a theoretical analysis to interpret the spectra of purely long-range helium dimers produced by photoassociation (PA) in an ultra-cold gas of metastable helium atoms. The experimental spectrum obtained with the PA laser tuned closed to the $2^3S_1\leftrightarrow 2^3P_0$ atomic line has been reported in a previous Letter. Here, we first focus on the corrections to be applied to the measured resonance frequencies in order to infer the molecular binding energies. We then present a calculation of the vibrational spectra for the purely long-range molecular states, using adiabatic potentials obtained from perturbation theory. With retardation effects taken into account, the agreement between experimental and theoretical determinations of the spectrum for the $0_u^+$ purely long-range potential well is very good. The results yield a determination of the lifetime of the $2^3P$ atomic state

Low Energy Skyrmion-Skyrmion Scattering

We study the scattering of Skyrmions at low energy and large separation using the method proposed by Manton of truncation to a finite number of degrees freedom. We calculate the induced metric on the manifold of the union of gradient flow curves, which for large separation, to first non-trivial order is parametrized by the variables of the product ansatz. (presented at the Lake Louise Winter Institute, 1994)Comment: 6 page

Biochemistry and Molecular Biology

Several forward and reverse proteomic approaches are available that can be used to identify interaction partners for a protein of interest. Here we provide methods for identifying interacting partners by the yeast two-hybrid system (a reverse proteomic method) and by tandem immuno-affinity purification of protein complexes combined with mass spectrometry (a forward proteomic method)

Transcription factor functionality and transcription regulatory networks

Now that numerous high-quality complete genome sequences are available, many efforts are focusing on the second genomic code , namely the code that determines how the precise temporal and spatial expression of each gene in the genome is achieved. In this regard, the elucidation of transcription regulatory networks that describe combined transcriptional circuits for an organism of interest has become valuable to our understanding of gene expression at a systems level. Such networks describe physical and regulatory interactions between transcription factors (TFs) and the target genes they regulate under different developmental, physiological, or pathological conditions. The mapping of high-quality transcription regulatory networks depends not only on the accuracy of the experimental or computational method chosen, but also relies on the quality of TF predictions. Moreover, the total repertoire of TFs is not only determined by the protein-coding capacity of the genome, but also by different protein properties, including dimerization, co-factor interactions and post-translational modifications. Here, we discuss the factors that influence TF functionality and, hence, the functionality of the networks in which they operate

Lifetime measurement of the ^3P_2 metastable state of strontium atoms

We have measured the lifetime of the 5s5p ^3P_2 metastable state of strontium atoms by magneto-optically trapping the decayed atoms to the ground state, which allowed sensitive detection of the rare decay events. We found that the blackbody radiation-induced decay was the dominant decay channel for the state at T = 300 K. The lifetime was determined to be 500^{+280}_{-130} s in the limit of zero temperature.Comment: 4 pages, 3 figures, submitted to Physical Review Letter