Kennisagenda Geo-informatie: GISsen met beleid

LNV wil méér geo-informatie inzetten bij de ontwikkeling en uitvoering van beleid en beleidsnota’s ruimer voorzien van kaartmateriaal. Dit betekent dat geo-informatie vaker moet worden benut om lokale knelpunten, mogelijkheden en de gevolgen van alternatieve oplossingen inzichtelijk te maken. Om dit te bereiken moet de beschikbaarheid van adequate data en gebruikersvriendelijke en nieuwe GIS-technieken aanmerkelijk verbeteren

Integrated Array Tomography for 3D Correlative Light and Electron Microscopy

Volume electron microscopy (EM) of biological systems has grown exponentially in recent years due to innovative large-scale imaging approaches. As a standalone imaging method, however, large-scale EM typically has two major limitations: slow rates of acquisition and the difficulty to provide targeted biological information. We developed a 3D image acquisition and reconstruction pipeline that overcomes both of these limitations by using a widefield fluorescence microscope integrated inside of a scanning electron microscope. The workflow consists of acquiring large field of view fluorescence microscopy (FM) images, which guide to regions of interest for successive EM (integrated correlative light and electron microscopy). High precision EM-FM overlay is achieved using cathodoluminescent markers. We conduct a proof-of-concept of our integrated workflow on immunolabelled serial sections of tissues. Acquisitions are limited to regions containing biological targets, expediting total acquisition times and reducing the burden of excess data by tens or hundreds of GBs

Integrated Array Tomography for 3D Correlative Light and Electron Microscopy

Volume electron microscopy (EM) of biological systems has grown exponentially in recent years due to innovative large-scale imaging approaches. As a standalone imaging method, however, large-scale EM typically has two major limitations: slow rates of acquisition and the difficulty to provide targeted biological information. We developed a 3D image acquisition and reconstruction pipeline that overcomes both of these limitations by using a widefield fluorescence microscope integrated inside of a scanning electron microscope. The workflow consists of acquiring large field of view fluorescence microscopy (FM) images, which guide to regions of interest for successive EM (integrated correlative light and electron microscopy). High precision EM-FM overlay is achieved using cathodoluminescent markers. We conduct a proof-of-concept of our integrated workflow on immunolabelled serial sections of tissues. Acquisitions are limited to regions containing biological targets, expediting total acquisition times and reducing the burden of excess data by tens or hundreds of GBs.</p

Amphiphilic Zwitterionic Bioderived Block Copolymers from Glutamic Acid and Cholesterol : Ability to Form Nanoparticles and Serve as Vectors for the Delivery of 6-Mercaptopurine

In this work, the straightforward synthesis of amphiphilic zwitterionic bioderived block copolymers (BCPs) using glutamic acid (Glu) and cholesterol (Chol) as building blocks are reported. The previously established Glu-derivative NBoc-Glu-OtBu-methacrylate (NBoc-Glu-OtBu-MA) serves as hydrophobic precursor for the zwitterionic block, while a mostly unexplored cholesteryl-derived methacrylate monomer (Chol-MA) with increased side chain flexibility functions as the hydrophobic block. In the first step, NBoc-Glu-OtBu-MA is polymerized via reversible addition-fragmentation chain-transfer (RAFT) polymerization. Afterward, the linear polymer is chain-extended with Chol-MA, yielding P(NBoc-Glu-OtBu-MA)(n)-b-(Chol-MA)(m) BCPs with varying block ratios. After deprotection under acidic conditions, polymers with a block weight ratio of 87:13 (Glu-OH-MA:Chol-MA) readily assemble into polymeric nanoparticles (NPs) of a desirable size below 100 nm diameter, making them good candidates for biomedical applications. The experimental results are supported using computations of the partition coefficients and machine learning models for the prediction of the polymer densities of the different BCPs. In addition, high (up to 20 wt.%) loading of the hydrophobic anti-cancer drug 6-mercaptopurine (6-MP) is achieved in these NPs during the assembly process. The cytostatic activity of 6-MP NPs is demonstrated in vitro on MDA-MB-231 breast cancer cells. These results emphasize the potential of amphiphilic zwitterionic bioderived NPs for the delivery of hydrophobic drugs

Imaging the essential role of spin-fluctuations in high-Tc superconductivity

We have used scanning tunneling spectroscopy to investigate short-length electronic correlations in three-layer Bi2Sr2Ca2Cu3O(10+d) (Bi-2223). We show that the superconducting gap and the energy Omega_dip, defined as the difference between the dip minimum and the gap, are both modulated in space following the lattice superstructure, and are locally anti-correlated. Based on fits of our data to a microscopic strong-coupling model we show that Omega_dip is an accurate measure of the collective mode energy in Bi-2223. We conclude that the collective mode responsible for the dip is a local excitation with a doping dependent energy, and is most likely the (pi,pi) spin resonance.Comment: 4 pages, 4 figure

Optical shield: measuring viscosity of turbid fluids using optical tweezers

The viscosity of a fluid can be measured by tracking the motion of a suspended micron-sized particle trapped by optical tweezers. However, when the particle density is high, additional particles entering the trap compromise the tracking procedure and degrade the accuracy of the measurement. In this work we introduce an additional Laguerre–Gaussian, i.e. annular, beam surrounding the trap, acting as an optical shield to exclude contaminating particles

Effect of Disorder on Ultrafast Exciton Dynamics Probed by Single Molecule Spectroscopy

We present a single-molecule study unraveling the effect of static disorder on the vibrational-assisted ultrafast exciton dynamics in multichromophoric systems. For every single complex, we probe the initial exciton relaxation process by an ultrafast pump-probe approach and the coupling to vibrational modes by emission spectra, while fluorescence lifetime analysis measures the amount of static disorder. Exploiting the wide range of disorder found from complex to complex, we demonstrate that static disorder accelerates the dephasing and energy relaxation rate of the exciton

Responsive glyco-poly(2-oxazoline)s: synthesis, cloud point tuning, and lectin binding

A new sugar-substituted 2-oxazoline monomer was prepared using the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. Its copolymerization with 2-ethyl-2-oxazoline as well as 2-(dec-9-enyl)-2-oxazoline, yielding well-defined copolymers with the possibility to tune the properties by thiol-ene "click" reactions, is described. Extensive solubility studies on the corresponding glycocopolymers demonstrated that the lower critical solution temperature behavior and pH-responsiveness of these copolymers can be adjusted in water and phosphate-buffered saline (PBS) depending on the choice of the thiol. By conjugation of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose and subsequent deprotection of the sugar moieties, the hydrophilicity of the copolymer could be increased significantly, allowing a cloud-point tuning in the physiological range. Furthermore, the binding capability of the glycosylated copoly(2-oxazoline) to concanavalin A was investigated

Antimicrobial peptide capsids of de novo design

The spread of bacterial resistance to antibiotics poses the need for antimicrobial discovery. With traditional search paradigms being exhausted, approaches that are altogether different from antibiotics may offer promising and creative solutions. Here, we introduce a de novo peptide topology that-by emulating the virus architecture-assembles into discrete antimicrobial capsids. Using the combination of high-resolution and real-time imaging, we demonstrate that these artificial capsids assemble as 20-nm hollow shells that attack bacterial membranes and upon landing on phospholipid bilayers instantaneously (seconds) convert into rapidly expanding pores causing membrane lysis (minutes). The designed capsids show broad antimicrobial activities, thus executing one primary function-they destroy bacteria on contact

Coherent source and connectivity analysis on simultaneously measured EEG and MEG data during isometric contraction

The most well-known non-invasive electric and magnetic field measurement modalities are the electroencephalography (EEG) and magnetoencephalography (MEG). The first aim of the study was to implement the recently developed realistic head model which uses an integrative approach for both the modalities. The second aim of this study was to find the network of coherent sources and the modes of interactions within this network during isometric contraction (ISC) at (15-30 Hz) in healthy subjects. The third aim was to test the effective connectivity revealed by both the modalities analyzing them separately and combined. The Welch periodogram method was used to estimate the coherence spectrum between the EEG and the electromyography (EMG) signals followed by the realistic head modelling and source analysis method dynamic imaging of coherent sources (DICS) to find the network of coherent sources at the individual peak frequency within the beta band in healthy subjects. The last step was to identify the effective connectivity between the identified sources using the renormalized partial directed coherence method. The cortical and sub-cortical network comprised of the primary sensory motor cortex (PSMC), secondary motor area (SMA), and the cerebellum (C). The cortical and sub-cortical network responsible for the isometric contraction was similar in both the modalities when analysing them separately and combined. The SNR was not significantly different between the two modalities separately and combined. However, the coherence values were significantly higher in the combined modality in comparison to each of the modality separately. The effective connectivity analysis revealed plausible additional connections in the combined modality analysis