| 1. |
- Naeye, B, et al.
(author)
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Hemocompatibility of siRNA loaded dextran nanogels
- 2011
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In: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 32:34, s. 9120-9127
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Journal article (peer-reviewed)abstract
- Although the behavior of nanoscopic delivery systems in blood is an important parameter when contemplating their intravenous injection, this aspect is often poorly investigated when advancing from in vitro to in vivo experiments. In this paper, the behavior of siRNA loaded dextran nanogels in human plasma and blood is examined using fluorescence fluctuation spectroscopy, platelet aggregometry, flow cytometry and single particle tracking. Our results show that, in contrast to their negatively charged counterparts, positively charged siRNA loaded dextran nanogels cause platelet aggregation and show increased binding to human blood cells. Although PEGylating the nanogels did not have a significant effect on their interaction with blood cells, single particle tracking revealed that it is necessary to prevent their aggregation in human plasma. We therefore conclude that PEGylated negatively charged dextran nanogels are the most suited for further in vivo studies as they do not aggregate in human plasma and exhibit minimal interactions with blood cells.
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| 2. |
- Werren, John H, et al.
(author)
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Functional and evolutionary insights from the genomes of three parasitoid Nasonia species.
- 2010
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 327:5963, s. 343-8
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Journal article (peer-reviewed)abstract
- We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emerging genetic model, particularly for evolutionary and developmental genetics. Key findings include the identification of a functional DNA methylation tool kit; hymenopteran-specific genes including diverse venoms; lateral gene transfers among Pox viruses, Wolbachia, and Nasonia; and the rapid evolution of genes involved in nuclear-mitochondrial interactions that are implicated in speciation. Newly developed genome resources advance Nasonia for genetic research, accelerate mapping and cloning of quantitative trait loci, and will ultimately provide tools and knowledge for further increasing the utility of parasitoids as pest insect-control agents.
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| 3. |
- Croitoru, MD, et al.
(author)
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Electroluminescence spectra of an STM-tip-induced quantum dot
- 2003
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 68:19
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Journal article (peer-reviewed)abstract
- We analyze the electroluminescence spectrum of an STM-tip-induced quantum dot in a GaAs surface layer. A flexible model has been developed that combines analytical and numerical methods and describes the key features of many-particle states in the STM-tip-induced quantum dot. The dot is characterized by its depth and lateral width, which are experimentally controlled by the bias and current. We find, in agreement with experiment, that increasing the voltage on the STM tip results in a redshift of the electroluminescence peaks, while the peak positions as a function of electron tunneling current through the STM tip reveal a blueshift.
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| 4. |
- Croitoru, MD, et al.
(author)
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Electroluminescence spectra of an STM-tip-induced quantum dot
- 2004
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In: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier. - 1386-9477 .- 1873-1759. ; 21:2-4, s. 270-274
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Journal article (peer-reviewed)abstract
- We analyze the electroluminescence spectrum of an STM-tip-induced quantum dot in a GaAs surface layer. A flexible model has been developed, that combines analytical and numerical methods and describes the key features of many-particle states in the STM-tip-induced quantum dot. The dot is characterized by its depth and lateral width, which are experimentally controlled by the bias and the tunneling current. We find, in agreement with experiment, that increasing voltage on the STM-tip results in a red shift of the electroluminescence peaks, while the peak positions as a function of the electron tunneling current through the STM-tip reveal a blue shift. (C) 2003 Elsevier B.V. All rights reserved.
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| 5. |
- Croitoru, MD, et al.
(author)
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Influence of the characteristics of the STM-tip on the electroluminescence spectra
- 2005
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In: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier. - 1386-9477 .- 1873-1759. ; 27:1-2, s. 13-20
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Journal article (peer-reviewed)abstract
- We analyze the influence of the characteristics of the STM-tip (applied voltage, tip radius) on the electroluminescence spectra from an STM-tip-induced quantum dot. We find that positions of electroluminescence peaks, attributed to the electron-hole recombination in the quantum dot, are very sensitive to the characteristics of the tip, namely increasing voltage on the STM-tip results in a red shift of the electroluminescence peaks, while the peak positions as a function of the tip radius reveal a non-monotonous behavior. (c) 2004 Elsevier B.V. All rights reserved.
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| 6. |
- Goossens, K. V. Y., et al.
(author)
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Molecular Mechanism of Flocculation Self-Recognition in Yeast and Its Role in Mating and Survival
- 2015
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In: mBio. - 2150-7511 .- 2161-2129. ; 6:2, s. 1-16
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Journal article (peer-reviewed)abstract
- We studied the flocculation mechanism at the molecular level by determining the atomic structures of N-Flo1p and N-Lg-Flo1p in complex with their ligands. We show that they have similar ligand binding mechanisms but distinct carbohydrate specificities and affinities, which are determined by the compactness of the binding site. We characterized the glycans of Flo1p and their role in this binding process and demonstrate that glycan-glycan interactions significantly contribute to the cell-cell adhesion mechanism. Therefore, the extended flocculation mechanism is based on the self-interaction of Flo proteins and this interaction is established in two stages, involving both glycan-glycan and protein-glycan interactions. The crucial role of calcium in both types of interaction was demonstrated: Ca-2(+) takes part in the binding of the carbohydrate to the protein, and the glycans aggregate only in the presence of Ca-2(+). These results unify the generally accepted lectin hypothesis with the historically first-proposed "Ca-2(+)-bridge" hypothesis. Additionally, a new role of cell flocculation is demonstrated; i.e., flocculation is linked to cell conjugation and mating, and survival chances consequently increase significantly by spore formation and by introduction of genetic variability. The role of Flo1p in mating was demonstrated by showing that mating efficiency is increased when cells flocculate and by differential transcriptome analysis of flocculating versus nonflocculating cells in a low-shear environment (microgravity). The results show that a multicellular clump (floc) provides a uniquely organized multicellular ultrastructure that provides a suitable microenvironment to induce and perform cell conjugation and mating. IMPORTANCE Yeast cells can form multicellular clumps under adverse growth conditions that protect cells from harsh environmental stresses. The floc formation is based on the self-interaction of Flo proteins via an N-terminal PA14 lectin domain. We have focused on the flocculation mechanism and its role. We found that carbohydrate specificity and affinity are determined by the accessibility of the binding site of the Flo proteins where the external loops in the ligand-binding domains are involved in glycan recognition specificity. We demonstrated that, in addition to the Flo lectin-glycan interaction, glycan-glycan interactions also contribute significantly to cell-cell recognition and interaction. Additionally, we show that flocculation provides a uniquely organized multicellular ultrastructure that is suitable to induce and accomplish cell mating. Therefore, flocculation is an important mechanism to enhance long-term yeast survival.
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| 7. |
- Kemerink, Martijn, et al.
(author)
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Optical properties of a tip-induced quantum dot
- 2001
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In: PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS, PTS I AND II. - : SPRINGER-VERLAG BERLIN. - 3540417788 ; , s. 1183-1184
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Conference paper (peer-reviewed)abstract
- We have performed optical spectroscopy measurements on an STM-tip-induced quantum dot. The dominant confinement in the (hole) quantum dot is in the direction parallel to the tip axis. Electron confinement is achieved by a sub-surface AlGaAs barrier. Current dependent measurements indicate that many-body interactions can cause spectral blue-shifts up to 75 meV.
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| 8. |
- Kemerink, Martijn, et al.
(author)
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Optical properties of a tip-induced quantum dot
- 2001
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In: Applied Physics A. - : Springer Verlag (Germany). - 0947-8396 .- 1432-0630. ; 72, s. S239-S242
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Journal article (peer-reviewed)abstract
- We have performed optical spectroscopy measurements on a STM-tip-induced quantum dot in a GaAs layer. The dominant confinement in the (hole) quantum dot is found to be in the direction parallel to the tip axis. Electron confinement is achieved by a sub-surface AlGaAs barrier. Current-dependent measurements indicate that many-body interactions can cause spectral blueshifts up to 75 meV for a tunneling current of 10 nA. Consequently, a full treatment of the many-body problem is required for an accurate description of this type of system.
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| 9. |
- van Eijsden, R. G. E., et al.
(author)
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A universal fixation method based on quaternary ammonium salts (RNAlater) for omics-technologies: Saccharomyces cerevisiae as a case study
- 2013
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In: Biotechnology Letters. - : Springer Science and Business Media LLC. - 1573-6776 .- 0141-5492. ; 35:6, s. 891-900
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Journal article (peer-reviewed)abstract
- Genomics, transcriptomics, proteomics and fluxomics are powerful omics-technologies that play a major role in today's research. For each of these techniques good sample quality is crucial. Major factors contributing to the quality of a sample is the actual sampling procedure itself and the way the sample is stored directly after sampling. It has already been described that RNAlater can be used to store tissues and cells in a way that the RNA quality and quantity are preserved. In this paper, we demonstrate that quaternary ammonium salts (RNAlater) are also suitable to preserve and store samples from Saccharomyces cerevisiae for later use with the four major omics-technologies. Moreover, it is shown that RNAlater also preserves the cell morphology and the potential to recover growth, permitting microscopic analysis and yeast cell culturing at a later stage.
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