Search results for " microscopy"
showing 10 items of 1617 documents
Force measurements and tip shape approximation with the atomic force microscope
2011
The Atomic Force Microscope (AFM) is an instrument with huge impact on modern research in the nanosciences and in nanotechnology. In AFM, a tip which is sharp on a scale of nanometers or tens of nanometers, is scanning along the surface which is imaged. A few among the large numbers of factors that potentially affect the interaction between the tip and the surface were studied in the experimental work that form this Thesis. Friction and elasticity measurements with AFM and the approximation of the tip shape are discussed. Also the contribution of the imaging environment is studied. A commercial AFM was modified into a so called environmental-AFM (env- AFM) , where the imaging conditions, su…
Resolving Bio-Nano Interactions of E.coli Bacteria-Dragonfly Wing Interface with Helium Ion and 3D-Structured Illumination Microscopy to Understand B…
2020
Obtaining a comprehensive understanding of the bactericidal mechanisms of natural nanotextured surfaces is crucial for the development of fabricated nanotextured surfaces with efficient bactericidal activity. However, the scale, nature, and speed of bacteria-nanotextured surface interactions make the characterization of the interaction a challenging task. There are currently several different opinions regarding the possible mechanisms by which bacterial membrane damage occurs upon interacting with nanotextured surfaces. Advanced imaging methods could clarify this by enabling visualization of the interaction. Charged particle microscopes can achieve the required nanoscale resolution but are …
New Polylactic Acid Composites Reinforced with Artichoke Fibers
2015
In this work, artichoke fibers were used for the first time to prepare poly(lactic acid) (PLA)-based biocomposites. In particular, two PLA/artichoke composites with the same fiber loading (10% w/w) were prepared by the film-stacking method: the first one (UNID) reinforced with unidirectional long artichoke fibers, the second one (RANDOM) reinforced by randomly-oriented long artichoke fibers. Both composites were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. The morphology of the fracture surfaces was analyzed through scanning electron microscopy (SEM). Moreover, a theoretical model, i.e., Hill's method, was used to fit the experimental Young's modu…
Effects of tributyltin(IV) chloride on fertilization ofStyela plicata(Ascidiacea: Tunicata): II. Scanning and transmission electron microscopy studies
2003
The morphological aspects of Styela plicata fertilization after treatment with tributyltin(IV) chloride are described by means of scanning and transmission electron microscopy investigations. Alterations have been shown both on female and male gametes; spermatozoa, all the egg envelopes and the mitochondria of the egg cortical cytoplasm are modified in relation to incubation time. As a consequence, the damage to gametes blocks sperm–egg interaction and fertilization does not occur. Copyright © 2003 John Wiley & Sons, Ltd.
Surface Modification of Porous Polyethylene Implants with an Albumin-Based Nanocarrier-Release System
2021
Background: Porous polyethylene (PPE) implants are used for the reconstruction of tissue defects but have a risk of rejection in case of insufficient ingrowth into the host tissue. Various growth factors can promote implant ingrowth, yet a long-term gradient is a prerequisite for the mediation of these effects. As modification of the implant surface with nanocarriers may facilitate a long-term gradient by sustained factor release, implants modified with crosslinked albumin nanocarriers were evaluated in vivo. Methods: Nanocarriers from murine serum albumin (MSA) were prepared by an inverse miniemulsion technique encapsulating either a low- or high-molar mass fluorescent cargo. PPE implants …
Structure of keyhole limpet hemocyanin type 1 (KLH1) at 15 Å resolution by electron cryomicroscopy and angular reconstitution † 1 †This article is de…
1997
Abstract A three-dimensional reconstruction of keyhole limpet hemocyanin type 1 (KLH1) has been obtained using electron cryomicroscopy at liquid helium temperatures and single particle image processing. The use of a high-contrast embedding medium, 1% (w/v) glucose and 2% (w/v) ammonium molybdate (pH 7.0), enables high-resolution electron micrographs to be recorded close to focus, i.e. with excellent transfer of high-resolution information, while maintaining enough image contrast to localise the individual macromolecules in the images. When low-pass filtered to ∼45 A resolution, the new 15 A resolution reconstruction is very similar to the earlier reconstructions of gastropodan hemocyanins o…
Labeling of Single Cells in the Central Nervous System of <em>Drosophila melanogaster</em>
2013
In this article we describe how to individually label neurons in the embryonic CNS of Drosophila melanogaster by juxtacellular injection of the lipophilic fluorescent membrane marker DiI. This method allows the visualization of neuronal cell morphology in great detail. It is possible to label any cell in the CNS: cell bodies of target neurons are visualized under DIC optics or by expression of a fluorescent genetic marker such as GFP. After labeling, the DiI can be transformed into a permanent brown stain by photoconversion to allow visualization of cell morphology with transmitted light and DIC optics. Alternatively, the DiI-labeled cells can be observed directly with confocal microscopy, …
Immunological and ultrastructural characterization of spirotrichonymphid flagellates from Reticulitermes grassei and R. flavipes (syn. R. santonensis…
2006
AbstractFive species of spirotrichonymphids representing three genera have been studied by light and immunofluorescence microscopy, and by transmission electron microscopy. The genus Spirotrichonympha, represented by S. flagellata from Reticulitermes grassei, is characterized by a compound axostyle composed of several fibers or subaxostyles. The genus Spironympha, represented by S. kofoidi from Reticulitermes flavipes (syn. R. santonensis) and by the two new species S. verticis and S. lanceata, is characterized by flagellar lines restricted to the anterior area and a simple, tubular axostyle. Spironympha verticis and S. lanceata are mainly distinguished by ultrastructural details of their f…
Protection of living yeast cells by micro-organized shells of natural polyelectrolytes
2015
International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…
The Candida albicans cell wall-associated glyceraldehyde-3-phosphate dehydrogenase activity increases in response to starvation and temperature upshi…
2002
We have determined the effect of environmental factors (mild thermal upshift and starvation) on the Candida albicans cell wall-associated glyceraldehyde-3-phosphate dehydrogenase (cwGAPDH) activity. Temperature upshift (from 28 to 37 degrees C) and/ or starvation (at 28 or 37 degrees C in water) of exponentially growing yeast cells caused an increase in cwGAPDH activity (3 to 5-, and 7 to 8-fold, respectively). This increase in activity did not correlate with an increase in the amount of cwGAPDH protein present, as determined by flow cytometry, immunoelectron microscopy and Western-blotting. These results indicate that thermal upshift and starvation cause an activation of the cwGAPDH in C. …