Ni-Cr-Co alloy ureteral stent: Scanning electron microscopy and elemental analysis characterization after long-term indwelling

Author(s):  
Valentina Cauda ◽  
Cristian Fiori ◽  
Furio Cauda
Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1550 ◽  
Author(s):  
So Young Kim ◽  
Younghyun Cho ◽  
Sang Wook Kang

In this study, we investigated a poly(ether-block-amide)-5513 (PEBAX-5513)/AgBF4/1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) composite membrane, which is expected to have a high stabilizing effect on the Ag+ ions functioning as olefin carriers in the amide group. Poly(ethylene oxide) (PEO) only consists of ether regions, whereas the PEBAX-5513 copolymer contains both ether and amide regions. However, given the brittle nature of the amide, the penetration of BMIMBF4 remains challenging. The nanoparticles did not stabilize after their formation in the long-term test, thereby resulting in a poor performance compared to previous experiments using PEO as the polymer (selectivity 3; permeance 12.3 GPU). The properties of the functional groups in the polymers were assessed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis, which confirmed that the properties endowed during the production of the film using the ionic liquid can impact the performance.


2015 ◽  
Vol 21 (S3) ◽  
pp. 401-402
Author(s):  
Gabriel Herrera-Perez ◽  
Xóchitl Sofia Ramirez-Gómez ◽  
Rafael Vargas-Bernal ◽  
Esmeralda Rodríguez-Miranda

2012 ◽  
Vol 9 (75) ◽  
pp. 2551-2562 ◽  
Author(s):  
Marjorie S. Austero ◽  
Amalie E. Donius ◽  
Ulrike G. K. Wegst ◽  
Caroline L. Schauer

Chitosan (CS), the deacetylated form of chitin, the second most abundant, natural polysaccharide, is attractive for applications in the biomedical field because of its biocompatibility and resorption rates, which are higher than chitin. Crosslinking improves chemical and mechanical stability of CS. Here, we report the successful utilization of a new set of crosslinkers for electrospun CS. Genipin, hexamethylene-1,6-diaminocarboxysulphonate (HDACS) and epichlorohydrin (ECH) have not been previously explored for crosslinking of electrospun CS. In this first part of a two-part publication, we report the morphology, determined by field emission scanning electron microscopy (FESEM), and chemical interactions, determined by Fourier transform infrared microscopy, respectively. FESEM revealed that CS could successfully be electrospun from trifluoroacetic acid with genipin, HDACS and ECH added to the solution. Diameters were 267 ± 199 nm, 644 ± 359 nm and 896 ± 435 nm for CS–genipin, CS–HDACS and CS–ECH, respectively. Short- (15 min) and long-term (72 h) dissolution tests (T 600 ) were performed in acidic, neutral and basic pHs (3, 7 and 12). Post-spinning activation by heat and base to enhance crosslinking of CS–HDACS and CS–ECH decreased the fibre diameters and improved the stability. In the second part of this publication, we report the mechanical properties of the fibres.


1979 ◽  
Vol 83 (1) ◽  
pp. 260-265 ◽  
Author(s):  
M Chinkers ◽  
J A McKanna ◽  
S Cohen

The morphological effects of epidermal growth factor (EGF) on human carcinoma cells A-431 have been examined by scanning electron microscopy. These flat polygonal cells normally exhibit only small membrane folds, but show extensive ruffling and extension of filopodia within 5 min of exposure to EGF at 37 degrees C. This ruffling activity is transient, subsiding within another 5--15 min, but several other changes in surface morphology follow. Within the first hour of exposure to the hormone, the cell surface becomes exceedingly smooth and the nuclei seem to protrude above the plane of the otherwise thin monolayer, giving the cells a "fried egg" appearance. Cells at the edges of colonies gradually retract from the substrate, leading to reorganization, by 12 h, of the monolayer into multilayered colonies. EGF thus induces both rapid and long-term alterations in the morphology of these epidermoid cells.


2007 ◽  
Vol 2007 ◽  
pp. 1-10 ◽  
Author(s):  
Kris N. J. Stevens ◽  
Yvette B. J. Aldenhoff ◽  
Frederik H. van der Veen ◽  
Jos G. Maessen ◽  
Leo H. Koole

Extended use of cardiopulmonary bypass (CPB) systems is often hampered by thrombus formation and infection. Part of these problems relates to imperfect hemocompatibility of the CPB circuitry. The engineering of biomaterial surfaces with genuine long-term hemocompatibility is essentially virgin territory in biomaterials science. For example, most experiments with the well-known Chandler loop model, for evaluation of blood-biomaterial interactions under flow, have been described for a maximum duration of 2 hours only. This study reports a systematic evaluation of two commercial CPB tubings, each with a hemocompatible coating, and one uncoated control. The experiments comprised (i) testing over 5 hours under flow, with human whole blood from 4 different donors; (ii) measurement of essential blood parameters of hemocompatibility; (iii) analysis of the luminal surfaces by scanning electron microscopy and thrombin generation time measurements. The dataset indicated differences in hemocompatibility of the tubings. Furthermore, it appeared that discrimination between biomaterial coatings can be made only after several hours of blood-biomaterial contact. Platelet counting, myeloperoxidase quantification, and scanning electron microscopy proved to be the most useful methods. These findings are believed to be relevant with respect to the bioengineering of extracorporeal devices that should function in contact with blood for extended time.


1995 ◽  
Vol 7 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Salah A EI-Shatoury

Coordination polymers of [2,2'-(ethandiylidenedinitrilo) diphenol) have been prepared with the metal ions Cu(II), Ni(1I) and Cr(III). They were characterized by elemental analysis, IR and electronic spectra. The metal content in all polymers was found to be consistent with a 1:1 (metal:ligand) stoichiometry. The thermal behaviour of these coordination polymers has been studied by thermogravimetric and DSC analyses in air up to 500 C. The crystallinity of the formed polymers was determined by x-ray analysis. The morphological structures of these polymers were determined by scanning electron microscopy.


2006 ◽  
Vol 17 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Douglas H. Ubelaker ◽  
Karen E. Stothert

AbstractThe relationship between Andean coca use and dental deposits is explored through the use of scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Elemental analyses of samples of large dental deposits from archeologically recovered skeletons from Ecuador dating between 500 B.C. and A.D. 1532 are compared with those of normal calculus deposits of individuals from North America (modern and precontact), of normal tooth structure and of samples of alkali recovered from Ecuadorian artifacts thought to have been employed in coca use. Spectral analysis revealed homogeneity among all dental samples (deposits and structure) and that they are distinct from the elemental pattern revealed in the analysis of the artifact alkalis.


1974 ◽  
Vol 22 (4) ◽  
pp. 647 ◽  
Author(s):  
JJ Mott ◽  
PW Tynan

The anatomy of the hull directly over the embryo was examined by light and electron microscopy in long-term dormant and non-dormant grains of A. contorta. A lipid-containing layer was noted, covering the surface of the inner epidermis of the hull, and examination by scanning electron microscopy showed that although the layer was intact in all dormant grain examined, it was fractured in non-dormant grain. A definitive statement on the function of these cracks is not possible, but they appear to be an anatomical change leading to increased gas permeability of the hull of non-dormant grains.


Sign in / Sign up

Export Citation Format

Share Document