SEM-EDAX investigations of use-related microstructural changes in an ammonia synthesis catalyst

Egyházi, T.; Scholtz, József; Beskov, V. S.

doi:10.1007/bf02069592

Cited by 8 publications

(3 citation statements)

References 2 publications

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“…By scanning electron microscopy and energy dispersive X-ray analysis it was found that K segregates to the outer part of the catalyst particles with storage and prolonged use [69].…”

Section: Potassiummentioning

confidence: 99%

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

Stoltze

1995

Ammonia

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“…By scanning electron microscopy and energy dispersive X-ray analysis it was found that K segregates to the outer part of the catalyst particles with storage and prolonged use [69].…”

Section: Potassiummentioning

confidence: 99%

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

Stoltze

1995

Ammonia

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“…Energy dispersive X-ray analysis (EDAX) was performed to identify and quantify the elemental composition on the surfaces with the help of a FEI scanning electron microscope (Model Quanta 200, USA). Micrographs were taken at 20 keV beam acceleration voltages with analysis time of 100 s. The ZAF program, which does not require the presence of any internal standard, was used to calculate the elemental composition of the surface [35,36].…”

Section: Scanning Electron Microscopy and Energy Dispersive X-ray Anamentioning

confidence: 99%

Surface Engineering of Polycaprolactone by Biomacromolecules and their Blood Compatibility

et al. 2010

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Improving blood compatibility of biodegradable polymers is an area of intensive research in blood contacting devices. In this study, curdlan sulphate and heparin-modified poly (caprolactone) (PCL) hybrids were developed by physically entrapping these molecules on the PCL surface. This modification technique was performed by reversible gelation of the PCL surface region following exposure to a solvent and nonsolvent mixture. The presence of these biomacromolecules on the PCL surface was verified by atomic force microscopy (AFM) and scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDAX) analysis, while wettability of the films was investigated by dynamic contact angle measurements. The blood compatibilities of the surface-modified films were examined using in vitro platelet and leukocyte adhesion and thrombus formation. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response to the modified surface by quantifying mRNA expression levels of proinflammatory cytokines namely TNF-α and IL-1β using real-time polymerase chain reaction (RT-PCR). A lower platelet and leukocyte adhesion and activation was observed on the modified films incubated with whole human blood for 2 h. The thrombus formation on the PCL was significantly decreased upon immobilization of both curdlan sulphate (39%, *p<0.05) and heparin (28%, *p<0.01) when compared to bare PCL (80%). All of these results revealed that improved blood compatibility was obtained by surface entrapment of both curdlan sulphate (CURS) and heparin (HEP) onto PCL films. Both PCL-CURS and PCL-HEP films reduced RAW 264.7 macrophage cell adhesion (*p<0.05) with respect to the base unmodified PCL. The cellular inflammatory response was suppressed on the modified substrates. The mRNA expression levels of proinflammmatory cytokines (TNF-α and IL-1β) were upregulated on bare PCL, while it was significantly lower on PCL-CURS and PCL-HEP substrates (**p<0.001). Thus, this biomacromolecule entrapment process can be applied on PCL in order to achieve improved blood compatibility and reduced inflammatory host response for its future blood contacting applications.

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“…Energy dispersive X-ray analysis (EDAX) was performed to identify and quantify the elemental composition on the surfaces with the help of a FEI scanning electron microscope (SEM) (Model Quanta, USA). Micrographs were taken at 20 keV beam acceleration voltages with analysis time of 100 s. The ZAF program, which does not require the presence of any internal standard, was used to calculate the elemental composition of the surface [28,29].…”

Section: Scanning Electron Microscopy and Energy Dispersive X-ray Anamentioning

confidence: 99%

The Biocompatibility of Sulfobetaine Engineered Poly (Ethylene Terephthalate) by Surface Entrapment Technique

et al. 2009

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Sulfobetaine-modified poly(ethylene terephthalate) (PET) systems were created by physically entrapping the zwitterionic species on the PET surface. The presence of the sulfobetiane molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The blood compatibility of the modified films was evaluated by platelet adhesion in human platelet-rich plasma (PRP). The adhesion and inflammatory response of Mouse RAW 264.7 macrophage cells were studied. The surface induced cellular inflammatory response was determined by quantifying the expression levels of proinflammatory cytokines namely TNF-alpha and IL-1beta by measuring their mRNA profiles in the cells using real time polymerase chain reaction normalized to the housekeeping gene GAPDH. L-929 fibroblast cells were used to assess the propensity of the materials to support the fibroblast cell adhesion. A lower platelet adhesion and activation were observed on the sulfobetaine-modified PET film incubated in PRP after 2h when compared to control. The modified film reduced cellular adhesion events ( p<0.05) with respect to the base material, which could be linked to the reduced protein adsorption observed on this surface. The cellular inflammatory response was suppressed on sulfobetaine-modified substrate. Expression levels of pro-inflammmatory cytokines (TNF-alpha and IL-1beta) was found to be upregulated on bare PET, while it was significantly lower on modified PET ( p<0.001). Thus the sulfobetaine entrapment process can be applied on PET in order to achieve low biointeractions and reduced inflammatory host response for various biomedical and biotechnological applications.

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SEM-EDAX investigations of use-related microstructural changes in an ammonia synthesis catalyst

Cited by 8 publications

References 2 publications

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

Surface Engineering of Polycaprolactone by Biomacromolecules and their Blood Compatibility

The Biocompatibility of Sulfobetaine Engineered Poly (Ethylene Terephthalate) by Surface Entrapment Technique

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