X-ray Photoelectron Spectroscopy for Wheat Powders: Measurement of Surface Chemical Composition

2011 ◽  
Vol 59 (5) ◽  
pp. 1527-1540 ◽  
Author(s):  
Moustafa Saad ◽  
Claire Gaiani ◽  
Martine Mullet ◽  
Joel Scher ◽  
Bernard Cuq
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Surface Chemical ◽  
X Ray ◽  
Surface Chemical Composition

scholarly journals Applying Cryo-X-ray Photoelectron Spectroscopy to Study the Surface Chemical Composition of Fungi and Viruses

2021 ◽  
Vol 9 ◽  
Author(s):  
Andrey Shchukarev ◽  
Emelie Backman ◽  
Samuel Watts ◽  
Stefan Salentinig ◽  
Constantin F. Urban ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Biological Systems ◽  
Building Blocks ◽  
Model Organisms ◽  
Surface Chemical ◽  
Surface Layers ◽  
Xps Spectra ◽  
X Ray ◽  
Surface Chemical Composition

Interaction between microorganisms and their surroundings are generally mediated via the cell wall or cell envelope. An understanding of the overall chemical composition of these surface layers may give clues on how these interactions occur and suggest mechanisms to manipulate them. This knowledge is key, for instance, in research aiming to reduce colonization of medical devices and device-related infections from different types of microorganisms. In this context, X-ray photoelectron spectroscopy (XPS) is a powerful technique as its analysis depth below 10 nm enables studies of the outermost surface structures of microorganism. Of specific interest for the study of biological systems is cryogenic XPS (cryo-XPS). This technique allows studies of intact fast-frozen hydrated samples without the need for pre-treatment procedures that may cause the cell structure to collapse or change due to the loss of water. Previously, cryo-XPS has been applied to study bacterial and algal surfaces with respect to their composition of lipids, polysaccharides and peptide (protein and/or peptidoglycan). This contribution focuses onto two other groups of microorganisms with widely different architecture and modes of life, namely fungi and viruses. It evaluates to what extent existing models for data treatment of XPS spectra can be applied to understand the chemical composition of their very different surface layers. XPS data from model organisms as well as reference substances representing specific building blocks of their surface were collected and are presented. These results aims to guide future analysis of the surface chemical composition of biological systems.

scholarly journals Surface Chemical Composition of Size-Fractionated Urban Walkway Aerosols Determined by X-Ray Photoelectron Spectroscopy

2013 ◽  
Vol 47 (10) ◽  
pp. 1118-1124 ◽  
Author(s):  
Wenjuan Cheng ◽  
Lu-Tao Weng ◽  
Yongjie Li ◽  
Arthur Lau ◽  
Chak K. Chan ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Surface Chemical ◽  
X Ray ◽  
Surface Chemical Composition

scholarly journals Study of surface chemical composition of oxide nanostructures by X-ray photoelectron spectroscopy

2020 ◽  
Vol 1658 ◽  
pp. 012034
Author(s):  
S S Nalimova ◽  
Z V Shomakhov ◽  
A A Bobkov ◽  
A A Ryabko ◽  
Z Kh Kalazhokov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Surface Chemical ◽  
X Ray ◽  
Surface Chemical Composition ◽  
Oxide Nanostructures

scholarly journals Surface Texture of Microcrystalline Tunnel-Structured Manganese(IV) Oxides: Nitrogen Sorptiometry and Electron Microscopy Studies

2002 ◽  
Vol 20 (7) ◽  
pp. 619-632 ◽  
Author(s):  
A.A. Ali ◽  
F.A. Al-Sagheer ◽  
M.I. Zaki
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Surface Texture ◽  
Particle Morphology ◽  
High Resolution Electron Microscopy ◽  
Surface Chemical ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Surface Chemical Composition ◽  
Resolution Electron

Three different modifications of manganese(IV) oxide, viz. cryptomelane, nsutite and todorokite-like, were synthesized by hydrothermal methods. The bulk chemical composition, phase composition, crystalline structure and particle morphology of the resulting materials were determined by thermogravimetry, atomic absorption spectroscopy, X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The surface chemical composition, texture and structure were assessed using X-ray photoelectron microscopy, nitrogen sorptiometry and high-resolution electron microscopy. The results highlighted the hydrothermal conditions under which such tunnel-structured modifications of manganese(IV) oxide can be successfully synthesized. Moreover, they revealed that (i) the bulk was microcrystalline, (ii) the crystallites were either fibrils (cryptomelane and nsutite) or rod-like (todorokite) with low-index exposed facets, (iii) the surface chemical composition mostly reflected that of the bulk and (iv) the surface texture was linked with high specific areas, slit-shaped mesopores associated with particle interstices and micropores which allowed surface accessibility to the bulk tunnels of the test oxides. The application of such test oxides as shape-selective oxidation catalysts appears worthy of investigation.

Zooming in on surface chemical composition of soil microaggregates – Is there an effect of plants (Festuca)?

2021 ◽  
Author(s):  
Susanne K Woche ◽  
Stefan Dultz ◽  
Robert Mikutta ◽  
Klaus Kaiser ◽  
Georg Guggenberger
Keyword(s):  
Contact Angle ◽  
Organic Matter ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Bare Soil ◽  
Organic N ◽  
Initial Contact ◽  
Surface Chemical ◽  
Surface Chemical Composition ◽  
Fresh Organic Matter

<p>Formation of soil microaggregates (SMA) is a surface-driven process and depends on mineral cementing and organic gluing agents. Yet, the role of plants in soil microaggregation by input of fresh organic matter remains little understood. In a mesocosm experiment silty Luvisol topsoil (<250 µm; original soil material) was incubated in absence (bare soil) and presence of plants (Festuca) and water-stable free and occluded SMA were isolated after 4, 12, and 30 weeks and investigated for the surface chemical composition by X-ray photoelectron spectroscopy (XPS) and for wetting properties by contact angle determination.</p><p>Compared to the original soil, the surfaces of both free and occluded SMA tended to smaller O and larger C contents, thus a smaller O/C ratio, along with a slight increase in initial contact angle from about 10° (original soil) to about 20° (SMA). The O/C ratio decreased slightly further from 4 to 12 weeks, especially for bare soil without plants. Slightly greater C contents were detected for occluded than for free SMA, probably hinting at higher retention of organic matter on surfaces of microaggregates entrained in larger soil structures. For bare soil, a slightly greater N content was observed for free SMA while in the presence of Festuca free and occluded SMA had same N contents.</p><p>Regardless of the presence of Festuca, C speciation indicated a lower proportion (in % of total C) of C=O/O-C-O and a higher proportion of C - C/C -  H species for occluded than for free SMA, probably indicating less altered organic matter at the surfaces of occluded SMA. While the proportion of C=O/O-C-O species slightly decreased, that of C- C/C-H species slightly increased towards the end of the incubation. This may hint at some preferences in microbial respiration with respect to C compounds and formation of microbial metabolites. From N speciation a higher ratio between protonated and non-protonated organic N species (N<sub>p</sub>/N<sub>np</sub>) was indicated for Festuca than for bare soil after 4 and for 30 weeks of incubation, i.e., the presence of plants seems to impact N compounds present. The N<sub>p</sub>/N<sub>np </sub>ratio tended to decrease after 30 weeks compared to 4 weeks for both treatments, hinting on changes in N species present.</p><p>In summary, aside some effect on N species present, results indicate rather incubation and SMA origin (free, occluded) than the presence of plants (Festuca) to impact surface chemical composition of the tested SMA. This suggests no defined contribution of plants and their products to formation of 250-53 µm-sized SMA.</p>

Effects of X-ray radiation on the surface chemical composition of plasma deposited thin fluorocarbon films

2008 ◽  
Vol 93 (3) ◽  
pp. 700-706 ◽  
Author(s):  
M. Himmerlich ◽  
V. Yanev ◽  
A. Opitz ◽  
A. Keppler ◽  
J.A. Schaefer ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Surface Chemical ◽  
X Ray ◽  
Fluorocarbon Films ◽  
Surface Chemical Composition
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