Peculiar opportunities given by XPS spectroscopy for the clinician

Brigiano, Flavio Siro; Bazin, Dominique; Tielens, Frederik

doi:10.5802/crchim.154

Cited by 6 publications

(3 citation statements)

References 153 publications

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“…The results were in agreement with Rowley et al (2021). The position of the most intense Ca2p3/2 peak is found to be strongly dependent on the local chemical environment of the Ca atom (Brigiano et al, 2022). The Ca2p3/2 core level BE position of calcite is known to appear at 346.5 (Ni & Ratner, 2008) that confirms significantly higher precipitation of calcite in sand specimens prepared using 2% (m/v) SF cross‐linked with genipin compared to other specimens.…”

Section: Resultsmentioning

confidence: 99%

Self‐assembled silk fibroin cross‐linked with genipin supplements microbial carbonate precipitation in building material

Li,

Achal

2023

Environ Microbiol Rep

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The process of microbially induced carbonate precipitation (MICP) is known to effectively improve engineering properties of building materials and so does silk fibroin (SF). Thus, in this study, an attempt was taken to see the improvement in sand, that is, basic building material coupled with MICP and SF. Urease producing Bacillus megaterium was utilized for MICP in Nutri‐Calci medium. To improve the strength of SF itself in bacterial solution, it was cross‐linked with genipin at the optimized concentration of 3.12 mg/mL. The Fourier transform infrared (FTIR) spectra confirmed the crosslinking of SF with genipin in bacterial solution. In order to understand how such cross‐linking can improve engineering properties, sand moulds of 50 mm3 dimension were prepared that resulted in 35% and 55% more compressive strength than the one prepared with bacterial solution with SF and bacterial solution only, respectively with higher calcite content in former one. The FTIR, SEM, x‐ray powder diffraction spectrometry and x‐ray photoelectron spectroscopy analyses confirmed higher biomineral precipitation in bacterial solution coupled with genipin cross‐linked SF. As the process of MICP is proven to replace cement partially from concrete without negatively influence mechanical properties, SF cross‐linked with genipin can provide additional significance in developing low‐carbon cement‐based composites.

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Section: Resultsmentioning

confidence: 99%

Self‐assembled silk fibroin cross‐linked with genipin supplements microbial carbonate precipitation in building material

Li,

Achal

2023

Environ Microbiol Rep

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“…Generally, X-ray spectral simulations of crystals fall into two categories, based on periodic cells − or cluster models, ,− both of which are performed mainly with the density functional theory (DFT). The cluster model way treats a crystal as a “big molecule”, which avoids the spurious charge problem in periodic calculations caused by replicas of core holes in different cells.…”

Section: Introductionmentioning

confidence: 99%

A QM/MM Study on the X-ray Spectra of Organic Proton Transfer Crystals of Isonicotinamides

Zhang

Wang

et al. 2022

J. Phys. Chem. C

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Proton transfer (PT) in organic crystals creates localized charges and strong hydrogen bonding (HB), making the self-consistent field (SCF) calculation of core-ionized and core-excited states challenging. Today most corresponding X-ray spectral measurements are interpreted based on empirical fitting and/or chemical intuitions. Here we present a systematic quantum mechanical/molecular mechanical (QM/MM) study of N 1s X-ray photoelectron (XPS) and absorption (XAS) spectra of three isonicotinamide (IN)-based organic crystals with full (1), half (2), and no (3) protonations. A complete picture of the structure–spectroscopy relation in different crystal environments was provided, and assignments to three unprotonated (pyridinic, p; amide, a 1 and a 2) sites and one protonated (pyridinic, h) N site were clearly made. We found that including distant residues as natural population analysis (NPA) point charges can effectively enhance the SCF convergence of the core states. The size of the QM part was tuned, and with some 140–170 atoms we achieved spectral convergence that can represent the infinite crystal. At the crystal structures, simulated relative binding energies deviate ≤0.3 eV to experiments. Simulated XAS spectra agree well with experiments, and with molecular orbital analysis we interpreted the π* structures as hybrid local excitation and charge transfer states (πLE–CT *) or pure LE states (πLE *). Analyses on both spectra helped understand the PT and HB nature in such organic crystals, and a debate in XPS interpretation of 3 was resolved and its XAS assignment corrected. Further, to model the dynamical effect of the proton in 2, XPS/XAS spectra were evaluated at snapshots with varying N–H distances. A continuous picture illustrates the sensitive influence of proton position to both spectra. Reduction of the N–H distance by only 0.2 Å from the crystal structure (1.1 Å) excellently reproduced both spectra. This perturbation phenomenologically models effects of vibration from the equilibrium crystal structure and environmental temperature and pressure factors.

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“…Historically, theoretical XPS studies on materials mainly focused on relative BEs. , In recent years, new theoretical methods − have been developed to calculate absolute BEs, based on large clusters and/or periodic cells. One such method is the cluster-periodic method (CPM), , which predicts absolute BEs referenced to the Fermi level and allows for direct comparisons with experimental results.…”

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confidence: 99%

Global Impact and Balancing Act: Deciphering the Effect of Fluorination on B 1s Binding Energies in Fluorinated h-BN Nanosheets

Xiao,

Zhang,

Wang

et al. 2024

Precision Chemistry

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X-ray photoelectron spectroscopy (XPS) is an important characterization tool in the pursuit of controllable fluorination of two-dimensional hexagonal boron nitride (h-BN). However, there is a lack of clear spectral interpretation, and seemingly conflicting measurements exist. To discern the structure−spectroscopy relation, we performed a comprehensive first-principles study on the boron 1s edge XPS of fluorinated h-BN (F-BN) nanosheets. By gradually introducing 1−6 fluorine atoms into different boron or nitrogen sites, we created various F-BN structures with doping ratios ranging from 1 to 6%. Our calculations reveal that fluorines landed at boron or nitrogen sites exert competitive effects on the B 1s binding energies (BEs), leading to red or blue shifts in different measurements. Our calculations affirmed the hypothesis that fluorination affects 1s BEs of all borons in the π-conjugated system, opposing the transferability from h-BN to F-BN. Additionally, we observe that BE generally increases with higher fluorine concentration when both borons and nitrogens are nonexclusively fluorinated. These findings provide critical insights into how fluorination affects boron's 1s BEs, contributing to a better understanding of fluorination functionalization processes in h-BN and its potential applications in materials science.

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Peculiar opportunities given by XPS spectroscopy for the clinician

Cited by 6 publications

References 153 publications

Self‐assembled silk fibroin cross‐linked with genipin supplements microbial carbonate precipitation in building material

Self‐assembled silk fibroin cross‐linked with genipin supplements microbial carbonate precipitation in building material

A QM/MM Study on the X-ray Spectra of Organic Proton Transfer Crystals of Isonicotinamides

Global Impact and Balancing Act: Deciphering the Effect of Fluorination on B 1s Binding Energies in Fluorinated h-BN Nanosheets

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