scholarly journals The Application of 29Si NMR Spectroscopy to the Analysis of Calcium Silicate-Based Cement using Biodentine™ as an Example

2019 ◽  
Vol 10 (2) ◽  
pp. 25 ◽  
Author(s):  
Qiu Li ◽  
Andrew P. Hurt ◽  
Nichola J. Coleman
Keyword(s):  
Calcium Silicate ◽  
Zirconium Oxide ◽  
Tricalcium Silicate ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
29Si Nmr ◽  
29Si Mas Nmr ◽  
Maximum Heat

Biodentine is one of the most successful and widely studied among the second generation of calcium silicate-based endodontic cements. Despite its popularity, the setting reactions of this cement system are not currently well understood. In particular, very little is known about the formation and structure of the major calcium silicate hydrate (C-S-H) gel phase, as it is difficult to obtain information on this poorly crystalline material by the traditional techniques of powder X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). In this study, the hydration reactions of Biodentine are monitored by XRD, FTIR, isothermal conduction calorimetry and, for the first time, 29Si magic angle spinning nuclear magnetic resonance spectroscopy (29Si MAS NMR) is used to investigate the structures of the anhydrous calcium silicate phases and the early C-S-H gel product. XRD analysis indicated that the anhydrous powder comprises 73.8 wt% triclinic tricalcium silicate, 4.45 wt% monoclinic β-dicalcium silicate, 16.6 wt% calcite and 5.15 wt% zirconium oxide. Calorimetry confirmed that the induction period for hydration is short, and that the setting reactions are rapid with a maximum heat evolution of 28.4 mW g−1 at 42 min. A progressive shift in the FTIR peak maximum from 905 to 995 cm−1 for the O-Si-O stretching vibrations accompanies the formation of the C-S-H gel during 1 week. The extent of hydration was determined by 29Si MAS NMR to be 87.0%, 88.8% and 93.7% at 6 h, 1 day and 1 week, respectively, which is significantly higher than that of MTA. The mean silicate chain length (MCL) of the C-S-H gel was also estimated by this technique to be 3.7 at 6 h and 1 day, and to have increased to 4.1 after 1 week. The rapid hydration kinetics of Biodentine, arising from the predominance of the tricalcium silicate phase, small particle size, and ‘filler effect’ of calcite and zirconium oxide, is a favorable characteristic of an endodontic cement, and the high values of MCL are thought to promote the durability of the cement matrix.

13C NMR investigation of CVD diamond: Correlation of NMR and Raman spectral linewidths

1994 ◽  
Vol 9 (3) ◽  
pp. 631-635 ◽  
Author(s):  
Lawrence H. Merwin ◽  
Curtis E. Johnson ◽  
Wayne A. Weimer
Keyword(s):  
Cvd Diamond ◽  
Optical Quality ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Defect Sites ◽  
Spin Resonance ◽  
Angle Spinning ◽  
Good Signal

Six CVD diamond thin films were examined by magic angle spinning (MAS) 13C nuclear magnetic resonance (NMR), Raman, and electron spin resonance spectroscopy. The use of film samples cut to the diameter of the magic-angle spinning rotor provided ease of spinning and the opportunity to obtain good signal-to-noise spectra in 4 to 16 h. MAS NMR linewidths exhibit a linear correlation with Raman linewidths and reflect the optical quality of the material. Residual MAS NMR linewidths most likely arise from a combination of crystal defect sites and paramagnetic effects.

scholarly journals Local Structures of Two-Dimensional Zeolites—Mordenite and ZSM-5—Probed by Multinuclear NMR

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4678 ◽  
Author(s):  
Marina G. Shelyapina ◽  
Rosario I. Yocupicio-Gaxiola ◽  
Iuliia V. Zhelezniak ◽  
Mikhail V. Chislov ◽  
Joel Antúnez-García ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Structural Changes ◽  
Resonance Method ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Nuclear Magnetic Resonance Method ◽  
29Si Mas Nmr ◽  
Zeolite Framework ◽  
One Pot

Mesostructured pillared zeolite materials in the form of lamellar phases with a crystal structure of mordenite (MOR) and ZSM-5 (MFI) were grown using CTAB as an agent that creates mesopores, in a one-pot synthesis; then into the CTAB layers separating the 2D zeolite plates were introduced by diffusion the TEOS molecules which were further hydrolyzed, and finally the material was annealed to remove the organic phase, leaving the 2D zeolite plates separated by pillars of silicon dioxide. To monitor the successive structural changes and the state of the atoms of the zeolite framework and organic compounds at all the steps of the synthesis of pillared MOR and MFI zeolites, the nuclear magnetic resonance method (NMR) with magic angle spinning (MAS) was applied. The 27Al and 29Si MAS NMR spectra confirm the regularity of the zeolite frameworks of the as synthetized materials. Analysis of the 1H and 13C MAS NMR spectra and an experiment with variable contact time evidence a strong interaction between the charged “heads” –[N(CH3)3]+ of CTAB and the zeolite framework at the place of [AlO4]− location. According to 27Al and 29Si MAS NMR the evacuation of organic cations leads to a partial but not critical collapse of the local zeolite structure.

scholarly journals Inorganic Polymers (Geopolymers) as Potential  Bioactive Materials

2021 ◽  
Author(s):  
◽  
Nils Rahner
Keyword(s):  
Calcium Phosphate ◽  
Calcium Hydroxide ◽  
Calcium Silicate ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
X Ray ◽  
Diametral Compression ◽  
Hydroxyl Apatite ◽  
Geopolymer Composites

<p>The primary aim of this project was to synthesise potassium activated geopolymer composites with bioactivity, and this was realised by adding 10wt% of calcium hydroxide, nano-structured calcium silicate or calcium phosphate to the geopolymer matrix. The synthesised samples were cured at 40'C then heated to 550'C and 600'C to reduce their alkalinity. Tensile strength was measured by diametral compression. The effect of exposure to simulated body fluid (SBF) was determined by x-ray diffractometry (XRD), 27Al, 29Si and 43Ca nuclear magnetic resonance spectroscopy with magic angle spinning (MAS NMR), pH measurements, inductively coupled plasma (ICP), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDS). XRD, 27Al and 29Si MAS NMR confirmed that all the samples retained their structural characteristics of a true aluminosilicate geopolymer, even after heating and exposure to SBF. EDS examination of the calcium-containing geopolymer composites showed that the calcium distribution was generally homogeneous. Exposure of the geopolymer composites to SBF at body temperature, was used to simulate the behaviour of the geopolymer composites in blood plasma. XRD and SEM/ EDS analysis showed that the geopolymers containing calcium hydroxide and calcium silicate formed hydroxyl apatite (HA) and carbonate hydroxyl apatite (HCA) after their exposure to SBF, indicating a degree of bioactivity. The absorption of calcium and phosphorus from the SBF and the observation of nano crystals rich in these elements provide some evidence of bioactive phases in the composite containing calcium phosphate and the reference geopolymer. The reference and the calcium phosphate geopolymer (both heated to 600XC) produced the lowest pH (ca.8) in the SBF. ICP analysis of the SBF after exposure shows that most of the aluminium remains in the geopolymer structure. The greatest release of aluminium (< 2.7 ppm after 168 hours) was found for the calcium hydroxide geopolymer (heated to 600'C). Diametral compression testing showed that the strength of the calcium phosphate-containing geopolymer heated to 550'C (4.17 MPa) is comparable with that of Bioglass(R)(5.56 MPa), currently used as a bio-material. Although none of the composites are ideal in all respects, they show sufficient promise to suggest that with further refinement, geopolymer materials may well be become candidates as bioactive ceramics.</p>

scholarly journals Inorganic Polymers (Geopolymers) as Potential  Bioactive Materials

2021 ◽  
Author(s):  
◽  
Nils Rahner
Keyword(s):  
Calcium Phosphate ◽  
Calcium Hydroxide ◽  
Calcium Silicate ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
X Ray ◽  
Diametral Compression ◽  
Hydroxyl Apatite ◽  
Geopolymer Composites

<p>The primary aim of this project was to synthesise potassium activated geopolymer composites with bioactivity, and this was realised by adding 10wt% of calcium hydroxide, nano-structured calcium silicate or calcium phosphate to the geopolymer matrix. The synthesised samples were cured at 40'C then heated to 550'C and 600'C to reduce their alkalinity. Tensile strength was measured by diametral compression. The effect of exposure to simulated body fluid (SBF) was determined by x-ray diffractometry (XRD), 27Al, 29Si and 43Ca nuclear magnetic resonance spectroscopy with magic angle spinning (MAS NMR), pH measurements, inductively coupled plasma (ICP), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDS). XRD, 27Al and 29Si MAS NMR confirmed that all the samples retained their structural characteristics of a true aluminosilicate geopolymer, even after heating and exposure to SBF. EDS examination of the calcium-containing geopolymer composites showed that the calcium distribution was generally homogeneous. Exposure of the geopolymer composites to SBF at body temperature, was used to simulate the behaviour of the geopolymer composites in blood plasma. XRD and SEM/ EDS analysis showed that the geopolymers containing calcium hydroxide and calcium silicate formed hydroxyl apatite (HA) and carbonate hydroxyl apatite (HCA) after their exposure to SBF, indicating a degree of bioactivity. The absorption of calcium and phosphorus from the SBF and the observation of nano crystals rich in these elements provide some evidence of bioactive phases in the composite containing calcium phosphate and the reference geopolymer. The reference and the calcium phosphate geopolymer (both heated to 600XC) produced the lowest pH (ca.8) in the SBF. ICP analysis of the SBF after exposure shows that most of the aluminium remains in the geopolymer structure. The greatest release of aluminium (< 2.7 ppm after 168 hours) was found for the calcium hydroxide geopolymer (heated to 600'C). Diametral compression testing showed that the strength of the calcium phosphate-containing geopolymer heated to 550'C (4.17 MPa) is comparable with that of Bioglass(R)(5.56 MPa), currently used as a bio-material. Although none of the composites are ideal in all respects, they show sufficient promise to suggest that with further refinement, geopolymer materials may well be become candidates as bioactive ceramics.</p>

scholarly journals The omics era: what can nuclear magnetic resonance tell us on metabolomics?

2018 ◽  
Vol 32 (4) ◽  
Author(s):  
Franca Castiglione ◽  
Monica Ferro ◽  
Andrea Mele
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Biological Process ◽  
Ex Vivo ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Metabolic Fingerprint ◽  
Nuclear Magnetic

A brief overview of the potentiality and use of the metabolic fingerprint of a system or biological process is here proposed. The information on the type, quantity and variation of the pool of metabolites and its relationship with a given biological process is commonly referred to as metabolomics. One powerful analytical approach to the detection and quantitation of metabolites is by Nuclear Magnetic Resonance Spectroscopy (NMR). Additionally, the recently introduced High Resolution Magic Angle Spinning (HR-MAS) NMR approach improved dramatically the potentiality of the method allowing direct sampling of ex vivo specimens, such as tissues and cells, without any pre-treatment or extraction steps. The NMR data can be processed towards the target or non-target analysis of the metabolites. The former passes through the identification of all the metabolites, the latter adopts a multivariate statistical approach such as Principal Components Analysis. In this article, the main methodological points of NMR analysis with multivariate statistics are briefly outlined and discussed. A final case-study on the discrimination of healthy and neoplastic tissues via HR-MAS NMR metabolomics is reported as a paradigmatic application.

The Spectroscopy Characterization of Kaolinite-Organic Intercalation Materials

2007 ◽  
Vol 353-358 ◽  
pp. 1362-1365 ◽  
Author(s):  
Lin Jiang Wang ◽  
Xiang Li Xie ◽  
Da Qing Wu
Keyword(s):  
Chemical Shifts ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
1H Mas Nmr ◽  
Surface Hydroxyl ◽  
Inner Surface ◽  
Ft Ir ◽  
Intercalation Materials

Kaolinite/formamide intercalation materials are characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy(FT-IR), Raman spectroscopy and 1H magic angle spinning nuclear magnetic resonance spectroscopy (1H MAS NMR). The d(001) spacing of kaolinite treated with formamide is 1.020nm, which is larger than that of the original clay. The 1H MAS NMR graphs show that the proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinte are δ-1.3 and δ2.4 respectively. After formamide intercalation, the proton peaks of the inner surface hydroxyls shifted to high-field with δ2.3, the proton peak of the inner hydroxyl shifted to δ-0.3 toward low-field. In the hydroxyl stretching vibration region of Raman spectrum, the formamide intercalation resulted in the decrease of the intensities of kaolinite inner surface hydroxyl bands at 3699cm-1,3682cm-1, 3665cm-1 and 3642cm-1, and the appearance of additional bands at 3610cm-1,3628cm-1. In the NH stretching region of FT-IR spectrum, two bands are observed at 3336cm-1 and 3466cm-1 corresponding to the two types of the hydrogen bonds between formamide and kaolinite. In the carboxyl stretching region, an additional band at 1667cm-1 is assigned to C=O group that bonded to the inner surface hydroxyl of kaolinite.

scholarly journals MBRS-69. METABOLITE PROFILING OF SHH MEDULLOBLASTOMA IDENTIFIES A SUBSET OF CHILDHOOD TUMOURS ENRICHED FOR HIGH-RISK MOLECULAR BIOMARKERS AND CLINICAL FEATURES

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii410-iii410
Author(s):  
Christopher Bennett ◽  
Sarah Kohe ◽  
Florence Burte ◽  
Heather Rose ◽  
Debbie Hicks ◽  
...  
Keyword(s):  
High Risk ◽  
Metabolite Profiling ◽  
Unmet Need ◽  
Magic Angle Spinning ◽  
Molecular Biomarkers ◽  
Mycn Amplification ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Metabolite Profiles ◽  
Cluster 2

Abstract SHH medulloblastoma patients have a variable prognosis. Infants (&lt;3–5 years at diagnosis) are associated with a good prognosis, while disease-course in childhood is associated with specific prognostic biomarkers (MYCN amplification, TP53 mutation, LCA histology; all high-risk). There is an unmet need to identify prognostic subgroups of SHH tumours rapidly in the clinical setting, to aid in real-time risk stratification and disease management. Metabolite profiling is a powerful technique for characterising tumours. High resolution magic angle spinning NMR spectroscopy (HR-MAS) can be performed on frozen tissue samples and provides high quality metabolite information. We therefore assessed whether metabolite profiles could identify subsets of SHH tumours with prognostic potential. Metabolite concentrations of 22 SHH tumours were acquired by HR-MAS and analysed using unsupervised hierarchical clustering. Methylation profiling assigned the infant and childhood SHH subtypes, and clinical and molecular features were compared between clusters. Two clusters were observed. A significantly higher concentration of lipids was observed in Cluster 1 (t-test, p=0.012). Cluster 1 consisted entirely of childhood-SHH whilst Cluster 2 included both childhood-SHH and infant-SHH subtypes. Cluster 1 was enriched for high-risk markers - LCA histology (3/7 v. 0/5), MYCN amplification (2/7 v. 0/5), TP53 mutations (3/7 v. 1/5) and metastatic disease - whilst having a lower proportion of TERT mutations (0/7 v. 2/5) than Cluster 2. These pilot results suggest that (i) it is possible to identify childhood-SHH patients linked to high-risk clinical and molecular biomarkers using metabolite profiles and (ii) these may be detected non-invasively in vivo using magnetic-resonance spectroscopy.

scholarly journals Physicochemical properties and structural dynamics of organic–inorganic hybrid [NH3(CH2)3NH3]ZnX4 (X = Cl and Br) crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ae Ran Lim ◽  
Sun Ha Kim ◽  
Yong Lak Joo
Keyword(s):  
Structural Dynamics ◽  
Chemical Shifts ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Scanning Calorimetry ◽  
Inorganic Hybrid ◽  
Halogen Atoms

AbstractThe physical properties of the organic–inorganic hybrid crystals having the formula [NH3(CH2)3NH3]ZnX4 (X = Cl, Br) were investigated. The phase transition temperatures (TC; 268K for Cl and 272K for Br) of the two crystals bearing different halogen atoms in their skeletons were determined through differential scanning calorimetry. The thermodynamic properties of the two crystals were investigated through thermogravimetric analysis. The structural dynamics, particularly the role of the [NH3(CH2)3NH3] cation, were probed through 1H and 13C magic-angle spinning nuclear magnetic resonance spectroscopy as a function of temperature. The 1H and 13C NMR chemical shifts did not show any changes near TC. In addition, the 1H spin–lattice relaxation time (T1ρ) varied with temperature, whereas the 13C T1ρ values remained nearly constant at different temperatures. The T1ρ values of the atoms in [NH3(CH2)3NH3]ZnCl4 were higher than those in [NH3(CH2)3NH3]ZnBr4. The observed differences in the structural dynamics obtained from the chemical shifts and T1ρ values of the two compounds can be attributed to the differences in the bond lengths and halogen atoms. These findings can provide important insights or potential applications of these crystals.

scholarly journals Preparation of Li3PS4–Li3PO4 Solid Electrolytes by Liquid-Phase Shaking for All-Solid-State Batteries

2021 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
Nguyen H. H. Phuc ◽  
Takaki Maeda ◽  
Tokoharu Yamamoto ◽  
Hiroyuki Muto ◽  
Atsunori Matsuda
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Liquid Phase ◽  
Room Temperature ◽  
Reaction Medium ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Synthesis Methods ◽  
Magic Angle ◽  
Angle Spinning

A solid solution of a 100Li3PS4·xLi3PO4 solid electrolyte was easily prepared by liquid-phase synthesis. Instead of the conventional solid-state synthesis methods, ethyl propionate was used as the reaction medium. The initial stage of the reaction among Li2S, P2S5 and Li3PO4 was proved by ultraviolet-visible spectroscopy. The powder X-ray diffraction (XRD) results showed that the solid solution was formed up to x = 6. At x = 20, XRD peaks of Li3PO4 were detected in the prepared sample after heat treatment at 170 °C. However, the samples obtained at room temperature showed no evidence of Li3PO4 remaining for x = 20. Solid phosphorus-31 magic angle spinning nuclear magnetic resonance spectroscopy results proved the formation of a POS33− unit in the sample with x = 6. Improvements of ionic conductivity at room temperature and activation energy were obtained with the formation of the solid solution. The sample with x = 6 exhibited a better stability against Li metal than that with x = 0. The all-solid-state half-cell employing the sample with x = 6 at the positive electrode exhibited a better charge–discharge capacity than that employing the sample with x = 0.

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