| 1. |
- Figueira, João, et al.
(författare)
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Metabolite quantification by NMR and LC-MS/MS reveals differences between unstimulated, stimulated, and pure parotid saliva
- 2017
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Ingår i: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier. - 0731-7085 .- 1873-264X. ; 140, s. 295-300
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Tidskriftsartikel (refereegranskat)abstract
- Saliva is a readily available biofluid that is sensitive to metabolic changes and can be collected through rapid and non-invasive collection procedures, and it shows great promise for clinical metabolomic studies. This work studied the metabolite composition of, and the differences between, saliva samples collected by unstimulated spitting/drooling, paraffin chewing-stimulated spitting, and parotid gland suction using targeted nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for metabolite quantification. As applied here, these two analytical techniques provide complementary metabolite information and together extend the metabolome coverage with robust NMR quantification of soluble metabolites and sensitive targeted LC-MS/MS analysis of bioactive lipids in specific metabolic pathways. The NMR analysis was performed on ultrafiltrated (3kDa cutoff) saliva samples and resulted in a total of 45 quantified metabolites. The LC-MS/MS analysis was performed on both filtered and unfiltered samples and resulted in the quantification of two endocannabinoids (AEA and PEA) and 22 oxylipins, which at present is the most comprehensive targeted analysis of bioactive lipids in human saliva. Important differences in the metabolite composition were observed between the three saliva sample collection methods, which should be taken into consideration when designing metabolomic studies of saliva. Furthermore, the combined use of the two metabolomics platforms (NMR and LC-MS/MS) proved to be viable for research and clinical studies of the salivary metabolome.
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| 2. |
- Gouveia, Marisol, et al.
(författare)
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Poly(alkylidenimine) Dendrimers Functionalized with the Organometallic Moiety [Ru(η5-C5H5)(PPh3)2]+ as Promising Drugs Against Cisplatin-Resistant Cancer Cells and Human Mesenchymal Stem Cells
- 2018
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 23:6
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Tidskriftsartikel (refereegranskat)abstract
- Here and for the first time, we show that the organometallic compound [Ru(η5-C5H5)(PPh3)2Cl] (RuCp) has potential to be used as a metallodrug in anticancer therapy, and further present a new approach for the cellular delivery of the[Ru(η5-C5H5)(PPh3)2]+ fragment via coordination on the periphery of low-generation poly(alkylidenimine) dendrimers through nitrile terminal groups. Importantly, both the RuCp and the dendrimers functionalized with [Ru(η5-C5H5)(PPh3)2]+ fragments present remarkable toxicity towards a wide set of cancer cells (Caco-2, MCF-7, CAL-72, and A2780 cells), including cisplatin-resistant human ovarian carcinoma cell lines (A2780cisR cells). Also, RuCp and the prepared metallodendrimers are active against human mesenchymal stem cells (hMSCs), which are often found in the tumor microenvironment where they seem to play a role in tumor progression and drug resistance.
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| 3. |
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| 4. |
- Baba Ahmadi, Arezou, 1985, et al.
(författare)
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Chloride binding in Portland composite cements containing metakaolin and silica fume
- 2022
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Ingår i: Cement and Concrete Research. - : Elsevier BV. - 0008-8846 .- 1873-3948. ; 161
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates how the composition of Portland composite cements affects their chloride-binding properties. Hydrated cement pastes prepared with a reference Portland cement and composite Portland cements containing metakaolin and/or silica fume were exposed to NaCl or CaCl2 solutions. Chloride-binding isotherms were determined and the hydrate assemblage was investigated using TGA, XRD, 27Al NMR, 29Si NMR and thermodynamic modelling. Compared to the reference Portland cement paste, silica fume replacement did not alter the chloride-binding capacity. The metakaolin replacement resulted in the highest chloride-binding capacity. When combining silica fume with metakaolin, the chloride binding is similar to the reference Portland cement. In this study the differences in chloride binding were linked not only to changes in the AFm content, but also to alterations in the Al-uptake and chain length of the C(-A)-S-H.
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| 5. |
- Babaahmadi, Arezou, et al.
(författare)
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Chloride binding in slag containing composite cements
- 2023. - 1
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Ingår i: International RILEM conference on synergising expertise towards sustainability and robustness of cement-based materials and concrete structures. - Cham : Springer. - 9783031332104 - 9783031332135 - 9783031332111 ; , s. 645-657, s. 645-657
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Bokkapitel (refereegranskat)abstract
- Higher availability of grand granulated blast furnace slag compared to coal fly ash has attributed lots of attention to this supplementary cementitious material in recent years, especially with respect to applications in infrastructure. Therefore, further research on long term performance of slag containing binders in chloride containing environments is promoted. In this article chloride binding in a high slag containing composite binder (70% substitution) with respect to the changes in structure of CSH gel prior and after exposure to chlorides and its effect on chemical and physical chloride binding is accounted for. The changes in the structure of CSH are accounted by NMR analysis and the effect of these changes on chloride binding is addressed through adsorption tests. The results are compared with a ternary binder of cement-silica fume-metakaolin, given the relatively similar chemical composition between these two composite binders, as well as a reference Portland cement binder. The results infer that the slag containing binder exhibits higher chloride binding capacity compared to the metakaolin-silica fume containing. Moreover, a higher share of chemically bound chloride (meaning a lower physical binding) in SCM containing binders is foreseen compared to pure Portland cement system, due to the increased C(-A)-S-H chain length and Al/Si molar ratio in these binders. Furthermore, it is shown that exposure to NaCl causes a higher share of chemically bound chlorides compared to the CaCl2 exposure while the total bound chloride content increases upon exposure to CaCl2.
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| 6. |
- Borne, Kurtis D., et al.
(författare)
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Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane
- 2024
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Ingår i: NATURE CHEMISTRY. - 1755-4330 .- 1755-4349. ; 16, s. 499-505
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Tidskriftsartikel (refereegranskat)abstract
- The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. Here we study the electronic relaxation of quadricyclane after exciting in the ultraviolet (201 nanometres) using time-resolved gas-phase extreme ultraviolet photoelectron spectroscopy combined with non-adiabatic molecular dynamics simulations. We identify two competing pathways by which electronically excited quadricyclane molecules relax to the electronic ground state. The fast pathway (<100 femtoseconds) is distinguished by effective coupling to valence electronic states, while the slow pathway involves initial motions across Rydberg states and takes several hundred femtoseconds. Both pathways facilitate interconversion between the two isomers, albeit on different timescales, and we predict that the branching ratio of norbornadiene/quadricyclane products immediately after returning to the electronic ground state is approximately 3:2.
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| 7. |
- Bratthäll, Tove, et al.
(författare)
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Influence of divalent cations on the extraction of organic acids in coffee determined by GC-MS and NMR
- 2024
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- The perceived flavor of coffee varies depending on the composition of the brewing water, and the influencing mechanisms are poorly understood. To investigate the effect of dissolved divalent cations on the extraction of organic acids in coffee, magnesium and calcium chloride salts were added pre- and post-brew. Citric, malic, lactic and quinic acid were analyzed using gas chromatography – mass spectrometry and nuclear magnetic resonance techniques. At concentrations typically found in drinking water, the salts resulted in limited variation of the acid content, while ten-fold higher salt concentrations produced more pronounced variations. Comparisons between pre- and post-brew additions showed similar acid content in most cases, suggesting that extraction of acids proceeds independent of the water composition. Interactions taking place post-brew may, however, influence the perceived flavor. A scientific basis for water quality recommendations in the coffee industry is long overdue and this work provides experimental and analytical contributions to continued research.
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| 8. |
- Figueira, Joao, et al.
(författare)
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NMR analysis of the human saliva metabolome distinguishes dementia patients from matched controls
- 2016
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Ingår i: Molecular Biosystems. - : Royal Society of Chemistry (RSC). - 1742-206X .- 1742-2051. ; 12:8, s. 2562-2571
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Tidskriftsartikel (refereegranskat)abstract
- Saliva is a biofluid that is sensitive to metabolic changes and is straightforward to collect in a non-invasive manner, but it is seldom used for metabolite analysis when studying neurodegenerative disorders. We present a procedure for both an untargeted and targeted analysis of the saliva metabolome in which nuclear magnetic resonance (NMR) spectroscopy is used in combination with multivariate data analysis. The applicability of this approach is demonstrated on saliva samples selected from the 25 year prospective Betula study, including samples from dementia subjects with either Alzheimer's disease (AD) or vascular dementia at the time of sampling or who developed it by the next sampling/assessment occasion five years later, and age-, gender-, and education-matched control individuals without dementia. Statistically significant multivariate models were obtained that separated patients with dementia from controls and revealed seven discriminatory metabolites. Dementia patients showed significantly increased concentrations of acetic acid (fold change (fc) = 1.25, p = 2 x 10(-5)), histamine (fc = 1.26, p = 0.019), and propionate (fc = 1.35, p = 0.002), while significantly decreased levels were observed for dimethyl sulfone (fc = 0.81, p = 0.005), glycerol (fc = 0.79, p = 0.04), taurine (fc = 0.70, p = 0.007), and succinate (fc = 0.62, p = 0.008). Histamine, succinate, and taurine are known to be important in AD, and acetic acid and glycerol are involved in related pathways. Dimethyl sulfone and propionate originate from the diet and bacterial flora and might reflect poorer periodontal status in the dementia patients. For these seven metabolites, a weak but statistically significant pre-diagnostic value was observed. Taken together, we present a robust and general NMR analysis approach for studying the saliva metabolome that has potential use for screening and early detection of dementia.
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| 9. |
- Figueira, Joao, et al.
(författare)
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Serum Metabolite Markers of Dementia Through Quantitative NMR Analysis : The Importance of Threonine-Linked Metabolic Pathways
- 2019
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 69:3, s. 763-774
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Tidskriftsartikel (refereegranskat)abstract
- There is a great need for diagnostic biomarkers of impending dementia. Metabolite markers in blood have been investigated in several studies, but inconclusive findings encourage further investigation, particularly in the pre-diagnostic phase. In the present study, the serum metabolomes of 110 dementia or pre-diagnostic dementia individuals and 201 healthy individuals matched for age, gender, and education were analyzed by nuclear magnetic resonance spectroscopy in combination with multivariate data analysis. 58 metabolites were quantified in each of the 311 samples. Individuals with dementia were discriminated from controls using a panel of seven metabolites, while the pre-diagnostic dementia subjects were distinguished from controls using a separate set of seven metabolites, where threonine was a common significant metabolite in both panels. Metabolite and pathway alterations specific for dementia and pre-diagnostic dementia were identified, in particular a disturbed threonine catabolism at the pre-diagnostic stage that extends to several threonine-linked pathways at the dementia stage.
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| 10. |
- Latham, Kenneth G., et al.
(författare)
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Examination of how variations in lignin properties from Kraft and organosolv extraction influence the physicochemical characteristics of hydrothermal carbon
- 2021
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier. - 0165-2370 .- 1873-250X. ; 155
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Tidskriftsartikel (refereegranskat)abstract
- Seven different lignin samples, three from Kraft extraction and four from organosolv extraction, were subjected to hydrothermal treatment at 260℃ for four hours to assess the impact of lignin type on the physicochemical properties of the hydrothermal material. The 13C Solid state NMR, XPS, FTIR and SEM analysis revealed that the different sources of lignin and the extraction conditions created variations in the degree of syringyl and guaiacyl subunits, inter-unit bonding arrangements, morphology and surface composition. Hydrothermal carbonization appeared to “normalize” the differences between each of the lignin samples, via breaking β-O-4 or α-O-4 linkages, removal of methoxy and syringyl subunits, and creation of C C and 4-O-5 linkages to polymerization into large 100−200 μm amorphous carbon particles. Overall, this study indicates that the source and extraction type have minimal influence on the physicochemical structure and morphology of the final hydrothermal product.
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