| 1. |
- Beţiu, Alina Maria, et al.
(author)
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Dose-dependent effects of acetaminophen and ibuprofen on mitochondrial respiration of human platelets
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In: Molecular and Cellular Biochemistry. - 0300-8177.
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Journal article (peer-reviewed)abstract
- Acetaminophen and ibuprofen are widely used over-the-counter medications to reduce fever, pain, and inflammation. Although both drugs are safe in therapeutic concentrations, self-medication is practiced by millions of aged patients with comorbidities that decrease drug metabolism and/or excretion, thus raising the risk of overdosage. Mitochondrial dysfunction has emerged as an important pathomechanism underlying the organ toxicity of both drugs. Assessment of mitochondrial oxygen consumption in peripheral blood cells is a novel research field Cu several applications, including characterization of drug toxicity. The present study, conducted in human platelets isolated from blood donor-derived buffy coat, was aimed at assessing the acute, concentration-dependent effects of each drug on mitochondrial respiration. Using the high-resolution respirometry technique, a concentration-dependent decrease of oxygen consumption in both intact and permeabilized platelets was found for either drug, mainly by inhibiting complex I-supported active respiration. Moreover, ibuprofen significantly decreased the maximal capacity of the electron transport system already from the lowest concentration. In conclusion, platelets from healthy donors represents a population of cells easily available, which can be routinely used in studies assessing mitochondrial drug toxicity. Whether these results can be recapitulated in patients treated with these medications is worth further investigation as potential peripheral biomarker of drug overdose.
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| 2. |
- Bețiu, Alina M., et al.
(author)
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Cell‐permeable succinate rescues mitochondrial respiration in cellular models of amiodarone toxicity
- 2021
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:21
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Journal article (peer-reviewed)abstract
- Amiodarone is a potent antiarrhythmic drug and displays substantial liver toxicity in hu-mans. It has previously been demonstrated that amiodarone and its metabolite (desethylamioda-rone, DEA) can inhibit mitochondrial function, particularly complexes I (CI) and II (CII) of the elec-tron transport system in various animal tissues and cell types. The present study, performed in human peripheral blood cells, and one liver‐derived human cell line, is primarily aimed at assessing the concentration‐dependent effects of these drugs on mitochondrial function (respiration and cellular ATP levels). Furthermore, we explore the efficacy of a novel cell‐permeable succinate prodrug in alleviating the drug‐induced acute mitochondrial dysfunction. Amiodarone and DEA elicit a con-centration‐dependent impairment of mitochondrial respiration in both intact and permeabilized platelets via the inhibition of both CI‐ and CII‐supported respiration. The inhibitory effect seen in human platelets is also confirmed in mononuclear cells (PBMCs) and HepG2 cells. Additionally, amiodarone elicits a severe concentration‐dependent ATP depletion in PBMCs, which cannot be explained solely by mitochondrial inhibition. The succinate prodrug NV118 alleviates the respiratory deficit in platelets and HepG2 cells acutely exposed to amiodarone. In conclusion, amiodarone severely inhibits metabolism in primary human mitochondria, which can be counteracted by in-creasing mitochondrial function using intracellular delivery of succinate.
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| 3. |
- Hagara, Jakub, et al.
(author)
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Novel highly substituted thiophene-based n-type organic semiconductor : structural study, optical anisotropy and molecular control
- 2020
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In: CrystEngComm. - : Royal Society of Chemistry. - 1466-8033. ; 22:42, s. 7095-7103
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Journal article (peer-reviewed)abstract
- Oligothiophenes and their functionalized derivatives have been shown to be a viable option for high-performance organic electronic devices. The functionalization of oligothiophene-based materials allows further tailoring of their properties for specific applications. We have synthesized a new thiophene-based molecule 1-[5'-(2-naphthyl)-2,2'-bithiophen-5-yl]hexan-1-one (NCOH), and we have studied the optical and structural properties of NCOH thin films. NCOH is a highly substituted member of the oligothiophene family, designed to improve its molecular stacking, where the presence of an electron-withdrawing group enhances its electron transport capabilities. Employing in situ and time-resolved grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements, we determined the NCOH thin film crystallographic structure and its evolution starting from the early stages of the film growth. We observed strong optical anisotropy resulting from a highly oriented crystallographic structure. Additionally, we investigated the substrate-induced changes of the molecular orientation utilizing the few-layer MoS2 with different orientations of the atomic layers. This study, with its primary focus on the fundamentally important n-type molecular semiconductor, contributes to the field of organic-based (opto-)electronics.
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| 4. |
- Jensen, Thomas N., et al.
(author)
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Correlation between stoichiometry and surface structure of the polar MgAl2O4(100) surface as a function of annealing temperature
- 2015
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In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 17:8, s. 5795-5804
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Journal article (peer-reviewed)abstract
- The correlation between surface structure, stoichiometry and atomic occupancy of the polar MgAl2O4(100) surface has been studied with an interplay of noncontact atomic force microscopy, X-ray photoelectron spectroscopy and surface X-ray diffraction under ultrahigh vacuum conditions. The Al/Mg ratio is found to significantly increase as the surface is sputtered and annealed in oxygen at intermediate temperatures ranging from 1073-1273 K. The Al excess is explained by the observed surface structure, where the formation of nanometer-sized pits and elongated patches with Al terminated step edges contribute to stabilizing the structure by compensating surface polarity. Surface X-ray diffraction reveals a reduced occupancy in the top two surface layers for both Mg, Al, and O and, moreover, vacancies are preferably located in octahedral sites, indicating that Al and Mg ions interchange sites. The excess of Al and high concentration of octahedral vacancies, very interestingly, indicates that the top few surface layers of the MgAl2O4(100) adopts a surface structure similar to that of a spinel-like transition Al2O3 film. However, after annealing at a high temperature of 1473 K, the Al/Mg ratio restores to its initial value, the occupancy of all elements increases, and the surface transforms into a well-defined structure with large flat terraces and straight step edges, indicating a restoration of the surface stoichiometry. It is proposed that the tetrahedral vacancies at these high temperatures are filled by Mg from the bulk, due to the increased mobility at high annealing temperatures.
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| 5. |
- Rasmussen, Morten K., et al.
(author)
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Stable Cation Inversion at the MgAl2O4(100) Surface
- 2011
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In: Physical Review Letters. - 1079-7114. ; 107:3
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Journal article (peer-reviewed)abstract
- From an interplay of atom-resolved noncontact atomic force microscopy, surface x-ray diffraction experiments, and density functional theory calculations, we reveal the detailed atomic-scale structure of the (100) surface of an insulating ternary metal oxide, MgAl2O4 (spinel). We surprisingly find that the MgAl2O4(100) surface is terminated by an Al and O-rich structure with a thermodynamically favored amount of Al atoms interchanged with Mg. This finding implies that so-called Mg-Al antisites, which are defects in the bulk of MgAl2O4, become a thermodynamically stable and integral part of the surface.
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| 6. |
- Resta, Andrea, et al.
(author)
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Ammonia Oxidation over a Pt25Rh75(001) Model Catalyst Surface : An Operando Study
- 2020
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:40, s. 22192-22199
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Journal article (peer-reviewed)abstract
- The ammonia oxidation reaction over a PtRh binary alloy has been studied with a surface science approach by operando techniques such as near-ambient pressure X-ray photoemission spectroscopy (NAP-XPS) and surface X-ray diffraction (SXRD) combined with mass spectrometry. The article will explore the surface evolution across five different oxygen to ammonia ratios in the millibar regime for two different temperatures. The presented data set allows us to link variations in the atomic structures measured by diffraction methods and surface species information from NAP-XPS to reaction products in the gas phase. We will show that NO production coincides with significant changes of the surface structure and the formation of a RhO2 surface oxide. It was also observed that the RhO2 surface oxide only fully forms when the nitrogen signal in the N1s has disappeared.
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| 7. |
- Samikannu, Ajaikumar, et al.
(author)
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The activation of C–O bonds in lignin Miscanthus over acidic heterogeneous catalysts: towards lignin depolymerisation to monomer units
- 2024
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In: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 14:8, s. 9723-9737
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Journal article (peer-reviewed)abstract
- One-pot depolymerisation of lignin, extracted from Miscanthus plants under acidic (formic acid lignin, FAL) or basic (ammonia lignin, AL) conditions, over Ni- and/or Nb-doped SBA-15, was the subject of this study. The aforementioned acid catalysts prepared by sol–gel method were characterized by SEM–EDX, ATR-FTIR, Raman, XRD, N2 adsorption/desorption isotherms, CO2-TPD and NH3-TPD techniques. The increase in acidity due to the insertion of Nb into the SBA-15 structure promoted the selective cleavage of β–O–4 from ammonia lignin, leading to aromatic monomer yields up to 22 wt% in 6 h at 180 °C under 50 atm H2. The catalytic performances of Ni-Nb-SBA-15 as well as its stability were influenced by the chemical composition of the lignin sample as results of its extraction from the Miscanthus plant.
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| 8. |
- Vlad, Alina, et al.
(author)
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Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation
- 2012
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 86:3
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Journal article (peer-reviewed)abstract
- We investigated the interaction of oxygen with the Pd(112) surface from ultrahigh vacuum up to 5 mbars oxygen partial pressure in a temperature range from 523 to 673 K. We combined in situ surface x-ray diffraction with scanning tunneling microscopy, high-resolution core-level spectroscopy, and low-energy electron diffraction. A structural model of the clean Pd(112) is proposed based on the x-ray-diffraction data. The morphology of the Pd(112) surface is strongly influenced by the oxidation conditions: at 673 K, upon exposure to oxygen at pressures from 2 x 10(-8) to 5 x 10(-5) mbar, the (112) surface undergoes a massive rearrangement and (113)and (335)-type facets are formed. Further increase of the O-2 partial pressure leads to a new rearrangement into (111)- and (113)-type facets. This is in contrast to the previous observation that (112) facets are stabilized on MgO supported Pd nanoparticles under oxygen exposure [P. Nolte, A. Stierle, N. Kasper, N. Y. Jin-Phillipp, N. Jeutter, and H. Dosch, Nano Lett. 11, 4697 (2011)]. Based on the core-level spectroscopy and scanning tunneling microscopy measurements, the transition from chemisorbed oxygen to surface oxide formation was identified to take place at pressures of 10(-3) mbar O-2 and 623 K. Kinetic barriers for the formation of the PdO bulk oxide are observed to be reduced compared to low index Pd surfaces.
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