| 1. |
- Amft, Martin, et al.
(författare)
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A Molecular Mechanism for the Water-Hydroxyl Balance during Wetting of TiO2
- 2013
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:33, s. 17078-17083
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Tidskriftsartikel (refereegranskat)abstract
- We show that the formation of the wetting layer and the experimentally observed continuous shift of the H2O-OH balance toward molecular water at increasing coverage on a TiO2(110) surface can be rationalized on a molecular level. The mechanism is based on the initial formation of stable hydroxyl pairs, a repulsive interaction between these pairs, and an attractive interaction with respect to water molecules. The experimental data are obtained by synchrotron radiation photoelectron spectroscopy and interpreted with the aid of density functional theory calculations and Monte Carlo simulations.
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| 2. |
- Blomberg, Sara, et al.
(författare)
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Generation and oxidation of aerosol deposited PdAg nanoparticles
- 2013
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 616, s. 186-191
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Tidskriftsartikel (refereegranskat)abstract
- PdAg nanoparticles with a diameter of 10 nm have been generated by an aerosol particle method, and supported on a silica substrate. By using a combination of X-ray Energy Dispersive Spectroscopy and X-ray Photoelectron Spectroscopy it is shown that the size distribution of the particles is narrow and that the two metals form an alloy with a mixture of 75% Pd and 25% Ag. Under oxidizing conditions, Pd is found to segregate to the surface and a thin PdO like oxide is formed similar to the surface oxide previously reported on extended PdAg and pure Pd surfaces. (C) 2013 Elsevier B.V. All rights reserved.
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| 3. |
- Blomberg, Sara, et al.
(författare)
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In Situ X-Ray Photoelectron Spectroscopy of Model Catalysts: At the Edge of the Gap
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 110:11
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Tidskriftsartikel (refereegranskat)abstract
- We present high-pressure x-ray photoelectron spectroscopy (HP-XPS) and first-principles kinetic Monte Carlo study addressing the nature of the active surface in CO oxidation over Pd(100). Simultaneously measuring the chemical composition at the surface and in the near-surface gas phase, we reveal both O-covered pristine Pd(100) and a surface oxide as stable, highly active phases in the near-ambient regime accessible to HP-XPS. Surprisingly, no adsorbed CO can be detected during high CO2 production rates, which can be explained by a combination of a remarkably short residence time of the CO molecule on the surface and mass-transfer limitations in the present setup. DOI: 10.1103/PhysRevLett.110.117601
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| 4. |
- Borg, Natalia
(författare)
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Distribution of antiviral nucleoside analogues into brain and skin
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to study physiological and physico-chemical factors influencing the pharmacokinetics and distribution over the blood-brain barrier of antiviral nucleoside analogues in the rat, and to study the distribution to the human skin in vivo of an anti-herpetic nucleoside analogue. Microdialysis was used to sample the free (unbound) extracellular concentration of the nucleoside analogues from the brain tissue, muscle and blood in the rat and from the dermis of healthy human volunteers. Microdialysis was also used in vitro to determine the plasma protein binding of the nucleoside analogues. HPLC was used for analysis and quantification of the nucleoside analogues. The HPLC assays were optimised by using PLS (Partial Least Square analysis), which allows a rapid development of assays for new nucleoside analogues. The effect of varying perfusion medium osmolality on the in vivo microdialysis recovery of caffeine and 5-chloro-2', 3'-dideoxy-3'-fluorouridine was investigated in rat brain. A linear correlation between the recovery over microdialysis membrane and osmolality of perfusion medium was demonstrated for both substances within a certain interval. At higher osmolality (>627 mosmol/l) of the perfusion medium the increase of the recovery of caffeine was non-linear, indicating that there is an upper limit of the change in extracellular volume in the brain. The distribution of alovudine (3'-fluorothymidine) to the brain and to the cerebrospinal fluid was studied after i. v. infusion and after s.c. injection. The concentration gradient between brain extracellular fluid and cerebrospinal fluid indicates that there is an active efflux of alovudine from the brain. Acetazolamide, a carbonic anhydrase inhibitor, inhibiting the cerebrospinal fluid production in the choroid plexus, had no influence on the AUC (Area Under the plasma concentration-time Curve) ratio brain/blood. This suggests that alovudine transport to the brain does not occur via the cerebrospinal fluid, but via cerebrovascular endothelium. Thymidine, administered locally or systemically, had no influence on the AUC ratio brain/blood, indicating that thymidine transport is not involved. Two inhibitors of transport proteins, probenecid and quinidine, were also used to study the alovudine transport system. Quinidine, but not probenecid, significantly decreased the alovudine concentration in the brain and increased the concentration gradient. Both perfusion through the microdialysis probe with alovudine solution at increasing concentration and quirridine administration significantly increased the microdialysis recovery of alovudine. The distribution into the rat brain of 5-substituted alovudine analogues and physico-chemical properties of these substances was studied and a multivariate quantitative structure-kinetic relationship was calculated. No correlation between the transport over the blood-brain barrier and the lipophilicity (octanol/water partition coefficient) could be demonstrated. Instead the pKa and the electronic distribution properties of the 5-substituent were found to influence the concentration gradient across the blood-brain barrier. This result indicates that alovudine analogues are subject to active transport (carrier-mediated) rather than passive diffusion across the blood-brain barrier. The distribution to the brain of the cytidine analogues: 2', 3'-dideoxycytidine and 3'-hydroxymethyl-2', 3'- dideoxycytidine over the blood-brain barrier were studied after s.c. administration. The pharmacokinetic properties were found to be similar. There was no significant difference with respect to blood-brain barrier transport between 2', 3'-dideoxycytidine and 3'-hydroxymethyl-2', 3'-dideoxycytidine. Thus, the sugar structure did not influence their transport into the brain. The distribution to the brain of penciclovir after i.v. injection or p.o. administration of its prodrug famciclovir and during i.v. infusion of penciclovir or famciclovir was studied in rats. Penciclovir was found to cross the blood-brain barrier and achieved significant concentrations in the brain. The distribution of penciclovir into the dermis of healthy volunteers was studied after a single dose of its prodrug, famciclovir, by microdialysis and by the suction blister technique. The results obtained with the suction blister technique and by microdialysis were similar and both showed that pencilovir reaches the skin in concentrations expected to inhibit herpes virus replication. However, microdialysis allows continuous sampling of the drug over a prolonged time after administration. The microdialysis concentration was decreased by cold and by adrenaline- mediated vasoconstriction.
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| 5. |
- Danielsson, Bengt, et al.
(författare)
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Antidepressants and antipsychotics classified with torsades de pointes arrhythmia risk and mortality in older adults - a Swedish nationwide study
- 2016
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 81:4, s. 773-783
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Tidskriftsartikel (refereegranskat)abstract
- AimThe aim of the study was to examine mortality risk associated with use of antidepressants and antipsychotics classified with torsades de pointes (TdP) risk in elderly. MethodsA matched case-control register study was conducted in people 65 years and older dying outside hospital from 2008-2013 (n=286092) and matched controls (n=1430460). The association between prescription of antidepressants and antipsychotics with various TdP risk according to CredibleMeds () and all-cause mortality was studied by multivariate conditional logistic regression adjusted for comorbidity and several other confounders. ResultsUse of antidepressants classified with known or possible TdP risk, was associated with higher adjusted risk for mortality (OR 1.53, 95% CI 1.51, 1.56 and OR 1.63, 95% CI 1.61, 1.67, respectively) compared with antidepressants classified with conditional TdP risk (OR 1.25, 95% CI 1.22, 1.28) or without TdP classification (OR 0.99, 95% CI 0.94, 1.05). Antipsychotics classified with known TdP risk were associated with higher risk (OR 4.57, 95% CI 4.37, 4.78) than antipsychotics with possible risk (OR 2.58, 95% CI 2.52, 2.64) or without TdP classification (OR 2.14, 95% CI 2.03, 2.65). The following risk ranking was observed for commonly used antidepressants: mirtazapine > citalopram > sertraline > amitriptyline and for antipsychotics: haloperidol > risperidone >olanzapine > quetiapine. ConclusionThe CredibleMeds system predicted drug-associated risk for mortality in the elderly at the risk class level. Among antipsychotics, haloperidol, and among antidepressants, mirtazapine and citalopram, were associated with the highest risks. The results suggest that the TdP risk with antidepressants and antipsychotics should be taken into consideration when prescribing to the elderly.
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| 6. |
- Gustafson, Johan, et al.
(författare)
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A high pressure x-ray photoelectron spectroscopy study of CO oxidation over Rh(100).
- 2013
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 26:5
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the oxidation of CO over Rh(100) using high pressure x-ray photoelectron spectroscopy under CO and O2 pressures ranging from 0.01 to 1 mbar. The results show a very low or no conversion for the CO covered surface found at low temperatures, while the activity rises slightly when the temperature is high enough for some CO to desorb, exposing surface sites for dissociative O2 adsorption. As the temperature is increased further, more CO desorbs and oxygen replaces CO as the dominating species at the surface. At the same time we find a sudden increase in the reactivity, such that all CO that reaches the surface is instantly transformed into CO2. We find that the O coverage in the active state is highly dependent on the total pressure and, although we do not detect any presence of a surface oxide as in previous surface x-ray diffraction studies, the highest O coverage indicates that the surface is close to being oxidized.
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| 7. |
- Johnell, Kristina, et al.
(författare)
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Psychotropic drugs and the risk of fall injuries, hospitalisations and mortality among older adults
- 2017
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Ingår i: International Journal of Geriatric Psychiatry. - : Wiley. - 0885-6230 .- 1099-1166. ; 32:4, s. 414-420
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveTo investigate whether psychotropics are associated with an increased risk of fall injuries, hospitalizations, and mortality in a large general population of older adults.MethodsWe performed a nationwide matched (age, sex, and case event day) case–control study between 1 January and 31 December 2011 based on several Swedish registers (n = 1,288,875 persons aged ≥65 years). We used multivariate conditional logistic regression adjusted for education, number of inpatient days, Charlson co-morbidity index, dementia and number of other drugs.ResultsAntidepressants were the psychotropic most strongly related to fall injuries (ORadjusted: 1.42; 95% CI: 1.38–1.45) and antipsychotics to hospitalizations (ORadjusted: 1.22; 95% CI: 1.19–1.24) and death (ORadjusted: 2.10; 95% CI: 2.02–2.17). Number of psychotropics was associated with increased the risk of fall injuries, (4 psychotropics vs 0: ORadjusted: 1.53; 95% CI: 1.39–1.68), hospitalization (4 psychotropics vs 0: ORadjusted: 1.27; 95% CI: 1.22–1.33) and death (4 psychotropics vs 0: ORadjusted: 2.50; 95% CI: 2.33–2.69) in a dose–response manner. Among persons with dementia (n = 58,984), a dose–response relationship was found between number of psychotropics and mortality risk (4 psychotropics vs 0: ORadjusted: 1.99; 95% CI: 1.76–2.25).ConclusionsOur findings support a cautious prescribing of multiple psychotropic drugs to older patients. © 2016 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons, Ltd.
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| 8. |
- Kamal, Chinnathambi, et al.
(författare)
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Core-Level Binding Energy Reveals Hydrogen Bonding Configurations of Water Adsorbed on TiO2 (110) Surface
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 126:1
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Tidskriftsartikel (refereegranskat)abstract
- Using x-ray photoelectron spectroscopy of the oxygen 1s core level, the ratio between intact (D2O) and dissociated (OD) water in the hydrated stoichiometric TiO2 (110) surface is determined at varying coverage and temperature. In the submonolayer regime, both the D2O:OD ratio and the core-level binding energy of D2O (Delta BE) decrease with temperature. The observed variations in Delta BE are shown with density functional theory to be governed crucially and solely by the local hydrogen bonding environment, revealing a generally applicable classification and details about adsorption motifs.
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| 9. |
- Källén, Bengt, et al.
(författare)
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The Use of Central Nervous System Active Drugs During Pregnancy
- 2013
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Ingår i: Pharmaceuticals. - : MDPI AG. - 1424-8247. ; 6:10, s. 1221-1286
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Forskningsöversikt (refereegranskat)abstract
- CNS-active drugs are used relatively often during pregnancy. Use during early pregnancy may increase the risk of a congenital malformation; use during the later part of pregnancy may be associated with preterm birth, intrauterine growth disturbances and neonatal morbidity. There is also a possibility that drug exposure can affect brain development with long-term neuropsychological harm as a result. This paper summarizes the literature on such drugs used during pregnancy: opioids, anticonvulsants, drugs used for Parkinson’s disease, neuroleptics, sedatives and hypnotics, antidepressants, psychostimulants, and some other CNS-active drugs. In addition to an overview of the literature, data from the Swedish Medical Birth Register (1996–2011) are presented. The exposure data are either based on midwife interviews towards the end of the first trimester or on linkage with a prescribed drug register. An association between malformations and maternal use of anticonvulsants and notably valproic acid is well known from the literature and also demonstrated in the present study. Some other associations between drug exposure and outcome were found.
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| 10. |
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