| 1. |
- Andersson, Daniel P., et al.
(författare)
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Relation among hypertriglyceridaemia, cardiometabolic disease, and hereditary factors : design and rationale of the Stockholm hyperTRIglyceridaemia REGister study
- 2024
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Ingår i: European Heart Journal Open. - : Oxford University Press. - 2752-4191. ; 4:2
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Tidskriftsartikel (refereegranskat)abstract
- AimsHypertriglyceridaemia (hTG) is associated with atherosclerotic cardiovascular disease, pancreatitis, and non-alcoholic fatty liver disease (NAFLD) in large population-based studies. The understanding of the impact of hereditary hTG and cardiometabolic disease status on the development of hTG and its associated cardiometabolic outcomes is more limited. We aimed to establish a multigenerational cohort to enable studies of the relationship between hTG, cardiometabolic disease and hereditary factors.Methods and resultsThe population-based observational Stockholm hyperTRIglyceridaemia REGister (STRIREG) study includes 1 460 184 index individuals who have measured plasma triglycerides in the clinical routine in Region Stockholm, Sweden, between 1 January 2000 and 31 December 2021. The laboratory measurements also included basic haematology, blood lipid panel, liver function tests, and HbA1c. Using the Swedish Multi-Generation register, 2 147 635 parents and siblings to the indexes were identified to form the complete study cohort. Laboratory data from participants were combined with data from several national registers that provided information on the cause of death, medical diagnoses, dispensed medicines, and socioeconomic factors including country of birth, education level, and marital status.ConclusionThe multi-generational longitudinal STRIREG cohort provides a unique opportunity to investigate different aspects of hTG as well as heredity for other metabolic diseases. Important outcome measures include mortality, cardiovascular mortality, major cardiovascular events, development of incident diabetes, and NAFLD. The STRIREG study will provide a deeper understanding of the impact of hereditary factors and associated cardiometabolic complications.
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| 2. |
- Bergström, Ingrid, et al.
(författare)
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Back extensor training increases muscle strength in postmenopausal women with osteoporosis, kyphosis and vertebral fractures
- 2011
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Ingår i: Advances in Physiotherapy. - : Informa Healthcare. - 1403-8196 .- 1651-1948. ; 13:3, s. 110-117
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Tidskriftsartikel (refereegranskat)abstract
- We determined the efficacy of a back muscle extensor strengthening program on the back muscle extensor strength, kyphosis, height and thoracic expansion in women with at least one vertebral fracture, kyphosis and osteoporosis. Thirty-six patients were included and randomized to a control or a training group. The training focused on back muscle extensor strengthening program for 1 h, twice a week for 4 months and was performed by a physiotherapist. The main outcome measure was the back muscle extensor strength. In an intention-to-treat analysis no significant effects on back muscle strength in the training group vs. controls could be seen (p = 0.74). In a per-protocol analysis (n = 28), the training group increased back muscle strength from 290 ± 87 to 331 ± 89 N while the control group showed no improvement. After adjusting for the strength at baseline, a significant effect of training could be demonstrated (p = 0.029). When comparing the heights between the groups a significant group × time interaction was observed (p = 0.012) where the training women increased their mean height with 0.3 cm (p = 0.101) and controls decreased 0.44 cm (p = 0.045). The training group improved their thoracic expansion compared with baseline (p = 0.03). No effect of training on kyphosis was seen. In conclusion, a 4-months back extensor training program can improve back strength and seems to maintain height and thoracic expansion.
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| 3. |
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| 4. |
- Besharat, Zahra, et al.
(författare)
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Dehydrogenation of methanol on Cu2O(100) and (111)
- 2017
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 146:24
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption and desorption of methanol on the (111) and (100) surfaces of Cu2O have been studied using high-resolution photoelectron spectroscopy in the temperature range 120-620 K, in combination with density functional theory calculations and sum frequency generation spectroscopy. The bare (100) surface exhibits a (3,0; 1,1) reconstruction but restructures during the adsorption process into a Cu-dimer geometry stabilized by methoxy and hydrogen binding in Cu-bridge sites. During the restructuring process, oxygen atoms from the bulk that can host hydrogen appear on the surface. Heating transforms methoxy to formaldehyde, but further dehydrogenation is limited by the stability of the surface and the limited access to surface oxygen. The (root 3 x root 3)R30 degrees-reconstructed (111) surface is based on ordered surface oxygen and copper ions and vacancies, which offers a palette of adsorption and reaction sites. Already at 140 K, a mixed layer of methoxy, formaldehyde, and CHxOy is formed. Heating to room temperature leaves OCH and CHx. Thus both CH-bond breaking and CO-scission are active on this surface at low temperature. The higher ability to dehydrogenate methanol on (111) compared to (100) is explained by the multitude of adsorption sites and, in particular, the availability of surface oxygen.
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| 5. |
- Brinck, Ingar, et al.
(författare)
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Kreativitet och nyföretagande
- 2009
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Ingår i: Entreprenörskap och företagsetablering. - 9789144021478 ; , s. 101-130
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Kreativitet behandlas ur kognitiv-psykologisk synvinkel. Kapitlet beskriver kreativitetens natur och förklarar vad kreativ förmåga kan tillföra i affärssammanhang. Kapitlet fokuserar både den kreativa processen i allmänhet och förmågans speciella roll för nyföretagande. Syftet är att ge en beskrivning av kreativitet som inte bara är korrekt, utan även kan fungera som ett verktyg i entreprenörens vardag. Inledningsvis tar kapitlet upp mytbildningen kring kreativitet, och diskuterar dess roll för entreprenörskapet samt företagande i stort. Därefter beskrivs den kreativa processens förlopp. En modell av processen presenteras som tydliggör den och dessutom kan användas som ett praktiskt verktyg. De tre grundläggande momenten i den kreativa processen behandlas i detalj ― behovsanalysen, idégenereringen och idévärderingen. Två grundläggande principer för idégenerering förs fram, liksom olika typer av kritierier för att värdera idéer. Slutligen diskuteras egenskaperna hos både yttre och interna kreativa miljöer. Allra sist i kapitlet återfinns några steg-för-steg metoder för att öva idégenerering: Egenskapspussel, Slumpordsassociation och Negativ idégenerering.
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| 6. |
- Brinck, Jonas, et al.
(författare)
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E78.0A – en unik, ny ICD-10-kod för familjär hyperkolesterolemi : [Sweden introduces a new specific ICD-10 code for the disease familial hypercholesterolemia]
- 2019
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Ingår i: Läkartidningen. - Stockholm, Sweden : Läkartidningen Förlag. - 0023-7205 .- 1652-7518. ; 116
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Forskningsöversikt (refereegranskat)abstract
- At the turn of the year 2018/19, a new ICD-10 code (E78.0A) will be introduced in Sweden for the hereditary blood lipid disorder familial hypercholesterolemia (FH). Patients with FH have a significantly increased risk of developing atherosclerotic disease, such as myocardial infarction before the age of 50. However, early diagnosis and start of treatment of FH can ameliorate the disease's negative long term effects. The Swedish National Board of Health and Welfare gave in its guidelines from 2015 a high priority to the work of identifying and diagnosing individuals with FH in the general population. The introduction of the ICD-10 code E78.0A for FH may, when properly used, be an effective tool in this work.
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| 7. |
- Brinck, Jonas
(författare)
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The expression and regulation of hyaluronan synthases and their role in glycosaminoglycan synthesis
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The glycosaminoglycan hyaluronan is an essential component of the extracellular matrix in all higher organisms, affecting cellular processes such as migration, proliferation and differentiation. Hyaluronan is synthesized by a plasma membrane bound hyaluronan synthase (HAS) which exists in three genetic isoforms. This thesis focuses on the understanding of the hyaluronan biosynthesis by studies on the expression and regulation of the HAS proteins.In order to characterize the structural and functional properties of the HAS isoforms we developed a method to solubilize HAS protein(s) while retaining enzymatic activity. The partially purified HAS protein is, most likely, not asscociated covalently with other components. Cells transfected with cDNAs for HAS1, HAS2 and HAS3 were studied and all three HAS isozymes were able to synthesize high molecular weight hyaluronan chains in intact cells. The regulation of the hyaluronan chain length involves cell specific elements as well as external stimulatory factors. HAS3 transfected cells with high hyaluronan production exhibit reduced migration capacity and reduced amounts of a cell surface hyaluronan receptor molecule (CD44) compared to wild-type cells.The three HAS isoforms were studied and shown to be differentially expressed and regulated in response to external stimuli. Platelet derived growth factor (PDGF-BB) and transforming growth factor (TGF-β1) are important regulators of HAS at both the transcriptional and translational level. The HAS2 isoform is the isoform most susceptible to external regulation.The role of the UDP-glucose dehydrogenase in mammalian glycosaminoglycan biosynthesis was assessed. The enzyme is essential for hyaluronan, heparan sulfate and chondroitin sulfate biosynthesis, but does not exert a rate-limiting effect.
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| 8. |
- Brinck, Jonas W., et al.
(författare)
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High-density lipoprotein from end-stage renal disease patients exhibits superior cardioprotection and increase in sphingosine-1-phosphate
- 2018
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Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 48:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic kidney disease (CKD) exacerbates the risk of death due to cardiovascular disease (CVD). Modifications to blood lipid metabolism which manifest as increases in circulating triglycerides and reductions in high-density lipoprotein (HDL) cholesterol are thought to contribute to increased risk. In CKD patients, higher HDL cholesterol levels were not associated with reduced mortality risk. Recent research has revealed numerous mechanisms by which HDL could favourably influence CVD risk. In this study, we compared plasma levels of sphingosine-1-phosphate (S1P), HDL-associated S1P (HDL-S1P) and HDL-mediated protection against oxidative stress between CKD and control patients. Methods: High-density lipoprotein was individually isolated from 20 CKD patients and 20 controls. Plasma S1P, apolipoprotein M (apoM) concentrations, HDL-S1P content and the capacity of HDL to protect cardiomyocytes against doxorubicin-induced oxidative stress in vitro were measured. Results: Chronic kidney disease patients showed a typical profile with significant reductions in plasma HDL cholesterol and albumin and an increase in triglycerides and pro-inflammatory cytokines (TNF-alpha and IL-6). Unexpectedly, HDL-S1P content (P = .001) and HDL cardioprotective capacity (P = .034) were increased significantly in CKD patients. Linear regression analysis of which factors could influence HDL-S1P content showed an independent, negative and positive association with plasma albumin and apoM levels, respectively. Discussion: The novel and unexpected observation in this study is that uremic HDL is more effective than control HDL for protecting cardiomyocytes against oxidative stress. It is explained by its higher S1P content which we previously demonstrated to be the determinant of HDL-mediated cardioprotective capacity. Interestingly, lower concentrations of albumin in CKD are associated with higher HDL-S1P.
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| 9. |
- Correa, Yubexi, et al.
(författare)
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High-Density Lipoprotein function is modulated by the SARS-CoV-2 spike protein in a lipid-type dependent manner
- 2023
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 645, s. 627-638
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Tidskriftsartikel (refereegranskat)abstract
- There is a close relationship between the SARS-CoV-2 virus and lipoproteins, in particular high-density lipoprotein (HDL). The severity of the coronavirus disease 2019 (COVID-19) is inversely correlated with HDL plasma levels. It is known that the SARS-CoV-2 spike (S) protein binds the HDL particle, probably depleting it of lipids and altering HDL function. Based on neutron reflectometry (NR) and the ability of HDL to efflux cholesterol from macrophages, we confirm these observations and further identify the preference of the S protein for specific lipids and the consequent effects on HDL function on lipid exchange ability. Moreover, the effect of the S protein on HDL function differs depending on the individuals lipid serum profile. Contrasting trends were observed for individuals presenting low triglycerides/high cholesterol serum levels (LTHC) compared to high triglycerides/high cholesterol (HTHC) or low triglycerides/low cholesterol serum levels (LTLC). Collectively, these results suggest that the S protein interacts with the HDL particle and, depending on the lipid profile of the infected individual, it impairs its function during COVID-19 infection, causing an imbalance in lipid metabolism.
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| 10. |
- Halenius, Engelbert, 1700-1767
(författare)
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Dissertationis philosophicæ, de mensura veritatis, bonitatis, perfectionis, et moralitatis, invenienda, partem IV:m ... candidæ bonorum disquisitioni sistunt, auctor Engelbertus Laur. Halenius ... atque respondens Jonas Brinck, Dalia-Wermelandus. In audit. Gust. maj. ad diem 10. decemb. an. MDCCXL., P. 4
- 1740
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
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| 11. |
- Halldin Stenlid, Joakim, et al.
(författare)
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Reactivity at the Cu2O(100):Cu-H2O interface : a combined DFT and PES study
- 2016
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 18:44, s. 30570-30584
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Tidskriftsartikel (refereegranskat)abstract
- The water-cuprite interface plays an important role in dictating surface related properties. This not only applies to the oxide, but also to metallic copper, which is covered by an oxide film under typical operational conditions. In order to extend the currently scarce knowledge of the details of the water-oxide interplay, water interactions and reactions on a common Cu2O(100):Cu surface have been studied using high-resolution photoelectron spectroscopy (PES) as well as Hubbard U and dispersion corrected density functional theory (PBE-D3+U) calculations up to a bilayer water coverage. The PBE-D3+U results are compared with PBE, PBE-D3 and hybrid HSE06-D3 calculation results. Both computational and experimental results support a thermodynamically favored, and H2O coverage independent, surface OH coverage of 0.25-0.5 ML, which is larger than the previously reported value. The computations indicate that the results are consistent also for ambient temperatures under wet/humid and oxygen lean conditions. In addition, both DFT and PES results indicate that the initial (3,0; 1,1) surface reconstruction is lifted upon water adsorption to form an unreconstructed (1 x 1) Cu2O(100) structure.
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| 12. |
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| 13. |
- Littmann, Karin, et al.
(författare)
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Plasma lipoprotein(a) measured in the routine clinical care is associated to atherosclerotic cardiovascular disease during a 14-year follow-up.
- 2021
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Ingår i: European Journal of Preventive Cardiology. - : Oxford University Press. - 2047-4873 .- 2047-4881. ; 28:18, s. 2038-2047
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To investigate plasma lipoprotein(a) [Lp(a)] levels measured in routine clinical care and their association with mortality and cardiovascular disease.METHODS AND RESULTS: This retrospective registry-based observational cohort study includes all individuals with plasma Lp(a) results measured at the Karolinska University Laboratory 2003-17. Outcome data were captured in national outcome registries. Levels of Lp(a) expressed in mass or molar units were examined separately. In adjusted Cox regression models, association between deciles of plasma Lp(a) concentrations, mortality, and cardiovascular outcomes were assessed. A total of 23 398 individuals [52% females, mean (standard deviation) age 55.5 (17.2) years, median Lp(a) levels 17 mg/dL or 19.5 nmol/L] were included. Individuals with an Lp(a) level >90th decile (>90 mg/dL or >180 nmol/L) had hazard ratios (95% confidence interval) of 1.25 (1.05-1.50) for major adverse cardiovascular events (P = 0.013), 1.37 (1.14-1.64) for atherosclerotic cardiovascular disease (P = 0.001), and 1.62 (1.28-2.05) for coronary artery disease (P ≤ 0.001), compared to individuals with Lp(a) ≤50th decile. No association between Lp(a) and mortality, peripheral artery disease, or ischaemic stroke was observed.CONCLUSION: High Lp(a) levels are associated with adverse cardiovascular disease outcomes also in individuals with Lp(a) measured in routine clinical care. This supports the 2019 ESC/EAS recommendation to measure Lp(a) at least once during lifetime to assess cardiovascular risk and implies the need for intensive preventive therapy in patients with elevated Lp(a).
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| 14. |
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| 15. |
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| 16. |
- Sjuls, Simon, et al.
(författare)
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Effective cholesterol lowering after myocardial infarction in patients with nephrotic syndrome may require a multi-pharmacological approach : a case report
- 2021
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Ingår i: European Heart Journal - Case Reports. - : Oxford University Press. - 2514-2119. ; 5:5
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Tidskriftsartikel (refereegranskat)abstract
- Background Nephrotic syndrome causes severe hypercholesterotaemia due to increased production and altered clearance of lipoproteins from the liver. It is challenging for patients with nephrotic syndrome and coronary heart disease to meet LDL-cholesterol (LDL-C) goals for secondary prevention with conventional lipid-lowering therapy. Case summary We present a man with nephrotic syndrome caused by focal segmental glomerular sclerosis (FSGS) and hypercholesterolaemia. He presented at the emergency room (ER) with an ST-elevation myocardial infarction at the age of 26. On follow-up, the patient had persistent hyperchotesterotaemia [LDL-C 3.9 mmot/L and tipoprotein(a) 308 nmol/L] despite a combination of lipid-lowering therapy with atorvastatin 80 mg/day and ezetimibe 10 mg/ day. Addition of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitory antibody evolocumab 140 mg bi-monthly did not improve cholesterol levels. However, after addition of the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagtiflozin 10 mg/day on top of other anti-proteinuric treatments, the patients proteinuria was reduced and a dramatic drop in LDL-C level by 3.2 -0.6 mmoUL (-81%) was observed when evolocumab was re-introduced. Discussion We show that target LDL-C levels were obtained in this patient with therapy-resistant FSGS and hypercholesterolaemia following multi-pharmacological treatment with SGLT2 and PCSK9 inhibitors on top of conventional lipid-lowering therapy. The SGLT2-inhibitor reduced proteinuria and, speculatively, also reduced urinary loss of PCSK9antibody. Therefore, in patients with nephrotic syndrome and cardiovascular disease novel therapeutic options to manage proteinuria could be considered to improve the efficacy of the lipid-lowering therapy, especially when the protein-based PCSK9 inhibitors are used.
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| 17. |
- Soldemo, Markus, et al.
(författare)
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Interaction of sulfur dioxide and near-ambient pressures of water vapor with cuprous oxide surfaces
- 2017
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 121:43, s. 24011-24024
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of water vapor and sulfur dioxide (SO2) with single crystal cuprous oxide (Cu2O) surfaces of (100) and (111) termination was studied by photoelectron spectroscopy (PES) and density functional theory (DFT). Exposure to near-ambient pressures of water vapor, at 5 × 10-3 %RH and 293 K, hydroxylates both Cu2O surfaces with OH coverage up to 0.38 copper monolayers (ML) for (100) and 0.25 ML for (111). O 1s surface core level shifts indicate that the hydroxylation lifts the (3,0;1,1) reconstruction of the clean (100) surface. On both clean Cu2O terminations, SO2 adsorbs to unsaturated surface oxygen atoms to form SO3 species with coverage, after a saturating SO2 dose, corresponding to 0.20 ML on the Cu2O(100) surface and 0.09 ML for the Cu2O(111) surface. Our combined DFT and PES results suggest that the SO2 to SO3 transformation is largely facilitated by unsaturated copper atoms at the Cu2O(111) surface. SO3-terminated surfaces exposed to low doses of water vapor (=100 langmuirs) in ultrahigh vacuum show no adsorption or reaction. However, during exposure to near-ambient pressures of water vapor, the SO3 species dissociate, and sulfur replaces a Cu2O lattice oxygen in a reaction that forms Cu2S. The hydroxylation of the Cu2O surfaces is believed to play a central role in the reaction.
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| 18. |
- Soldemo, Markus, et al.
(författare)
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The Surface Structure of Cu2O(100)
- 2016
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:8, s. 4373-4381
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Tidskriftsartikel (refereegranskat)abstract
- Despite the industrial importance of copper oxides, the nature of the (100) surface of Cu2O has remained poorly understood. The surface has previously been subject to several theoretical and experimental studies, but has until now not been investigated by atomically resolved microscopy or high-resolution photoelectron spectroscopy. Here we determine the atomic structure and electronic properties of Cu2O(100) by a combination of multiple experimental techniques and simulations within the framework of density functional theory (DFT). Low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) characterized the three ordered surface structures found. From DFT calculations, the structures are found to be energetically ordered as (3,0;1,1), c(2 x 2), and (1 x 1) under ultrahigh vacuum conditions. Increased oxygen pressures induce the formation of an oxygen terminated (1 x 1) surface structure. The most common termination of Cu2O(100) has previously been described by a (3 root 2 x root 2)R45 degrees unit cell exhibiting a LEED pattern with several missing spots. Through atomically resolved STM, we show that this structure instead is described by the matrix (3,0;1,1). Both simulated STM images and calculated photoemission core level shifts compare favorably with the experimental results.
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| 19. |
- Tissot, H., et al.
(författare)
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Acetic acid conversion to ketene on Cu 2 O(1 0 0): Reaction mechanism deduced from experimental observations and theoretical computations
- 2021
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Ingår i: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 402, s. 154-165
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Tidskriftsartikel (refereegranskat)abstract
- Ketene, a versatile reagent in production of fine and specialty chemicals, is produced from acetic acid. We investigate the synthesis of ketene from acetic acid over the (3,0;1,1) surface of Cu2O(1 0 0) through analysis of the adsorption and desorption characteristics of formic and acetic acids. The results allow us to establish a reaction mechanism for ketene formation. Observations from x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy, and temperature programmed desorption (TPD), supported by a comparison with formic acid results, suggest that acetic acid reacts with Cu2O through deprotonation to form acetate species coordinated to copper sites and hydroxylation of nearby surface oxygen sites. For formic acid the decomposition of adsorbed formate species results in desorption of CO2 and CO while, for acetic acid, high yields of ketene are observed at temperature >500 K. Modeling by density functional theory (DFT) confirms the strong interaction of acetic acid with the (3,0;1,1) surface and the spontaneous dissociation into adsorbed acetate and hydrogen atom species, the latter forming an OH-group. In an identified reaction intermediate ketene binds via all C and O atoms to Cu surface sites, in agreement with interpretations from XPS. In the vicinity of the adsorbate the surface experiences a local reorganization into a c(2 × 2) reconstruction. The total computed energy barrier for ketene formation is 1.81 eV in good agreement with the 1.74 eV obtained from TPD analysis. Our experimental observations and mechanistic DFT studies suggests that Cu2O can operate as an efficient catalyst for the green generation of ketene from acetic acid.
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| 20. |
- Tissot, Heloise, et al.
(författare)
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Acetic acid conversion to ketene on Cu2O(100) : Reaction mechanism deduced from experimental observations and theoretical computations
- 2021
-
Ingår i: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 402, s. 154-165
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Tidskriftsartikel (refereegranskat)abstract
- Ketene, a versatile reagent in production of fine and specialty chemicals, is produced from acetic acid. We investigate the synthesis of ketene from acetic acid over the (3,0;1,1) surface of Cu2O(1 0 0) through analysis of the adsorption and desorption characteristics of formic and acetic acids. The results allow us to establish a reaction mechanism for ketene formation. Observations from x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy, and temperature programmed desorption (TPD), supported by a comparison with formic acid results, suggest that acetic acid reacts with Cu2O through deprotonation to form acetate species coordinated to copper sites and hydroxylation of nearby surface oxygen sites. For formic acid the decomposition of adsorbed formate species results in desorption of CO2 and CO while, for acetic acid, high yields of ketene are observed at temperature >500 K. Modeling by density functional theory (DFT) confirms the strong interaction of acetic acid with the (3,0;1,1) surface and the spontaneous dissociation into adsorbed acetate and hydrogen atom species, the latter forming an OH-group. In an identified reaction intermediate ketene binds via all C and O atoms to Cu surface sites, in agreement with interpretations from XPS. In the vicinity of the adsorbate the surface experiences a local reorganization into a c(2 × 2) reconstruction. The total computed energy barrier for ketene formation is 1.81 eV in good agreement with the 1.74 eV obtained from TPD analysis. Our experimental observations and mechanistic DFT studies suggests that Cu2O can operate as an efficient catalyst for the green generation of ketene from acetic acid.
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| 21. |
- Tissot, Heloise, et al.
(författare)
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Interaction of Atomic Hydrogen with the Cu2O(100) and (111) Surfaces
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 123:36, s. 22172-22180
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Tidskriftsartikel (refereegranskat)abstract
- Reduction of Cu2O by hydrogen is a common preparation step for heterogeneous catalysts; however, a detailed understanding of the atomic reaction pathways is still lacking. Here, we investigate the interaction of atomic hydrogen with the Cu2O(100):(3,0;1,1) and Cu2O(111):(root 3 x root 3)R30 degrees surfaces using scanning tunneling microscopy (STM), low-energy electron diffraction, temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The experimental results are compared to density functional theory simulations. At 300 K, we identify the most favorable adsorption site on the Cu2O(100) surface: hydrogen atoms bind to an oxygen site located at the base of the atomic rows intrinsic to the (3,0;1,1) surface. The resulting hydroxyl group subsequently migrates to a nearby Cu trimer site. TPD analysis identifies H-2 as the principal desorption product. These observations imply that H-2 is formed through a disproportionation reaction of surface hydroxyl groups. The interaction of H with the (111) surface is more complex, including coordination to both Cu+ and O-CUS sites. STM and XPS analyses reveal the formation of metallic copper clusters on the Cu2O surfaces after cycles of hydrogen exposure and annealing. The interaction of the Cu clusters with the substrate is notably different for the two surface terminations studied: after annealing, the Cu clusters coalesce on the (100) termination, and the (3,0;1,1) reconstruction is partially recovered. Clusters formed on the (111) surface are less prone to coalescence, and the (root 3 x root 3)R30 degrees reconstruction was not recovered by heat treatment, indicating a weaker Cu cluster to support interaction on the (100) surface.
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| 22. |
- Tissot, Heloise, et al.
(författare)
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The Surface Structure of Cu2O(100) : Nature of Defects
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:13, s. 7696-7704
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Tidskriftsartikel (refereegranskat)abstract
- The Cu2O(100) surface is most favorably terminated by a (3,0;1,1) reconstruction under ultrahigh-vacuum conditions. As most oxide surfaces, it exhibit defects, and it is these sites that are focus of attention in this study. The surface defects are identified, their properties are investigated, and procedures to accurately control their coverage are demonstrated by a combination of scanning tunneling microscopy (STM) and simulations within the framework of density functional theory (DFT). The most prevalent surface defect was identified as an oxygen vacancy. By comparison of experimental results, formation energies, and simulated STM images, the location of the oxygen vacancies was identified as an oxygen vacancy in position B, located in the valley between the two rows of oxygen atoms terminating the unperturbed surface. The coverage of defects is influenced by the surface preparation parameters and the history of the sample. Furthermore, using low-energy electron beam bombardment, we show that the oxygen vacancy coverage can be accurately controlled and reach a complete surface coverage (1 per unit cell or 1.8 defects per nm(2)) without modification to the periodicity of the surface, highlighting the importance of using local probes when investigating oxide surfaces.
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| 23. |
- Ullén, Petrus
(författare)
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Dissertatio philosophica, de necessitate physica, quam, ... præside ... Mag. Petro Ullén, ... pro gradu, publicæ eruditorum censuræ modeste subjicit Jonas Brinck, Wermelandus. In Auditorio Carolino Majori, ad diem IV. Junii Anni MDCCXLIII. Horis, ante meridiem, solitis.
- 1743
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Wodaje, Tigist, et al.
(författare)
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Higher prevalence of coronary microvascular dysfunction in asymptomatic individuals with high levels of lipoprotein(a) with and without heterozygous familial hypercholesterolaemia
- 2024
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Ingår i: Atherosclerosis. - 0021-9150 .- 1879-1484. ; 389
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Microvascular dysfunction underlies many cardiovascular disease conditions; little is known regarding its presence in individuals with high levels of lipoprotein(a) [Lp(a)]. The aim of the present study was to determine the frequency of microvascular dysfunction among such subjects with and without concomitant familial hypercholesterolemia (FH). Methods: Four groups of asymptomatic individuals aged 30–59 years, without manifest cardiovascular disease, were recruited (n = 30 per group): controls with Lp(a) < 30 nmol/L, mutation-confirmed FH with Lp(a) < 30 nmol/L, or >125 nmol/L, and individuals with isolated Lp(a) > 125 nmol/L. Participants underwent evaluation of myocardial microvascular function by measuring coronary flow reserve (CFR) using transthoracic Doppler echocardiography, and of peripheral microvascular endothelial function by peripheral arterial tonometry. Results: The groups were balanced in age, sex, and body mass index. Each of the three dyslipoproteinaemic groups had a greater proportion of individuals with impaired coronary flow reserve, 30%, compared to 6.7% of controls (p = 0.014). The median CFR levels did not differ significantly between the four groups, however. Cholesterol-lowering treatment time was longer in the individuals with normal than in those with impaired CFR in the FH + Lp(a) > 125 group (p = 0.023), but not in the group with FH + Lp(a) < 30 (p = 0.468). There was no difference in peripheral endothelial function between the groups. Conclusions: Coronary microvascular dysfunction is more prevalent in asymptomatic individuals with isolated Lp(a) elevation and in heterozygous FH both with and without high Lp(a) compared to healthy controls. Cholesterol-lowering treatment could potentially prevent the development of microvascular dysfunction.
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| 25. |
- Woldegiorgis, Andreas, et al.
(författare)
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Polymer-assisted laser desorption/ionization analysis of small molecular weight compounds
- 2004
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Ingår i: Rapid Communications in Mass Spectrometry. - : Wiley. - 0951-4198 .- 1097-0231. ; 18:8, s. 841-852
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Tidskriftsartikel (refereegranskat)abstract
- The use of non-polar, small polymers as matrices for the analysis of low molecular weight compounds in polymer-assisted laser desorption/ionization mass spectrometry (PALDI-MS) is demonstrated. The matrices evaluated were either based on an oligothiophene or a benzodioxin backbone. Metallocenes, polycyclic hydrocarbons, a fluorosurfactant, and a subset of small organic compounds with various functionalities, served as model analytes. The mechanism of ionization charge transfer is discussed and ionization potentials for the matrices in the study have been estimated using density functional theory (DFT) calculations. Some of the results are possibly contradictory to the generally accepted limiting conditions for gas-phase charge-transfer reactions. These results are interpreted in the light of energy pooling. Also a new mass calibration procedure for the lowmass region in positive ion mode is presented, and some aspects of the ionization/desorption process leading to radical cations are studied.
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