| 1. |
- Navarro Navarrete, Jose Eduardo, 1988-
(author)
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Precise measurements of electron affinities using Laser Photodetachment Threshold Spectroscopy
- 2023
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Licentiate thesis (other academic/artistic)abstract
- In this work we have performed Laser Photodetachment Threshold Spectroscopy (LPTS) to determine the electron affinities of the atomic species $^{133}$Cs and $^{16}$O with high precision. The negative ion of Cesium has been produced and investigated at the Gothenburg University Negative Ion and Laser LAboratory (GUNILLA) while the Oxygen anion have been studied in the Double ElectroStatic Ion Ring ExpEriment (DESIREE) at Stockholm University. Pilot studies have also been carried out to measure the electron affinity of complex molecular systems in DESIREE. Specifically, we have studied the beautifully symmetric fullerene C$_{60}^-$ negative ion and its spontaneous and laser induced decays. A preliminary analysis suggests that DESIREE's internal temperature of $\unit{13}{\kelvin}$ may allow an efficient cooling of these initially created hot molecules on time scales of a few seconds. This is a key aspect in measuring detachment thresholds as cooling suppresses hot band contributions associated with vibrationally excited states. Therefore, photodetachment techniques of the types successfully used for atomic species can be implemented for molecules. The preliminary results appear to settle a matter of disagreement in the literature concerning the most precise method to measure the EA of C$_{60}$, that is, LPTS or Photodetachment Electron Spectroscopy (PES).
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| 2. |
- Engström, Gunnar, et al.
(author)
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Pulmonary function and atherosclerosis in the general population : causal associations and clinical implications
- 2024
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In: European Journal of Epidemiology. - : Springer Nature. - 0393-2990 .- 1573-7284. ; 39:1, s. 35-49
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Journal article (peer-reviewed)abstract
- Reduced lung function is associated with cardiovascular mortality, but the relationships with atherosclerosis are unclear. The population-based Swedish CArdioPulmonary BioImage study measured lung function, emphysema, coronary CT angiography, coronary calcium, carotid plaques and ankle-brachial index in 29,593 men and women aged 50–64 years. The results were confirmed using 2-sample Mendelian randomization. Lower lung function and emphysema were associated with more atherosclerosis, but these relationships were attenuated after adjustment for cardiovascular risk factors. Lung function was not associated with coronary atherosclerosis in 14,524 never-smokers. No potentially causal effect of lung function on atherosclerosis, or vice versa, was found in the 2-sample Mendelian randomization analysis. Here we show that reduced lung function and atherosclerosis are correlated in the population, but probably not causally related. Assessing lung function in addition to conventional cardiovascular risk factors to gauge risk of subclinical atherosclerosis is probably not meaningful, but low lung function found by chance should alert for atherosclerosis.
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| 3. |
- Evangelou, Evangelos, et al.
(author)
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Genetic analysis of over 1 million people identifies 535 new loci associated with blood pressure traits.
- 2018
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:10, s. 1412-1425
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Journal article (peer-reviewed)abstract
- High blood pressure is a highly heritable and modifiable risk factor for cardiovascular disease. We report the largest genetic association study of blood pressure traits (systolic, diastolic and pulse pressure) to date in over 1 million people of European ancestry. We identify 535 novel blood pressure loci that not only offer new biological insights into blood pressure regulation but also highlight shared genetic architecture between blood pressure and lifestyle exposures. Our findings identify new biological pathways for blood pressure regulation with potential for improved cardiovascular disease prevention in the future.
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| 4. |
- Schmidt, Lisa, 1958-
(author)
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Samarbete mellan kund och företagshälsovård : Mekanismer av betydelse för förebyggande arbetsmiljöarbete
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Enligt arbetsmiljölagen ska arbetsgivare när det saknas kunskap och kompetens i det systematiska arbetsmiljöarbetet (SAM) anlita en företagshälsovård (FHV) eller liknande resurs. Detta bygger på en programteori där FHV förväntas vara den externa resurs som behövs för arbetsgivare och arbetsplatser i arbetsmiljöarbetet. Samarbetet och FHVs stöd ska generera god arbetsmiljö och hälsa hos kunderna. Forskning om hur detta samarbete fungerar är begränsad. Avhandlingens syfte är att utforska om FHV fungerar som stöd i kundens förebyggande arbetsmiljö-arbete och att identifiera mekanismer som har betydelse för samarbetet mellan FHV och kund. Mer precist har avhandlingen syftat till att öka kunskap och förståelse för om lagens intention uppfylls. Datainsamlingen i de fyra kvalitativa fallstudierna utfördes med hjälp av semistrukturerade och tematiska intervjuer, telefonintervjuer och gruppintervjuer. Empirin samlades in i små- och stora företag samt inom den offentliga sektorn och fokuserade även på vilken betydelse avtalet har för samarbetet. Intervjuerna har genomförts med ledning, chefer och skyddsombud samt HR-personal i deltagande verksamheter samt FHV professioner i kundens FHV. Intervjuerna har analyserats med kvalitativ innehållsanalys och det sammanlagda resultatet analyserades med hjälp av realistisk utvärdering. Resultatet visar att samarbete och FHVs stöd i förebyggande SAM brister. Förändrade styrformer i offentlig sektor; New Public Management och HR transformationen identifieras som kontextuella förutsättningar som påverkar samarbetet. I den realistiska utvärderingen identifierades mekanismer som positivt eller negativt påverkar samarbetet mellan FHV och kund. Mekanismer som påverkar samarbete positivt är; att det finns en fungerande samverkan och SAM hos kunden och att FHV får information och tillgång till kundens inre processer. Att FHV har en oberoende ställning med kontakter på flera nivåer i verksamheten är andra mekanismer som påverkar samarbete positivt. Att ledningen är engagerad i samarbetet med FHV och att avtalen stöder samarbetet bidrar också positivt till ett framgångsrikt samarbete. Ytterligare mekanismer som gynnsamt påverkar samarbete är att det finns kontinuerliga uppföljningar där tjänster och service kontinuerligt stäms av och anpassas efter kundens behov. En viktig mekanism som påverkar samarbetet positivt är att HR stöder samverkan och SAM i kundföretaget. Identifierade mekanismer som påverkar samarbete negativt är att SAM och samverkan på arbetsplatsen mellan arbetsgivare och arbetstagare brister. Andra mekanismer som negativt påverkar är att ledningen inte är engagerad i samarbetet och att FHV inte får ta del av kundens SAM. Samarbetet påverkas även negativt när HR definierar avtalsinnehåll och är enda kontakt med FHV. En ytterligare mekanism som påverkar samarbetet negativt är att kunden upplever ett bristande förtroende; att FHV saknar kompetens. Ett antal mekanismer har även identifierats som påverkar samarbete negativt mellan FHV och småföretag. Bland annat saknas samverkan mellan arbetsgivare och arbetstagare i stor utsträckning och småföretagen arbetar inte systematiskt med sin arbetsmiljö. Detta innebär att FHV inte fungerar som stöd i SAM utan de tjänster som används består framför allt av hälsoundersökningar. Samma mekanismer som påverkar samarbetet negativt framkommer i den offentliga sektorn; när samverkan och SAM saknas på arbetsplatsen, används FHV främst till individuella hälsofrämjande tjänster och rehabilitering. Andra mekanismer som påverkar samarbetet negativt i den offentliga sektorn är bristen på kunskap om samverkan och SAM hos både HR och skyddsombud. Det finns en otydlighet kring varandras roller som påverkar samarbetet negativt. Även kundens föreställning om FHV; att de uppfattas sakna kompetens och vara en efterhjälpande resurs, påverkar samarbetet negativt. Slutsatserna från avhandlingen visar att samarbetet mellan FHV och kund i stor utsträckning inte stöder förebyggande SAM. I analysen identifieras ett antal mekanismer som påverkar samarbetet mellan FHV och kund, både positivt och negativt. Framför allt kunskap om arbetsmiljö, en fungerande samverkan och SAM identifieras som viktiga mekanismer som på ett positivt sätt bidrar till att nå ett framgångsrikt samarbete.
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| 5. |
- Bergström, Göran, 1964, et al.
(author)
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Body weight at age 20 and in midlife is more important than weight gain for coronary atherosclerosis: Results from SCAPIS.
- 2023
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In: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 373, s. 46-54
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Journal article (peer-reviewed)abstract
- Elevated body weight in adolescence is associated with early cardiovascular disease, but whether this association is traceable to weight in early adulthood, weight in midlife or to weight gain is not known. The aim of this study is to assess the risk of midlife coronary atherosclerosis being associated with body weight at age 20, body weight in midlife and body weight change.We used data from 25,181 participants with no previous myocardial infarction or cardiac procedure in the Swedish CArdioPulmonary bioImage Study (SCAPIS, mean age 57 years, 51% women). Data on coronary atherosclerosis, self-reported body weight at age 20 and measured midlife weight were recorded together with potential confounders and mediators. Coronary atherosclerosis was assessed using coronary computed tomography angiography (CCTA) and expressed as segment involvement score (SIS).The probability of having coronary atherosclerosis was markedly higher with increasing weight at age 20 and with mid-life weight (p<0.001 for both sexes). However, weight increase from age 20 until mid-life was only modestly associated with coronary atherosclerosis. The association between weight gain and coronary atherosclerosis was mainly seen in men. However, no significant sex difference could be detected when adjusting for the 10-year delay in disease development in women.Similar in men and women, weight at age 20 and weight in midlife are strongly related to coronary atherosclerosis while weight increase from age 20 until midlife is only modestly related to coronary atherosclerosis.
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| 6. |
- Ekblom Bak, Elin, 1981-, et al.
(author)
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Accelerometer derived physical activity patterns in 27.890 middle‐aged adults : The SCAPIS cohort study
- 2022
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In: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 32:5, s. 866-880
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Journal article (peer-reviewed)abstract
- The present study aims to describe accelerometer-assessed physical activity (PA) patterns and fulfillment of PA recommendations in a large sample of middle-aged men and women, and to study differences between subgroups of socio-demographic, socio-economic, and lifestyle-related variables. A total of 27 890 (92.5% of total participants, 52% women, aged 50–64 years) middle-aged men and women with at least four days of valid hip-worn accelerometer data (Actigraph GT3X+, wGT3X+ and wGT3X-BT) from the Swedish CArdioPulmonary bioImage Study, SCAPIS, were included. In total, 54.5% of daily wear time was spent sedentary, 39.1% in low, 5.4% in moderate, and only 0.1% in vigorous PA. Male sex, higher education, low financial strain, born in Sweden, and sedentary/light working situation were related to higher sedentary time, but also higher levels of vigorous PA. High BMI and having multiple chronic diseases associated strongly with higher sedentary time and less time in all three PA intensities. All-year physically active commuters had an overall more active PA pattern. The proportion fulfilling current PA recommendations varied substantially (1.4% to 92.2%) depending on data handling procedures and definition used. Twenty-eight percent was defined as having an “at-risk” behavior, which included both high sedentary time and low vigorous PA. In this large population-based sample, a majority of time was spent sedentary and only a fraction in vigorous PA, with clinically important variations between subgroups. This study provides important reference material and emphasizes the importance of a comprehensive assessment of all aspects of the individual PA pattern in future research and clinical practice.
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| 7. |
- Hentschel, Oliver, et al.
(author)
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Experimental Investigations in the Processing of AISI H11 Powder Blends Enriched with Tungsten Carbide Nanoparticles for the Additive Manufacturing of Tailored Hot Working Tools in the Directed Energy Deposition (DED-LB/M)—Impact of Tungsten Carbide Nanoparticles on Microstructural and Mechanical Characteristics
- 2024
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In: Metals. - : MDPI. - 2075-4701. ; 14:2, s. 188-188
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Journal article (peer-reviewed)abstract
- In this study, the DED-LB/M process of AISI H11 tool steel powder blends modified by adding WC nanoparticles (WC-np) in concentrations of 1, 2.5 and 5 wt.-% was the object of scientific investigations. For this, 30-layer cuboid specimens were manufactured. The overall scientific aim was to examine how the WC-np interact with the steel melt and in the end, influence the processability, microstructure and mechanical properties of produced specimens. The examinations were carried out on both as-built and thermally post-processed specimens. An advanced microstructural analysis (SEM, EDS, EBSD and XRD) revealed that due to the high solubility of WC-np in the molten steel, most of the WC-np appear to have dissolved during the ongoing laser process. Furthermore, the WC-np favor a stronger distortion and finer grain size of martensite in the manufactured specimens. An increase in hardness from about 650 HV1 for the H11 specimen to 780 HV1 for the one manufactured using the powder blend containing 5 wt.-% of WC-np was observed in as-built conditions. In the same way, the compression yield strength enhanced from 1839 MPA to 2188 MPA. The hardness and strength increasing effect of WC-np remained unchanged even after heat treatments similar to those used in industry.
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| 8. |
- Sörman, Erik
(author)
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The silicon vacancy in SiC
- 1997
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Doctoral thesis (other academic/artistic)abstract
- SiC has for decades been considered to be a very promising semiconductor, but several problems related to the material quality, did earlier prevent an exploitation of the supreme electrical characteristics of the material. Now most of these problems have been overcome, high quality material can be grown and research around this material is going through an intense phase of development.The photoluminescence (PL) technique is simple, non-destructive and requires no sample preparation. If a PL signal can be associated with a fundamental defect it certainly is an important piece of information. A fingerprint signal obtainable with such a simple technique is very useful in routine characterisation of the material. In our ambition to reveal the origin of the PL signals from SiC, we have used a technique called optically detected magnetic resonance (ODMR). It is efficient in supplying microscopic information about defects and have enabled us to assign a deep PL band to the silicon vacancy in 3C, 4H and 6H SiC. To be more specific, we argue that the deep PL band originates from internal transitions of the silicon vacancy in its neutral charge state.SiC is the classical example of polytypism i. e. it appears in many different but closely related crystal structures. A substitutional atom or a vacancy can therefore occupy sites, with different arrangements of their neighbours. If a defect is sensitive to its immediate neighbourhood, the signals from the different sites can usually be separated and new possibilities opens up for a materials scientist. A certain defect system can then be investigated and compared between the polytypes and much more about how the local environment of the defect affects its properties can be learned, than otherwise would have been possible.Here we have been able to investigate the signals from the silicon vacancy in 3C, 4H and 6H SiC and by comparing the characteristics of the signals from the different sites, we have been able to correlate the individual signals to the corresponding sites in the 4H and 6H crystals (in the 3C crystal there is just one site). There are some pronounced differences in the signals from the different sites. Only the PL lines from the sites with a cubic environment are split by applied stress while the ODMR signals from the sites with a hexagonal environment have a stronger relation to the symmetry axis of the crystal.Substitutional nitrogen is a shallow donor in SiC. Our magnetic resonance measurements show that the loosely bound electron of the nitrogen atom is transferred to various deep defects. This direct transfer of electrons from a shallow defect to deeper ones opens up new efficient recombination channels. This type of recombination channels is not included in standard recombination models.
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