Publikationer från Uppsala Universitet
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Troponin I is an independent predictor of cardiovascular events and mortality in haemodialysis patients
No full textBackground: Patients with end-stage kidney disease (ESKD) undergoing haemodialysis (HD) have a high risk of cardiovascular (CV) events. This study evaluated troponin I (hs-cTnI) as a predictor of major adverse cardiac events (MACEs), CV death and all-cause death. Methods: The AURORA trial, a multicentre, randomized, double-blind trial involved 2776 HD patients comparing rosuvastatin with placebo. No significant effect was found on the composite primary endpoint of CV death, non-fatal myocardial infarction or non-fatal stroke. In this post hoc analysis, we analysed the association between baseline hs-cTnI and outcomes using Cox regression analyses. We adjusted for multiple background factors and available biomarkers. Hs-cTnI was log2-transformed and modelled using a four-knot restricted cubic spline. Variables were ordered by their importance in the models using chi 2 value minus degrees of freedom. Results: Baseline median hs-cTnI was 17.3 pg/mL. During follow-up, 734 MACEs, 598 CV deaths, and 1094 total deaths occurred. Patients in the upper quartile of hs-cTnI (>32.6 pg/mL) had significantly higher risk of MACEs [hazard ratio (HR) 1.92; 95% confidence interval (CI) 1.57-2.35], CV death (HR 2.12; 95% CI 1.69-2.66), all-cause death (HR 1.84; 95% CI 1.55-2.17) and non-CV death (HR 1.59; 95% CI 1.23-2.05) after full adjustment compared with those in the lowest quartile (<10.1 pg/mL). Hs-cTnI was identified as the strongest predictor for MACEs, CV death, and all-cause death, but not for non-CV death. Conclusions: Baseline hs-cTnI is a strong and independent predictor for MACEs and death in patients with ESKD undergoing haemodialysis
Isolated Grid-Forming Control of Wave Energy Converter for Island Electrification
No full textAs the world transitions to renewable electrification to reduce CO2 emissions, remote island electrification remains a challenge. Although some islands are connected to the grid, many still rely on fossil fuels for electricity generation. Several studies indicate that renewable energy sources, such as wave energy, have the potential to make these islands self-reliant because of their substantial power potential. However, research on the control of power electronics converters for these systems remains limited. This paper proposes isolated grid-forming control for island electrification to address this gap using a wave energy converter and an energy storage system. Resistive loading control is implemented to optimize the power absorption of the generator. The result illustrates the establishment of the required AC voltage and 50 Hz frequency in the island load, ensuring harmonics compliance with the recommended standards. Experiments were conducted to test and validate the operation of different converter controls. The results also demonstrate the converter's ability to black-start the island load and automatically transition the load current with varying loads in a few milliseconds. Furthermore, the power quality produced by the wave energy converter presents one of its significant challenges. Therefore, the performance of two distinct converter technologies was compared. The performance of the IGBT converter was evaluated against that of the SiC-based converter in terms of power quality. The study demonstrates that the use of SiC enhances power quality in all switching frequencies tested, achieving the most significant reduction of 78% in current THD and 92% in voltage THD at the 25 kHz switching frequency, thus validating its advantages for wave energy converter applications
Advances in posterity of visualization in paradigm of nano-level ultra-structures for nano-bio interaction studies
No full textThe progression in contemporary scientific field is facilitated by a multitude of sophisticated and cutting-edge methodologies that are employed for various research purposes. Among these methodologies, microscopy stands out as a fundamental and essential technique utilized in scientific investigations. Moreover, due to the continuous evolution and enhancement of microscopic methodologies, nanotechnology has reached a highly developed stage within modern scientific realm, particularly renowned for its wide-ranging applications in the fields of biomedicine and environmental science. When it comes to conducting comprehensive and in-depth experimental analyses to explore the nanotechnological aspects relevant to biological applications, the concept of nano-biological interaction emerges as the focal point of any research initiative. Nonetheless, this particular study necessitates a meticulous approach toward imaging and visualization at diverse magnification levels to ensure accurate observations and interpretations. It is widely acknowledged that modern microscopy has emerged as a sophisticated and invaluable instrument in this regard. This review aims to provide a comprehensive discussion on the progress made in microscopic techniques specifically tailored for visualizing the interactions between nanostructures and biological entities, thereby facilitating the exploration of the practical applications of nanotechnology in the realm of biological sciences
En intervjustudie om lärares uppfattningar av konkret material i algebra
No full textFlera forskningsstudier beskriver konkret material som ett viktigt hjälpmedel i undervisningen, inte minst vid komplexa operationer. Algebra är en stor del av det centrala innehållet i läroplanen och det är ett ämne som många menar har krupit ner i åldrarna. Vi har gjort en undersökning för att ta reda på lärares uppfattningar av användningen av konkret material i algebraundervisningen och syftet med studien var att ta reda på hur lärare använder sig av konkret material i undervisningen och vad som påverkar lärarnas val av metoder i algebra samt hur de kan förstår utifrån metoden CRA (concrete-representational-abstract). En kvalitativ metod valdes där sex utbildade lärare i årskurserna 1–3 har intervjuats. Samtliga intervjuer har analyserats utifrån en tematisk analys och resultatet visar på både likheter och skillnader i den forskning som uppsatsen bygger på. De intervjuade lärarna är överens om att konkret material har fler fördelar än nackdelar och att det är ett stort hjälpmedel i undervisningen av algebra
Var är kvinnorna? - en läromedelsanalys ur ett genusperspektiv
No full textSyftet med denna studie var att undersöka hur män respektive kvinnor framställs i läromedel för historieämnet i årskurs 1–3 i förhållande till de jämställdhetsuppdrag som skolan har enligt Skolverket och skollagen. Detta gjordes genom att undersöka frågeställningarna Hur representeras män/pojkar respektive kvinnor/flickor i läroboken? Hur många illustrationer visar kvinnor/flickor respektive män/pojkar i läroboken? Hur många gånger nämns kvinnor/flickor respektive män/pojkar i texten i läroboken? Datainsamlingen gjordes genom att analysera ett läromedel i SO riktat till årskurs 1–3. Analysen genomförs genom en kritisk diskursanalys samt en innehållsanalys. Resultatet av studien visade att kvinnorna har en undanskymd roll i historieskrivningen, både i texterna och i illustrationerna. Männen representeras som stora och starka medan kvinnorna skildras som små och svaga. Den undersökta läroboken reproducerar därför stereotypa traditionella könsnormer snarare än de jämställda könsnormer som uttrycks i skolans värdgrund och historieämnets kursplan
Följemeningar, genus och normer i läromedel på lågstadiet : En läromedelsanalys om följemeningar, genusrepresentation och normer i ABC-klubbens läseböcker
No full textThe overlooked trio : sleep duration, sampling time and physical exercise alter levels of olink-assessed blood biomarkers of cardiovascular risk.
No full textBiomarker profiling from biofluids such as blood are widely measured in clinical research, using for example Olink proteomics panels. One such research focus area is cardiovascular disease (CVD), for which chronic sleep restriction (SR) is a risk factor. However, it remains unclear whether blood levels of commonly measured CVD biomarkers are sensitive to acute dynamic factors such as SR, physical exercise (PEx), and time of day. In this crossover design, 16 normal-weight, healthy men underwent three highly standardized in-lab nights of SR (4.25 h/night) and normal sleep (NS, 8.5 h/night) in randomized order, with 88 CVD blood protein biomarkers quantified using the Olink technology (and selected validation using ELISA) in the morning, evening, and immediately before and repeatedly after 30 min of high-intensity exercise. We found significant time-of-day-dependent changes in several CVD biomarkers. Whereas several proteins were exercise-induced across sleep conditions (such as the canonical exerkines IL- 6 and BDNF), exercise-induced proteomic dynamics differed in response to recurrent SR, compared with following NS. Moreover, SR compared with NS resulted in a biomarker profile previously associated with increased prospective risk of several CVDs across large-scale cohorts (such as higher circulating levels of IL-27 and LGALS9). Our findings highlight how dynamic physiology can modulate CVD biomarker levels. These results also underscore the need to consider sleep duration as a key determinant of cardiovascular health-an emphasis reflected in recent American Heart Association guidelines. Further studies in women, older individuals, and patients with prior CVD, and across different chronotypes and dietary schedules are warranted
Adsorption and biological degradation of dissolved organic matter in terrestrial and aquatic ecosystems
No full textDissolved organic matter (DOM) is a complex mixture of organic compounds found across the biosphere. DOM concentration and composition are highly dynamic because of various transformation processes, such as microbial and photochemical degradation and adsorption to mineral particles. These processes are essential for carbon cycling across ecosystems and for water quality. Adsorption is important for DOM cycling, but its role in changing DOM composition and biological reactivity is rarely studied together. Extrinsic controls induced by water residence time can also impact DOM both spatially and temporally, yet these dynamics are poorly known. This thesis aims to fill these knowledge gaps in four studies. In the first study, DOM treatability and biodegradability across lake Mälaren in Sweden were investigated at six time points. The findings show that water residence time (WRT) plays a key role in shaping the composition of DOM. As WRT increases, DOM concentration and composition resist seasonality-driven temporal variations and gradually shift from terrestrial to aquatic origin, which enhances its treatability for drinking water. In the three following studies, batch experiments were sequentially performed to investigate adsorption controls on DOM composition and biodegradability across a range of mineral types and DOM sources from terrestrial and aquatic environments. The experiments (i) quantify adsorption capacities, (ii) evaluate DOM compositional changes due to adsorption using a multi-analytical approach incorporating fluorescence spectroscopy, mass spectrometry, and 1H NMR, and (iii) assess the biodegradability of the remaining DOM pool. The outcomes highlight that the adsorption capacity depends on the DOM sources, characteristics of mineral surfaces, and water chemistry. Strong adsorption interactions preferentially remove oxygen-rich, aromatic DOM, while weak interactions tend to target more diverse compounds. Moreover, DOM-mineral interactions have varying effects on biodegradability, ranging from strong to moderate and no enhancement after adsorption. The multi-analytical approach improves DOM characterization by reducing individual method biases. Notably, ¹H NMR effectively detects carbohydrate fractions, which are often overlooked by other methods. The thesis has important implications for descriptions of carbon dynamics in terrestrial and aquatic ecosystems, where agricultural, mining, and forestry increase mineral presence and enhance organo-mineral interactions
Extremely asymmetric bipolar magnetic field of the Bp star HD 57372
No full textFossil magnetic fields of early-type stars are typically characterised by symmetric or slightly distorted oblique dipolar surface geometries. Contrary to this trend, the late-B magnetic chemically peculiar star HD 57372 exhibits an unusually large rotational variation of its mean magnetic field modulus, suggesting a highly atypical field configuration. We present a Zeeman Doppler imaging analysis of HD 57372 that reveals an exceptionally asymmetric bipolar magnetic topology, which is rarely observed in early-type stars. According to our magnetic field maps, reconstructed from the intensity and circular polarisation profiles of Fe, Cr, and Ti lines, approximately 66% of the stellar surface is covered by a diffuse, outward directed radial field, with local field strength reaching 11.6 kG. The remaining 34% hosts a highly concentrated inward directed field with a strong horizontal component and a peak strength of 17.8 kG. These unusual surface magnetic field characteristics make HD 57372 a notable object for testing fossil-field theories and interpreting phase-resolved spectropolarimetric observations of early-type stars
Decrease of excessive daytime sleepiness after shunt treatment for normal pressure hydrocephalus
No full textSleepiness and apathy are often reported in patients with normal pressure hydrocephalus. However, research on outcomes after shunt surgery has mainly focused on the classical triad symptoms, that is, gait, cognition, and bladder dysfunction. This study aimed to describe the effects of shunt treatment on excessive daytime sleepiness and whether there was a relation to changes in ventricular volume. Pre- and postsurgical excessive daytime sleepiness was investigated using the Epworth sleepiness scale in a sample of 32 patients with normal pressure hydrocephalus who underwent shunt surgery. Data were gathered before surgery and at 1, 2, and 3 months after surgery and with different settings of the shunt. In the total sample, the Epworth sleepiness scale improved by a median of 1.5 points at 1 month after surgery, p = 0.026. The improvement was predominately found in the group (n = 6) with high presurgical daytime sleepiness (Epworth sleepiness scale >12) (median = 12 points, p = 0.035) compared with a median change of 0 points (p = 0.47) in the group with Epworth sleepiness scale <= 12 (n = 26). Between the postsurgical follow-ups, no further change in the Epworth sleepiness scale score was observed. The Epworth sleepiness scale score did not correlate with clinical tests nor with ventricular volume. Daytime sleepiness seems to be another domain of normal pressure hydrocephalus symptomatology in addition to the classical triad that is responsive to treatment, at least when pronounced. The Epworth sleepiness scale is a quick test to administer and could be a valuable addition to pre-surgical screening for treatable symptoms