| 1. |
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| 2. |
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| 3. |
- Lindh, Linnea, et al.
(författare)
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Dye-sensitized solar cells based on Fe N-heterocyclic carbene photosensitizers with improved rod-like push-pull functionality
- 2021
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 12:48, s. 16035-16053
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Tidskriftsartikel (refereegranskat)abstract
- A new generation of octahedral iron(ii)-N-heterocyclic carbene (NHC) complexes, employing different tridentate C^N^C ligands, has been designed and synthesized as earth-abundant photosensitizers for dye sensitized solar cells (DSSCs) and related solar energy conversion applications. This work introduces a linearly aligned push-pull design principle that reaches from the ligand having nitrogen-based electron donors, over the Fe(ii) centre, to the ligand having an electron withdrawing carboxylic acid anchor group. A combination of spectroscopy, electrochemistry, and quantum chemical calculations demonstrate the improved molecular excited state properties in terms of a broader absorption spectrum compared to the reference complex, as well as directional charge-transfer displacement of the lowest excited state towards the semiconductor substrate in accordance with the push-pull design. Prototype DSSCs based on one of the new Fe NHC photosensitizers demonstrate a power conversion efficiency exceeding 1% already for a basic DSSC set-up using only the I−/I3−redox mediator and standard operating conditions, outcompeting the corresponding DSSC based on the homoleptic reference complex. Transient photovoltage measurements confirmed that adding the co-sensitizer chenodeoxycholic acid helped in improving the efficiency by increasing the electron lifetime in TiO2. Time-resolved spectroscopy revealed spectral signatures for successful ultrafast (<100 fs) interfacial electron injection from the heteroleptic dyes to TiO2. However, an ultrafast recombination process results in undesirable fast charge recombination from TiO2back to the oxidized dye, leaving only 5-10% of the initially excited dyes available to contribute to a current in the DSSC. On slower timescales, time-resolved spectroscopy also found that the recombination dynamics (longer than 40 μs) were significantly slower than the regeneration of the oxidized dye by the redox mediator (6-8 μs). Therefore it is the ultrafast recombination down to fs-timescales, between the oxidized dye and the injected electron, that remains as one of the main bottlenecks to be targeted for achieving further improved solar energy conversion efficiencies in future work.
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| 4. |
- Lindh, Linnea, et al.
(författare)
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Multifaceted Deactivation Dynamics of Fe(II) N-Heterocyclic Carbene Photosensitizers
- 2023
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Ingår i: Journal of Physical Chemistry A. - 1089-5639. ; 127:48, s. 10210-10222
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Tidskriftsartikel (refereegranskat)abstract
- Excited state dynamics of three iron(II) carbene complexes that serve as prototype Earth-abundant photosensitizers were investigated by ultrafast optical spectroscopy. Significant differences in the dynamics between the investigated complexes down to femtosecond time scales are used to characterize fundamental differences in the depopulation of triplet metal-to-ligand charge-transfer (3MLCT) excited states in the presence of energetically accessible triplet metal-centered (3MC) states. Novel insights into the full deactivation cascades of the investigated complexes include evidence of the need to revise the deactivation model for a prominent iron carbene prototype complex, a refined understanding of complex 3MC dynamics, and a quantitative discrimination between activated and barrierless deactivation steps along the 3MLCT → 3MC → 1GS path. Overall, the study provides an improved understanding of photophysical limitations and opportunities for the use of iron(II)-based photosensitizers in photochemical applications.
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| 5. |
- Lindh, Linnea, et al.
(författare)
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Side-group switching between metal-to-ligand charge-transfer and metal-centered excited state properties in iron(II) N-heterocyclic carbene complexes
- 2024
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Ingår i: Coordination Chemistry Reviews. - 0010-8545. ; 506
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Forskningsöversikt (refereegranskat)abstract
- Fe(II) N-heterocyclic carbene (NHC) complexes have emerged over the last decade as a promising class of light-harvesting complexes for a variety of photochemical applications relying on the presence of high-energy excited states of mainly charge-transfer character with excited state lifetimes of tens of picoseconds or longer. Recent spectroscopic investigations have significantly refined the understanding of some of the key prototype complexes of this kind and highlighted the subtle balance between population of triplet metal-to-ligand charge-transfer (3MLCT) and triplet metal-centered (3MC) states as a key issue to better understand and ultimately control the excited state dynamics in these complexes. To present a broader perspective on this issue, we here re-examine and discuss the excited state properties of a series of complexes with different side-groups on a common Fe NHC scaffold. Both the steady-state absorption spectrum and excited state dynamics are influenced by the side-group substitution, and the changes are rationalized based on shifting of the lowest metal-to-ligand charge-transfer (MLCT) state in energy based on the electron-withdrawing or electron-donating properties of the side-groups. Only electron-withdrawing substituents such as carboxylic acid groups ensured that the majority excited population stays in the 3MLCT state for ∼20 ps rather than rapidly converting into metal-centered (MC) states. In other complexes, the 3MLCT state survived <300 fs after which the 3MC state was populated for ∼10 ps. The transient absorption results also show that the dynamics can be switched in a simple manner by deprotonating the carboxylic acid group, which renders some of the complexes pH-sensitive. For the here discussed complexes, the results from transient absorption measurements indicate that the 3MLCT and 3MC states were close enough in energy to enable the side-group to determine the photophysics. The emerging understanding of the 3MLCT-3MC balance, as well as the nature and properties of the 3MC state in these complexes with intermediate ligand field strength is used to provide a broader fundamental perspective required to improve the ligand-design of Fe carbene complexes for issues such as to ensure a long-lived 3MLCT state.
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| 6. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 7. |
- Alalam, Hanna, et al.
(författare)
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A High-Throughput Method for Screening for Genes Controlling Bacterial Conjugation of Antibiotic Resistance.
- 2020
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Ingår i: mSystems. - 2379-5077. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The rapid horizontal transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high-throughput. We then mix the resistance plasmid-carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals, and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within Escherichia coli populations, by screening the Keio deletion collection in high replication. We recover all seven known chromosomal gene mutants affecting conjugation as donors and identify many novel mutants, all of which diminish antibiotic resistance transmission. We validate nine of the novel genes' effects in liquid mating assays and complement one of the novel genes' effect on conjugation (rseA). The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improve the longevity of current and future antibiotics. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.IMPORTANCE The rapid transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within E. coli populations. We recover all previously known and many novel chromosomal gene mutants that affect conjugation efficiency. The new framework holds great potential for rapid screening of compounds that decrease transmission. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.
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| 8. |
- Andersson, Olov, 1979-, et al.
(författare)
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WARA-PS : a research arena for public safety demonstrations and autonomous collaborative rescue robotics experimentation
- 2021
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Ingår i: Autonomous Intelligent Systems. - : Springer Nature. - 2730-616X. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- A research arena (WARA-PS) for sensing, data fusion, user interaction, planning and control of collaborative autonomous aerial and surface vehicles in public safety applications is presented. The objective is to demonstrate scientific discoveries and to generate new directions for future research on autonomous systems for societal challenges. The enabler is a computational infrastructure with a core system architecture for industrial and academic collaboration. This includes a control and command system together with a framework for planning and executing tasks for unmanned surface vehicles and aerial vehicles. The motivating application for the demonstration is marine search and rescue operations. A state-of-art delegation framework for the mission planning together with three specific applications is also presented. The first one concerns model predictive control for cooperative rendezvous of autonomous unmanned aerial and surface vehicles. The second project is about learning to make safe real-time decisions under uncertainty for autonomous vehicles, and the third one is on robust terrain-aided navigation through sensor fusion and virtual reality tele-operation to support a GPS-free positioning system in marine environments. The research results have been experimentally evaluated and demonstrated to industry and public sector audiences at a marine test facility. It would be most difficult to do experiments on this large scale without the WARA-PS research arena. Furthermore, these demonstrator activities have resulted in effective research dissemination with high public visibility, business impact and new research collaborations between academia and industry.
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| 9. |
- Anjemark, Linnea, et al.
(författare)
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Car accidents in drivers with Parkinson's disease or multiple sclerosis: A Swedish nationwide study
- 2023
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 30:6, s. 1631-1638
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Parkinson's disease (PD) and multiple sclerosis (MS) can impair driving. However, we lack evidence on car accidents associated with these diseases. The aims of this study were to examine what types of car accident were associated with drivers with PD and MS, compared to individuals with ulcerative colitis (UC; the comparison group), and to evaluate the occurrence of car accidents in relation to years since diagnosis.Methods: This retrospective nationwide, registry-based study included drivers involved in car accidents between 2010 and 2019, based on the Swedish Traffic Accident Data Acquisition database. Data on pre-existing diagnoses were retrieved retrospectively from the National Patient Registry. Data analyses included group comparisons, time-to-event analysis, and binary logistic regression.Results: In total, 1491 drivers, including 199 with PD, 385 with MS, and 907 with UC, were registered to have been involved in a car accident. The mean time from diagnosis to the car accident was 5.6 years for PD, 8.0 years for MS, and 9.4 years for UC. Time to car accident since diagnosis differed significantly (p < 0.001) among groups (adjusted for age). Drivers with PD had more than twice the odds of a single-car accident than drivers with MS or UC, but no differences were observed between MS and UC.Conclusions: Drivers with PD were older and experienced the car accident within a shorter timeframe after disease diagnosis. Although several factors may cause a car accident, fitness to drive could be more thoroughly evaluated for patients with PD by physicians, even early after the diagnosis.
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| 10. |
- Bereza-Jarocinski, Robert, et al.
(författare)
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Distributed Model Predictive Control for Cooperative Landing
- 2020
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Ingår i: Proceedings 21st IFAC World Congress on Automatic Control - Meeting Societal Challenges. - : Elsevier BV. ; , s. 15180-15185
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Konferensbidrag (refereegranskat)abstract
- We design, implement and test two control algorithms for autonomously landing a drone on an autonomous boat. The first algorithm uses distributed model predictive control (DMPC), while the second combines a cascade controller with DMPC. The algorithms are implemented on a real drone, while the boat's motion is simulated, and their performance is compared to a centralized model predictive controller. Field experiments are performed, where all algorithms show an ability to land while avoiding violation of the safety constraints. The two distributed algorithms further show the ability to use longer prediction horizons than the centralized model predictive controller, especially in the cascade case, and also demonstrate improved robustness towards breaks in communication.
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| 11. |
- Björn, Linnea, 1994, et al.
(författare)
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Process-Induced Structures of Injection-Molded High-Density Polyethylene─Combining X-ray Scattering and Finite Element Modeling
- 2024
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Ingår i: ACS Applied Polymer Materials. - 2637-6105. ; 6:8, s. 4852-4864
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Tidskriftsartikel (refereegranskat)abstract
- The success of plastics heavily relies on fast melt processing methods used for large-scale industrial manufacturing, including injection molding. The hierarchical structure of the solid polymer depends on material selection combined with processing conditions, making mechanical properties of the injection molded part difficult to predict. Here we show how scanning small- and wide-angle X-ray scattering, birefringence microscopy, and polarized light optical microscopy can be combined with injection molding simulations to shed light on the correlation between the polymer morphology of high-density polyethylene and processing conditions. The scattering data revealed that the complex layered structure highly depends on the pressure during the holding phase of injection molding. Furthermore, we identified specific work of flow as a main parameter to capture the changes in morphology induced by varying the process settings. Overall, a good agreement was found between experimental data and the computational simulations, suggesting that computational simulations can be further used to predict the multiphase morphology of injection molded parts.
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| 12. |
- Björn, Linnea, 1994, et al.
(författare)
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Scanning Small-Angle X-ray Scattering of Injection-Molded Polymers: Anisotropic Structure and Mechanical Properties of Low-Density Polyethylene
- 2023
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Ingår i: ACS Applied Polymer Materials. - 2637-6105. ; 5:8, s. 6429-6440
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Tidskriftsartikel (refereegranskat)abstract
- Injection molding is known to create a layered anisotropicmorphologyacross the sample thickness due to varying shear and cooling ratesduring the manufacturing process. In this study, scanning small-angleX-ray scattering was used to visualize and quantify the distributionof hierarchical structures present in injection-molded parts of low-densitypolyethylene (LDPE) with varying viscosities. By combining scatteringdata with results from injection molding simulations and tensile testing,we find that oriented shish-kebab structures, as well as elongatedspherulite structures consisting of semicrystalline ellipsoids, contributeto high ultimate tensile strength along the flow direction. Furthermore,we show that a higher degree of orientation is found close to theinjection gate and in LDPE with higher viscosity, consequently fromelevated shear and cooling rates present during the injection moldingprocess.
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| 13. |
- Braam, Svenja, 1989, et al.
(författare)
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Exploring carbon source related localization and phosphorylation in the Snf1/Mig1 network using population and single cell-based a pproaches
- 2024
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Ingår i: MICROBIAL CELL. - 2311-2638. ; 11:1, s. 143-154
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Tidskriftsartikel (refereegranskat)abstract
- The AMPK/SNF1 pathway governs energy balance in eukaryotic cells, notably influencing glucose de-repression. In S. cerevisiae , Snf1 is phosphorylated and hence activated upon glucose depletion. This activation is required but is not sufficient for mediating glucose de-repression, indicating further glucosedependent regulation mechanisms. Employing fluorescence recovery after photobleaching (FRAP) in conjunction with non -linear mixed effects modelling, we explore the spatial dynamics of Snf1 as well as the relationship between Snf1 phosphorylation and its target Mig1 controlled by hexose sugars. Our results suggest that inactivation of Snf1 modulates Mig1 localization and that the kinetic of Snf1 localization to the nucleus is modulated by the presence of non -fermentable carbon sources. Our data offer insight into the true complexity of regulation of this central signaling pathway in orchestrating cellular responses to fluctuating environmental cues. These insights not only expand our understanding of glucose homeostasis but also pave the way for further studies evaluating the importance of Snf1 localization in relation to its phosphorylation state and regulation of downstream targets.
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| 14. |
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| 15. |
- Chábera, Pavel, et al.
(författare)
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Photofunctionality of iron(III) N-heterocyclic carbenes and related d5 transition metal complexes
- 2021
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Ingår i: Coordination Chemistry Reviews. - : Elsevier BV. - 0010-8545. ; 426
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Forskningsöversikt (refereegranskat)abstract
- Despite a few reports of photoluminescent and strongly photo-oxidizing transition metal complexes with a d5 electronic configuration, the photophysics and photochemistry of this class of transition metal complexes have largely remained unexplored. Recent investigations of earth-abundant iron(III) N-heterocyclic carbene (NHC) complexes have demonstrated promising photophysical and photochemical properties associated with low-spin (doublet) ligand-to-metal charge transfer (2LMCT) excitations, including nanosecond photoluminescence (PL) and capabilities to drive both photo-oxidation and photo-reduction reactions. These encouraging results are at first sight surprising in light of the general scarcity of known photofunctional complexes of any transition metal complexes with a d5 electronic configuration, including 1st, 2nd and 3rd row transition metal complexes of Mn(II), Tc(II), Re(II), Fe(III), Ru(III) and Os(III). Here, we review the photophysical and photochemical properties of the new Fe(III) NHC complexes together with related d5 transition metal complexes as a basis for a broader understanding of the unorthodox photophysical and photochemical properties associated with this open-shell electronic configuration. This includes considerations of the role of charge and spin effects on the ground state electronic structure, as well as discussions of charge transfer (CT) and metal centered (MC) excited state properties. The special properties of 2LMCT excited states are emphasized as a key feature to understand the photophysics of many photofunctional d5 transition metal complexes. Further aspects of excited state dynamics with d5 light-harvesting complexes, including both intra- and inter-molecular charge transfer processes, are also discussed. Finally, some fundamental challenges and emerging opportunities for further development of photofunctional Fe(III) NHC and related LMCT/d5 complexes for light-harvesting, light-emitting, and photo(electro)chemical applications are outlined. This includes some general considerations of how the specific photochemical properties of the LMCT/d5 complexes provides an exciting opportunity to develop a unique niche within the diversity of photofunctional molecular systems alongside other types of organic and inorganic chromophores commonly used in the field of molecular photochemistry.
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| 16. |
- Ekdahl, Linnea, et al.
(författare)
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A combination of second trimester oral metronidazole and no sexual intercourse during second and third trimester may reduce late miscarriage and premature delivery after fertility sparing radical trachelectomy
- 2021
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Ingår i: European Journal of Obstetrics and Gynecology and Reproductive Biology. - : Elsevier BV. - 0301-2115 .- 1872-7654. ; 265, s. 90-95
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Women with a previous trachelectomy have an increased risk of premature delivery and second trimester miscarriage. In this study we aim to evaluate factors and regimes possibly affecting the risk for prematurity following fertility sparing robotic radical trachelectomy (RRT) in cervical cancer. Methods: A retrospective study of the reproductive outcome following RRT with a cervical cerclage performed at one of four academic centers between 2007 and 2019. Factors possibly related to premature delivery, such as postoperative non-pregnant cervical length, previous vaginal deliveries, preservation of the uterine arteries, and the use of a second trimester oral metronidazole/no sexual intercourse regime, were assessed. Results: 109 women remained for analyses after excluding recurrences before pregnancy (n = 8), secondary hysterectomy (n = 2), and women with less than six months follow up (n = 10). 74 pregnancies occurred in 52/71 women attempting to conceive, 56 of which developed past the first trimester. Two of 22 women (9%) who were prescribed an oral metronidazole regime (400 mg × 2 from gestational week 15 + 0 to 21 + 6 and abstaining from sexual intercourse for the duration of the pregnancy) had a premature delivery, compared with 13/31 (42%) where the regime was not applied (p = 0.009). The association remained after regression analyses including possible contributing factors as of above, none of which associated with prematurity at regression analyses (p = 0.001). Conclusions: The observed four-fold reduction in premature delivery indicates that an oral metronidazole/no sexual intercourse regime may reduce second trimester miscarriage and premature deliveries following an RRT. No association was observed for other investigated factors.
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| 17. |
- Ekdahl, Linnea, et al.
(författare)
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Increased Institutional Surgical Experience in Robot-Assisted Radical Hysterectomy for Early Stage Cervical Cancer Reduces Recurrence Rate: Results from a Nationwide Study
- 2020
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Ingår i: JOURNAL OF CLINICAL MEDICINE. - : MDPI AG. - 2077-0383. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the impact of institutional surgical experience on recurrence following robotic radical hysterectomy (RRH) for early stage cervical cancer. All women in Sweden who underwent an RRH for stage IA2-IB1 cervical cancer at tertiary referral centers from its implementation in December 2005 until June 2017 were identified using a Swedish nationwide register and local hospital registers. Registry data were controlled by a chart review of all women. Recurrence rates and patterns of recurrence were compared between early and late (<= 50 vs. >50 procedures) institutional series. Six hundred and thirty-five women were included. Regression analysis identified a lower risk of recurrence with increased experience but without a clear cut off level. Among the 489 women who did not receive adjuvant radio chemotherapy (RC-T), the rate of recurrence was 3.6% in the experienced cohort (>50 procedures) compared to 9.3% in the introductory cohort (p < 0.05). This was also seen in tumors < 2 cm regardless of RC-T (p < 0.05), whereas no difference in recurrence was seen when analyzing all women receiving RC-T. In conclusion, the rate of recurrence following RRH for early stage cervical cancer decreased with increased institutional surgical experience, in tumors < 2 cm and in women who did not receive adjuvant RC-T.
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| 18. |
- Ekdahl, Linnea, et al.
(författare)
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Long term oncologic and reproductive outcomes after robot-assisted radical trachelectomy for early-stage cervical cancer. An international multicenter study
- 2022
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 164:3, s. 529-534
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Long term outcomes following fertility sparing robot-assisted radical trachelectomy (RRT). Methods: A retrospective study of consecutive women selected for RRT between 2007 and 2019 at five referral centres. Generally used selection criteria for fertility-sparing surgery were applied. Oncologic, reproductive and long-term clinical data were analysed. Results: Of the 166 included women, 149 completed a RRT. Median tumor size was 9 mm (range 3-20 mm), 111 women (75%) had FIGO 2009 stage IB1 cancer and 4.8% were node positive. At a median follow up of 58 months, 12 of all women (7.2%) and 9 of 149 women (6%) who underwent completed RRT with fertility preservation had recurred and two had died. 70 of 88 women (80%) who attempted to conceive succeeded, resulting in 81 pregnancies that progressed beyond the first trimester and 76 live births of which 54 (70%) were delivered at term and 65 (86%) delivered after gestational week 32. A short postoperative cervical length was associated with impaired fertility. A late secondary hysterectomy was necessary in four women due to persistent bleeding (n = 2), hematometra due to a cervical stenosis (n = 1) and recurrent dysplasia (n = 1). Conclusion: In this long-term follow-up of RRT the recurrence rate is comparable to larger individual studies of minimally invasive or vaginal radical trachelectomy with similar risk profile and follow up. The high pregnancy rate and low rate of premature delivery before 32 weeks GA may promote the use of robot-assisted approach.
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| 19. |
- Ekdahl, Linnea, et al.
(författare)
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Quality of life and long-term clinical outcome following robot-assisted radical trachelectomy
- 2021
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Ingår i: European Journal of Obstetrics and Gynecology and Reproductive Biology. - : Elsevier BV. - 0301-2115. ; 267, s. 234-240
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Tidskriftsartikel (refereegranskat)abstract
- Quality of Life and long-term clinical outcome following robot-assisted radical trachelectomy. Objectives: To evaluate quality of life (QoL) and long-term clinical outcome following robot-assisted radical trachelectomy (RRT). Study Design: Prospectively retrieved clinical data were rereviewed on all women planned for a fertility sparing RRT for early stage cervical cancer at Skåne University Hospital, Sweden between 2007 and 2020. QoL was assessed using the validated questionnaires EORTC QLQ-C30, QLQ-CX24 and the Swedish LYMQOL. Results: Data was analyzed from 49 women, 42 with a finalised RRT and seven with an aborted RRT due to nodal metastases (n = 3) or insufficient margins (n = 4). At a median follow-up time of 54 months one recurrence (2%) occurred (aborted RRT). According to QLQ-C30 the median global health status score was 75. The disease specific QLQ-C24 showed an impact on symptoms related to sexual function where sexual/vaginal functioning had a median score of 25 and 48% of patients reported worry that sex would cause physical pain. Despite this the functional items sexual activity and sexual enjoyment both had a median score of 66.7. Lymphoedema was reported in 45%, where 9% reported severe symptom with an impact on their QoL. No intraoperative complications and no postoperative complications ≥ Clavien Dindo grade III were observed. Twenty-two of 28 (79%) women who attempted to conceive were successful. A metronidazole/no intercourse regimen was applied between GW 15 + 0–21 + 6 in 26 of 28 pregnancies beyond first trimester resulting in a 92% term (≥GW 36 + 0) delivery rate. Conclusions: Although robot-assisted radical trachelectomy in this cohort was associated with a low recurrence rate, a high fertility rate and an exceptionally high term delivery rate, women's quality of life was affected postoperatively, particularly with regards to their sexual well-being and lymphatic side-effects.
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| 20. |
- Gustavsson Binder, Tobias, et al.
(författare)
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Hydrogen from biogas as fuel for buses in cold climate - Analysing the feasibility to produce hydrogen from local biogas and use in city buses in Luleå
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this study, we demonstrate that in certain cases, it can be advantageous to produce hydrogen from biogas and to use it in heavy-duty vehicles such as buses. In Luleå, it may be feasible to use hydrogen from biogas in city buses because there is a need for heating where waste heat from the fuel cell can be utilized. However, it is uncertain whether the waste heat is sufficient or if a separate auxiliary heater driven by diesel or HVO is needed. If such a heater is required, the conclusion is that hydrogen from biogas is suitable for other segments of heavy transportation, where battery electrification is not as suitable. Overall, our study shows that hydrogen from biogas may be interesting as a transitional fuel to increase the availability of environmentally friendly hydrogen until electrolyzer capacity is sufficiently expanded.At the same time, our mapping of the policy landscape concerning hydrogen and zero-emission buses shows that biohydrogen is disadvantaged in the EU's regulations on renewable hydrogen. This means that member states are restricted from providing support for investments to produce and distribute hydrogen from biogas and other biogenic feedstocks. The reason is that renewable hydrogen, according to EU terminology, is defined in the so-called delegated act on renewable fuels of non-biological origin (RFNBO). It is established that renewable hydrogen should be based on non-biological feedstocks (i.e., from electrolysis) and must meet a number of criteria.The results are interesting in the context of urban bus traffic rapidly moving towards zero-emission operation. In Sweden and many other countries, battery buses have become a common and obvious feature on city streets. But just like for other segments of heavy-duty vehicles, another technology to achieve zero-emission operation has also received increased attention, namely hydrogen and fuel cell buses. In Sweden, only a few fuel cell buses have been used - and moreover, only on a trial basis - but in several European cities, they have already begun to be used on a significant scale. An advantage of fuel cell operation with hydrogen from biogas is that it allows for the continued utilization of the biogas already produced and purchased for existing city bus traffic.System study consisting of two partsWe arrived at the result by investigating the suitability of both producing hydrogen from biogas at the existing sewage treatment plant in Luleå and the feasibility for LLT to use fuel cell buses in its city bus traffic. The study has considered both costs associated with each part and climate impact from a life cycle perspective for fuel production and bus operation.
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| 21. |
- Gustavsson, Emil, 1987, et al.
(författare)
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Modulation of Structural Heterogeneity Controls Phytochrome Photoswitching
- 2020
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Ingår i: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 118:2, s. 415-421
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes sense red/far-red light and control many biological processes in plants, fungi, and bacteria. Although the crystal structures of dark- and light-adapted states have been determined, the molecular mechanisms underlying photoactivation remain elusive. Here, we demonstrate that the conserved tongue region of the PHY domain of a 57-kDa photosensory module of Deinococcus radiodurans phytochrome changes from a structurally heterogeneous dark state to an ordered, light-activated state. The results were obtained in solution by utilizing a laser-triggered activation approach detected on the atomic level with high-resolution protein NMR spectroscopy. The data suggest that photosignaling of phytochromes relies on careful modulation of structural heterogeneity of the PHY tongue.
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| 22. |
- Isaksson, Linnéa, et al.
(författare)
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Signaling Mechanism of Phytochromes in Solution.
- 2021
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Ingår i: Structure. - : Elsevier BV. - 1878-4186 .- 0969-2126. ; 29:2, s. 151-160
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Tidskriftsartikel (refereegranskat)abstract
- Phytochrome proteins guide the red/far-red photoresponse of plants, fungi, and bacteria. Crystal structures suggest that the mechanism of signal transduction from the chromophore to the output domains involves refolding of the so-called PHY tongue. It is currently not clear how the two other notable structural features of the phytochrome superfamily, the so-called helical spine and a knot in the peptide chain, are involved in photoconversion. Here, we present solution NMR data of the complete photosensory core module from Deinococcus radiodurans. Photoswitching between the resting and the active states induces changes in amide chemical shifts, residual dipolar couplings, and relaxation dynamics. All observables indicate a photoinduced structural change in the knot region and lower part of the helical spine. This implies that a conformational signal is transduced from the chromophore to the helical spine through the PAS and GAF domains. The discovered pathway underpins functional studies of plant phytochromes and may explain photosensing by phytochromes under biological conditions.
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| 23. |
- Kaufhold, Simon, et al.
(författare)
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Microsecond Photoluminescence and Photoreactivity of a Metal-Centered Excited State in a Hexacarbene-Co(III) Complex
- 2021
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; , s. 1307-1312
-
Tidskriftsartikel (refereegranskat)abstract
- The photofunctionality of the cobalt-hexacarbene complex [Co(III)(PhB(MeIm)3)2]+ (PhB(MeIm)3 = tris(3-methylimidazolin-2-ylidene)(phenyl)borate) has been investigated by time-resolved optical spectroscopy. The complex displays a weak (φ ∼10-4) but remarkably long-lived (τ ∼1 μs) orange photoluminescence at 690 nm in solution at room temperature following excitation with wavelengths shorter than 350 nm. The strongly red-shifted emission is assigned from the spectroscopic evidence and quantum chemical calculations as a rare case of luminescence from a metal-centered state in a 3d6 complex. Singlet oxygen quenching supports the assignment of the emitting state as a triplet metal-centered state and underlines its capability of driving excitation energy transfer processes.
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| 24. |
- Lapandic, Dzenan, et al.
(författare)
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Aperiodic Communication for MPC in Autonomous Cooperative Landing
- 2021
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Ingår i: IFAC PAPERSONLINE. - : Elsevier BV. - 2405-8963. ; , s. 113-118
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the rendezvous problem for the autonomous cooperative landing of an unmanned aerial vehicle (UAV) on an unmanned surface vehicle (USV). Such heterogeneous agents, with nonlinear dynamics, are dynamically decoupled but share a common cooperative rendezvous task. The underlying control scheme is based on distributed Model Predictive Control (MPC). The main contribution is a rendezvous algorithm with an online update rule of the rendezvous location. The algorithm only requires the agents to exchange information when they can not guarantee to rendezvous. Hence, the exchange of information occurs aperiodically, which reduces the necessary communication between the agents. Furthermore, we prove that the algorithm guarantees recursive feasibility. The simulation results illustrate the effectiveness of the proposed algorithm applied to the problem of autonomous cooperative landing.
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| 25. |
- Lindh, Linnea, et al.
(författare)
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Photophysics and photochemistry of iron carbene complexes for solar energy conversion and photocatalysis
- 2020
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Ingår i: Catalysts. - : MDPI AG. - 2073-4344. ; 10:3
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Forskningsöversikt (refereegranskat)abstract
- Earth-abundant first row transition metal complexes are important for the development of large-scale photocatalytic and solar energy conversion applications. Coordination compounds based on iron are especially interesting, as iron is the most common transition metal element in the Earth’s crust. Unfortunately, iron-polypyridyl and related traditional iron-based complexes generally suffer from poor excited state properties, including short excited-state lifetimes, that make them unsuitable for most light-driven applications. Iron carbene complexes have emerged in the last decade as a new class of coordination compounds with significantly improved photophysical and photochemical properties, that make them attractive candidates for a range of light-driven applications. Specific aspects of the photophysics and photochemistry of these iron carbenes discussed here include long-lived excited state lifetimes of charge transfer excited states, capabilities to act as photosensitizers in solar energy conversion applications like dye-sensitized solar cells, as well as recent demonstrations of promising progress towards driving photoredox and photocatalytic processes. Complementary advances towards photofunctional systems with both Fe(II) complexes featuring metal-to-ligand charge transfer excited states, and Fe(III) complexes displaying ligand-to-metal charge transfer excited states are discussed. Finally, we outline emerging opportunities to utilize the improved photochemical properties of iron carbenes and related complexes for photovoltaic, photoelectrochemical and photocatalytic applications.
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| 26. |
- Lührs, Oscar, et al.
(författare)
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Resection of the upper paracervical lymphovascular tissue should be an integral part of a pelvic sentinel lymph node algorithm in early stage cervical cancer
- 2021
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 0090-8258. ; 163:2, s. 289-293
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the prevalence of lymph nodes and lymph node metastases (LNMs) in the upper paracervical lymphovascular tissue (UPLT) in early stage cervical cancer. Methods: In this prospective study consecutive women with stage IA1-IB1 cervical cancer underwent a pelvic lymphadenectomy including identification of sentinel nodes (SLNs) as part of a nodal staging procedure in conjunction with a robotic radical hysterectomy (RRH) or robotic radical trachelectomy (RRT). Indocyanine green (ICG) was used as tracer. The UPLT was separately removed and defined as “SLN-parametrium” and, as all SLN tissue, subjected to ultrastaging and immunohistochemistry. Primary endpoint was prevalence of lymph nodes and metastatic lymph nodes in the UPLT. Secondary endpoints were complications associated with removal of the UPLT. Results: One hundred and forty-five women were analysed. Nineteen (13.1%) had pelvic LNMs, all identified by at least one metastatic SLN. In 76 women (52.4%) at least one UPLT lymph node was identified. Metastatic UPLT lymph nodes were identified in six women of which in three women (2.1% of all women and 15.8% of node positive women) without lateral pelvic LNMs. Thirteen women had lateral pelvic SLN LNMs with either no (n = 5) or benign (n = 8) UPLT lymph nodes. No intraoperative complications occurred due to the removal of the UPLT. Conclusion: Removal of the UPLT should be an integral part of the SLN concept in early stage cervical cancer.
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| 27. |
- Lührs, Oscar, et al.
(författare)
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Similar distribution of pelvic sentinel lymph nodes and nodal metastases in cervical and endometrial cancer. A prospective study based on lymphatic anatomy
- 2022
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 0090-8258. ; 165:3, s. 466-471
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Comparing the anatomical distribution of metastatic and non-metastatic pelvic sentinel lymph nodes (SLN) in cervical and endometrial cancer. Methods: Detailed SLN mapping results were prospectively retrieved in cervical (n = 145) or high-risk endometrial cancer (n = 201) patients undergoing a robotic staging procedure. Cervically injected Indocyanine Green (ICG), allowing for reinjection in case of inadequate mapping, was used as tracer. An anatomically based definition of SLNs was adhered to evaluating the upper (UPP) and lower (LPP) paracervical lymphatic pathways. The positions of SLNs were intraoperatively depicted on an anatomical chart. A completory pelvic lymphadenectomy was performed. Mapping rates and anatomical distribution of SLNs and the location of pelvic nodal metastases were compared between groups. Results: The bilateral mapping rate was 97.9% and 95.0% for cervical and endometrial cancer respectively (p = .16). The proportion of typically positioned (interiliac and proximal obturator fossa) SLNs along the UPP was similar between groups (78.1% vs 82.1%, p = .09), and the rate of metastatic SLNs in the obturator fossa was 54.1% and 48.6% respectively (p = .45). All pelvic node positive women (cervical cancer n = 19, endometrial cancer n = 37) had at least one metastatic SLN. Anatomically typical positions could not be defined along the LPP. Conclusion: The anatomical location of SLNs and SLN metastases are similar in cervical and endometrial cancer suggesting that sensitivity results for an SLN concept in endometrial cancer and cervical cancer can be accumulated.
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| 28. |
- Nissling, Linnea, 1991, et al.
(författare)
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Effects of patient-driven iCBT for anxiety in routine primary care and the relation between increased experience of empowerment and outcome : A randomized controlled trial
- 2021
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Ingår i: Internet Interventions. - : Elsevier. - 2214-7829. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Background: The World Health Organization has declared that primary care should be organized to empower individuals, families, and communities to optimize health. Internet cognitive behavioral therapy (iCBT) tailored by psychologists' initial assessments to meet patients' specific needs have shown promising effects. However, few studies have evaluated patient involvement in decisions during iCBT. Aim: This study aimed to explore the effect of patient-driven iCBT compared to standard iCBT on perceived control over treatment, adherence, and level of anxiety symptoms. A secondary aim was to assess the relationship between changes in empowerment and changes in anxiety symptoms. Method: Participants were patients recruited form primary care and assessed as meeting the criterion for an anxiety disorder. Participants were randomized to patient-driven iCBT (n = 27) or standard iCBT (n = 28). Patient-driven iCBT was adapted to participants' preferences regarding for example focus of treatment program and order of modules. Participants randomized to the control condition received the standard iCBT program for anxiety disorders at the participating unit. The outcome measures were patients' perceived control over treatment, adherence to treatment, symptoms of anxiety, depression and general disability as well as the experience of empowerment. Results: Participants in patient-driven iCBT had statistically higher perceived control over treatment (t(43) = 2.13, p = .04). Symptoms were significantly reduced in both arms with regards to anxiety, depression, and general disability. A significant time per condition interaction effect for anxiety symptoms was observed (df = 45.0; F = 3.055; p = .038), where the patient-driven condition had a significantly larger reduction in anxiety. For both groups a significant correlation of r = 0.47 was found between changes in empowerment and changes in anxiety. Conclusion: Results indicate that iCBT that is patient-driven, may have a greater effect on anxiety, than standard iCBT. The effect on perceived control over treatment might also be larger in patient-driven treatments than in standard iCBT. Internet-based therapies inherently promote as active agents of their own care and might be well suited for promoting perceived control and empowerment. Findings need to be replicated given the small sample size and the explorative nature of the study.
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| 29. |
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| 30. |
- Persson, Jan, et al.
(författare)
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A prospective study evaluating an optimized sentinel node algorithm in early stage cervical cancer : The PROSACC-study
- 2024
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Ingår i: Gynecologic Oncology. - 0090-8258. ; 187, s. 178-183
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Tidskriftsartikel (refereegranskat)abstract
- Objective: A single center prospective non-randomized study to assess a systematically developed anatomically-based sentinel lymph node (SLN) algorithm in cervical cancer. Methods: Consecutive women with FIGO 2009 stage 1A2-2A1 cervical cancer undergoing robotic radical hysterectomy/trachelectomy between September 2014 and January 2023 had cervically injected Indocyanine Green (ICG) as a tracer for detection of pelvic SLN. An anatomically based surgical algorithm was adhered to; defining SLNs as the juxtauterine mapped nodes within the upper and lower paracervical lymphatic pathways including separate removal of the parauterine lymphovascular tissue (PULT). A completion pelvic lymphadenectomy was performed. Ultrastaging and immunohistochemistry was performed on SLNs, including the PULT. Results: 181 women were included for analysis. Median histologic tumor size was 14.0 mm (range 2–80 mm). The bilateral mapping rate was 98.3%. As per protocol an interim analysis rejected H0 and inclusion stopped at 29 node positive women, all identified by at least one metastatic ICG-defined SLN. One woman awaiting histology at study-closure was node positive and included in the analysis. Sensitivity was 100% (95% CI, 88.4%–100%) and NPV 100% (95% CI, 97.6%–100%). In node positive women, the proximal obturator position harbored 46.1% of all SLN metastases representing the only position in 40% and 10% had isolated metastases in the PULT. Conclusions: Strictly adhering to an anatomically based SLN-algorithm including identification of parallell lymphatics within major pathways, partilularly the obturator compartment, assessment of the PULT, restricting nodal dissection to the removal of SLNs accurately identifies pelvic nodal metastatic disease in early-stage cervical cancer.
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| 31. |
- Persson, Linnea, et al.
(författare)
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An optimization algorithm based on forward recursion with applications to variable horizon MPC
- 2024
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Ingår i: European Journal of Control. - : ELSEVIER. - 0947-3580 .- 1435-5671. ; 75
-
Tidskriftsartikel (refereegranskat)abstract
- We consider optimization algorithms designed for variable horizon model predictive control. Traditionally, such problems are considered intractable for real-time applications that require fast computations, as they need to solve multiple optimal control problems with varying horizons at each sampling instance. The main contribution is an algorithm that efficiently solves multiple optimal control problems with different prediction horizons in a recursive manner. This algorithm has been successfully implemented and integrated into the OSQP solver, resulting in a real-time controller that is both fast and reliable. To assess the effectiveness of the approach, we conducted evaluations in both a realistic simulation environment and on real hardware during outdoor flight experiments. Specifically, we focused on two distinct rendezvous maneuvers for autonomous landings of unmanned aerial vehicles. The results obtained from these evaluations further validate the practicality and efficacy of the proposed algorithm. (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of European Control Association. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
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| 32. |
- Persson, Linnea, 1992-
(författare)
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Model Predictive Control for Cooperative Rendezvous of Autonomous Unmanned Vehicles
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates cooperative maneuvers for aerial vehicles autonomously landing on moving platforms. The objective has been to develop methods for safely performing such landings on real systems subject to a variety of disturbances, as well as physical and computational constraints. Two specific examples are considered: the landing of a fixed-wing drone on top of a moving ground carriage; and the landing of a quadcopter on the deck of a boat. The maneuvers are executed in a cooperative manner where both vehicles are allowed to take actions to reach their common objective, while avoiding safety based spatial constraints. Applications of such systems can be found in, for example, autonomous deliveries, emergency landings, and in search and rescue missions. Particular challenges of cooperative landing maneuvers include the heterogeneous and nonlinear dynamics, the coupled control, the sensitivity to disturbances, and the safety criticality of performing a high-velocity landing maneuver.In this thesis, a cooperative landing algorithm based on Model Predictive Control (MPC) that includes spatial safety constraints for avoiding dangerous regions is developed. MPC offers many advantages for the autonomous landing problem, with its ability to explicitly consider dynamic equations, constraints, and disturbances directly in the computation of the control inputs. It is shown that the cooperative landing MPC can be decoupled into a horizontal and a vertical sub-problem. This result makes the optimization problems significantly less computationally demandingand facilitates the real-time implementation. The autonomous landing maneuver is further improved by the employment of a variable horizon. The variable-horizon MPC framework lets the finite horizon length become a part of the optimization problem, and makes it possible to always extend the horizon to the end of the landing maneuver. An algorithm for variable horizon MPC that can be implemented to real-time systems is derived by the use of efficient update rules, and by taking into account the similarities between the multiple optimization problems that we have to solve in each sampling period. The algorithm is fast enough to be used even in time-critical systems with long horizons. Furthermore, the solution time of the variable-horizon MPC decreases as the target gets closer. This means that the computational demand becomes smaller in the most critical part of the landing maneuver.The algorithms are derived for two different landing systems, and are subsequently implemented in realistic simulations and in real-world outdoors flight tests through the WASP research arena. The results demonstrate both that the controllers are practically implementable on real systems with computational limitations, and that the suggested controller can successfully be used to perform the cooperative landing under the influence of external disturbances and under the constraint of various safety requirements.
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| 33. |
- Persson, Linnea, 1992-, et al.
(författare)
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Variable Prediction Horizon Control for Cooperative Landing on Moving Target
- 2021
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Ingår i: 2021 IEEE Aerospace Conference (AEROCONF 2021). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- Motivated by applications in autonomous UAV landings on moving platforms, this paper proposes a Variable Horizon Model Predictive Control (VH-MPC) algorithm for cooperative rendezvous problems. Compared to existing VH-MPC, for which the associated computations are extensive which makes implementation on real-time UAV-platform systems most difficult, the look-ahead horizon in our VH-MPC algorithm adapts to the distance and time left to reach the rendezvous state in a computationally tractable manner. Our main contribution is the derivation of these efficient horizon-update rules. More specifically, the computational concerns in standard MPC for rendezvous maneuvers stem from that for the MPC to find a feasible solution, the look-ahead time needs to be long enough to ensure that a complete trajectory to the target set exists (i.e., the position and point in time where the two agents should meet). However, choosing a too long horizon results in expensive computations. A variable horizon can be used to find a horizon that is just long enough to make the control problem feasible, while reducing the computational complexity as the target set gets closer. To validate our proposed VH-MPC scheme, we conduct several experiments both in a realistic simulation environment (FlightGear-JSBSim, which includes nonlinear and complex dynamical effects), and in outdoors experiments with a quadrotor. Our experiments demonstrate i) the prohibitive computational cost of standard MPC, and ii) successful real-time computations of feasible trajectories and control inputs for an autonomous cooperative landing (fixed-wing UAV landing on an unmanned sea-surface vehicle), while satisfying important spatial safety-constraints (e.g., zones around the landing platform to avoid). Our experiments establish the feasibility of important future real-world applications in, e.g., sea rescue missions with fixed-wing drones and autonomous sea vessels.
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| 34. |
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| 35. |
- Persson, Sebastian, 1996, et al.
(författare)
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Modelling of glucose repression signalling in yeast Saccharomyces cerevisiae
- 2022
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Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1356 .- 1567-1364. ; 22:1
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Forskningsöversikt (refereegranskat)abstract
- Saccharomyces cerevisiae has a sophisticated signalling system that plays a crucial role in cellular adaptation to changing environments. The SNF1 pathway regulates energy homeostasis upon glucose derepression; hence, it plays an important role in various processes, such as metabolism, cell cycle and autophagy. To unravel its behaviour, SNF1 signalling has been extensively studied. However, the pathway components are strongly interconnected and inconstant; therefore, elucidating its dynamic behaviour based on experimental data only is challenging. To tackle this complexity, systems biology approaches have been successfully employed. This review summarizes the progress, advantages and disadvantages of the available mathematical modelling frameworks covering Boolean, dynamic kinetic, single-cell models, which have been used to study processes and phenomena ranging from crosstalks to sources of cell-to-cell variability in the context of SNF1 signalling. Based on the lessons from existing models, we further discuss how to develop a consensus dynamic mechanistic model of the entire SNF1 pathway that can provide novel insights into the dynamics of nutrient signalling.
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| 36. |
- Prakash, Om, et al.
(författare)
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Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)-NHC Complexes with Long-Lived 2LMCT Excited States
- 2022
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 61:44, s. 17515-17526
-
Tidskriftsartikel (refereegranskat)abstract
- Fe(III) complexes with N-heterocyclic carbene (NHC) ligands belong to the rare examples of Earth-abundant transition metal complexes with long-lived luminescent charge-transfer excited states that enable applications as photosensitizers for charge separation reactions. We report three new hexa-NHC complexes of this class: [Fe(brphtmeimb)2]PF6 (brphtmeimb = [(4-bromophenyl)tris(3-methylimidazol-2-ylidene)borate]–, [Fe(meophtmeimb)2]PF6 (meophtmeimb = [(4-methoxyphenyl)tris(3-methylimidazol-2-ylidene)borate]–, and [Fe(coohphtmeimb)2]PF6 (coohphtmeimb = [(4-carboxyphenyl)tris(3-methylimidazol-2-ylidene)borate]–. These were derived from the parent complex [Fe(phtmeimb)2]PF6 (phtmeimb = [phenyltris(3-methylimidazol-2-ylidene)borate]– by modification with electron-withdrawing and electron-donating substituents, respectively, at the 4-phenyl position of the ligand framework. All three Fe(III) hexa-NHC complexes were characterized by NMR spectroscopy, high-resolution mass spectroscopy, elemental analysis, single crystal X-ray diffraction analysis, electrochemistry, Mößbauer spectroscopy, electronic spectroscopy, magnetic susceptibility measurements, and quantum chemical calculations. Their ligand-to-metal charge-transfer (2LMCT) excited states feature nanosecond lifetimes (1.6–1.7 ns) and sizable emission quantum yields (1.7–1.9%) through spin-allowed transition to the doublet ground state (2GS), completely in line with the parent complex [Fe(phtmeimb)2]PF6 (2.0 ns and 2.1%). The integrity of the favorable excited state characteristics upon substitution of the ligand framework demonstrates the robustness of the scorpionate motif that tolerates modifications in the 4-phenyl position for applications such as the attachment in molecular or hybrid assemblies.
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| 37. |
- Prakash, Om, et al.
(författare)
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Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C∧N∧C) Pincer Ligand─A Comparative Study
- 2024
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 63:6, s. 2909-2918
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Tidskriftsartikel (refereegranskat)abstract
- We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1′-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.
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| 38. |
- Rosemann, Nils W., et al.
(författare)
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Competing dynamics of intramolecular deactivation and bimolecular charge transfer processes in luminescent Fe(iii) N-heterocyclic carbene complexes
- 2023
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 14:13, s. 3569-3579
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Tidskriftsartikel (refereegranskat)abstract
- Steady state and ultrafast spectroscopy on [FeIII(phtmeimb)2]PF6 (phtmeimb = phenyl(tris(3-methylimidazol-2-ylidene))borate) was performed over a broad range of temperatures. The intramolecular deactivation dynamics of the luminescent doublet ligand-to-metal charge-transfer (2LMCT) state was established based on Arrhenius analysis, indicating the direct deactivation of the 2LMCT state to the doublet ground state as a key limitation to the lifetime. In selected solvent environments photoinduced disproportionation generating short-lived Fe(iv) and Fe(ii) complex pairs that subsequently undergo bimolecular recombination was observed. The forward charge separation process is found to be temperature-independent with a rate of ∼1 ps−1. Subsequent charge recombination takes place in the inverted Marcus region with an effective barrier of 60 meV (483 cm−1). Overall, the photoinduced intermolecular charge separation efficiently outcompetes the intramolecular deactivation over a broad range of temperatures, highlighting the potential of [FeIII(phtmeimb)2]PF6 to perform photocatalytic bimolecular reactions.
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| 39. |
- Rusek, Linnéa, et al.
(författare)
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Lifetime risk of stroke in the general male population
- 2020
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 142:1, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Most previous studies of incidence rates of stroke are from register studies, while data from prospective cohort studies are limited. The aim of the present study was to describe hazard rates, prevalence and cumulative proportion free from stroke during a lifelong follow-up of a representative sample of middle-aged men sampled from the general population. Methods A population-based sample of 855 men, all born in 1913, was investigated at 50 years of age and followed up with repeated medical examinations at age 54, 60, 67, 75 and 80. Data from hospital records and the Cause of Death Register were collected, and all stroke events during 48 years of follow-up were registered. Medical records were scrutinized in order to confirm and validate the stroke diagnoses. Results One man was excluded because of stroke prior to baseline, while 176 of the remaining 854 men (20.7%) suffered a first-ever stroke during follow-up. The total 5-year stroke risk (hazard rate) increased with age, from 3.54 (95% CI: 0-7.55) per 1000 persons at risk at age 50 years, to 119.05 (95% CI: 45.39-192.70) at age 90 years. The stroke prevalence peaked at age 80 and older, with about 120 cases per 1000 years of observation. The survival rate (cumulative proportion free from stroke) at age 98 was 50.0%. Conclusion One out of five men in this population sample suffered a stroke of any type during follow-up from 50 to 98 years of age and the cumulative incidence was close to 50%.
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| 40. |
- Selegård, Linnéa, et al.
(författare)
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In-situ growth of cerium nanoparticles for chrome-free, corrosion resistant anodic coatings
- 2021
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 410
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Tidskriftsartikel (refereegranskat)abstract
- Chrome-based anodization and sealing combined is a cost-effective solution for developing good corrosion protective coatings on aluminum (Al) and its alloys. The toxicity of hexavalent chromium, however, requires new, sustainable, environmentally friendly, and efficient chromate-free sealing procedures. Herein, a combination of cerium (Ce) sealing and hydrothermal sealing (HTS) is employed to improve the corrosion resistance of the commonly used alloy AA2024-T3 anodized by tartaric sulfuric acid (TSA). The morphologies and components of the resulting surfaces are systematically studied. Characterization technologies such as SEM, TEM, EDX, XRD, and XPS demonstrate the in-situ growth of Ce oxide nanoparticles all through the porous structures of the anodic coating and closing of the pores by additional HTS treatment. The results from the standardized corrosion test (ASTM B895) demonstrate an improved corrosion resistance obtained by the utilized chrome-free process.
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| 41. |
- Thomsen, Hanna, 1989, et al.
(författare)
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Increased antibiotic efficacy and noninvasive monitoring of Staphylococcus epidermidis biofilms using per-cysteamine-substituted γ-cyclodextrin - A delivery effect validated by fluorescence microscopy.
- 2020
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Ingår i: International journal of pharmaceutics. - : Elsevier BV. - 1873-3476 .- 0378-5173. ; 587
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Tidskriftsartikel (refereegranskat)abstract
- Limited and poor delivery of antibiotics is cited as one reason for the difficulty in treating antibiotic-resistant biofilms associated with chronic infections. We investigate the effectiveness of a positively charged, single isomer cyclodextrin derivative, octakis[6-(2-aminoethylthio)-6-deoxy]-γ-CD (γCys) to improve the delivery of antibiotics to biofilms. Using multiphoton laser scanning microscopy complemented with super-resolution fluorescence microscopy, we showed that γCys tagged with fluorescein (FITC) is uniformly distributed throughout live S. epidermidis biofilm cultures in vitro and results suggest it is localized extracellularly in the biofilm matrix. NMR spectroscopic data in aqueous solution confirm that γCys forms inclusion complexes with both the antibiotics oxacillin and rifampicin. Efficacy of γCys/antibiotic (oxacillin and rifampicin) was measured in the biofilms. While treatment with γCys/oxacillin had little improvement over oxacillin alone, γCys/rifampicin reduced the biofilm viability to background levels demonstrating a remarkable improvement over rifampicin alone. The strong synergistic effect for γCys/rifampicin is at this stage not clearly understood, but plausible explanations are related to increased solubility of rifampicin upon complexation and/or synergistic interference with components of the biofilm. The results demonstrate that designed cyclodextrin nanocarriers, like γCys, efficiently deliver suitable antibiotics to biofilms and that fluorescence microscopy offers a novel approach for mechanistic investigations.
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| 42. |
- Tingö, Lina, 1984-, et al.
(författare)
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The effect of whole-diet interventions on memory and cognitive function in healthy older adults : a systematic review
- 2024
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Ingår i: Advances in nutrition (Bethesda, Md.). - : Oxford University Press. - 2161-8313 .- 2156-5376.
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: An increasing number of cross-sectional studies suggests that diet may impact memory and cognition in healthy older adults. However, randomized, controlled trials investigating the effects of whole-diet interventions on memory and cognition in healthy older adults are rather rare and conflicting results are often reported.OBJECTIVE: Therefore, a systematic review was conducted to compile the current evidence regarding the potential effects of whole-diet interventions on 1) memory and, 2) other cognitive outcomes in older adults.METHODS: Studies that reported on randomized, controlled trials with dietary interventions in healthy older adults (60 yrs. and older) were included. Studies utilizing supplements, single food items or trials in specific patient groups (ie neurodegenerative diagnoses) were excluded.RESULTS: For the 23 included articles, the main outcomes examined fell into one or more of the following categories: cognitive task-based outcomes related to memory, other cognitive task-based outcomes, and additional outcomes related to cognitive function or disease risk. Three of the studies that investigated dietary interventions alone and two multi-domain study showed positive effects on memory function, whereas five multi-domain interventions and one intervention that focused on diet alone showed positive effects on other cognitive outcomes.CONCLUSIONS: The effect of randomized, controlled whole-diet interventions on memory and cognitive function in healthy older adults is modest and inconclusive, highlighting the need for more well-designed, sufficiently powered studies. Furthermore, the potential mechanisms by which diet impacts cognition in healthy aging need to be elucidated.REGISTRY AND REGISTRY NUMBER FOR SYSTEMATIC REVIEWS OR META-ANALYSES: This systematic review is registered in PROSPERO under ID CRD42022329759.
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| 43. |
- Wenzel, H. H. B., et al.
(författare)
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A federated approach to identify women with early-stage cervical cancer at low risk of lymph node metastases
- 2023
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 185, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Lymph node metastases (pN+) in presumed early-stage cervical cancer negatively impact prognosis. Using federated learning, we aimed to develop a tool to identify a group of women at low risk of pN+, to guide the shared decision-making process concerning the extent of lymph node dissection.Methods: Women with cervical cancer between 2005 and 2020 were identified retrospectively from population-based registries: the Danish Gynaecological Cancer Database, Swedish Quality Registry for Gynaecologic Cancer and Netherlands Cancer Registry. Inclusion cri-teria were: squamous cell carcinoma, adenocarcinoma or adenosquamous carcinoma; The International Federation of Gynecology and Obstetrics 2009 IA2, IB1 and IIA1; treatment with radical hysterectomy and pelvic lymph node assessment. We applied privacy-preserving federated logistic regression to identify risk factors of pN+. Significant factors were used to stratify the risk of pN+. Results: We included 3606 women (pN+ 11%). The most important risk factors of pN+ were lymphovascular space invasion (LVSI) (odds ratio [OR] 5.16, 95% confidence interval [CI], 4.59-5.79), tumour size 21-40 mm (OR 2.14, 95% CI, 1.89-2.43) and depth of invasion > 10 mm (OR 1.81, 95% CI, 1.59-2.08). A group of 1469 women (41%)-with tumours without LVSI, tumour size 520 mm, and depth of invasion 510 mm-had a very low risk of pN + (2.4%, 95% CI, 1.7-3.3%). Conclusion: Early-stage cervical cancer without LVSI, a tumour size 520 mm and depth of invasion 510 mm, confers a low risk of pN+. Based on an international privacy-preserving analysis, we developed a useful tool to guide the shared decision-making process regarding lymph node dissection.& COPY; 2023 Elsevier Ltd. All rights reserved.
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