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1. Anatomically and mechanically conforming patient-specific spinal fusion cages designed by full-scale topology optimization

Author

Smit, Thijs, Aage, Niels, Haschtmann, Daniel, Ferguson, Stephen J., and Helgason, Benedikt

Subjects
Physics - Medical Physics
Abstract

Cage subsidence after instrumented lumbar spinal fusion surgery remains a significant cause of treatment failure, specifically for posterior or transforaminal lumbar interbody fusion. Recent advancements in computational techniques and additive manufacturing, have enabled the development of patient-specific implants and implant optimization to specific functional targets. This study aimed to introduce a novel full-scale topology optimization formulation that takes the structural response of the adjacent bone structures into account in the optimization process. The formulation includes maximum and minimum principal strain constraints that lower strain concentrations in the adjacent vertebrae. This optimization approach resulted in anatomically and mechanically conforming spinal fusion cages. Subsidence risk was quantified in a commercial finite element solver for off-the-shelf, anatomically conforming and the optimized cages, in two representative patients. We demonstrated that the anatomically and mechanically conforming cages reduced subsidence risk by 91% compared to an off-the-shelf implant with the same footprint for a patient with normal bone quality and 54% for a patient with osteopenia. Prototypes of the optimized cage were additively manufactured and mechanically tested to evaluate the manufacturability and integrity of the design and to validate the finite element model., Comment: 34 pages, 8 figures

Published
2024

2. Understanding the genetic complexity of puberty timing across the allele frequency spectrum.

Author

Kentistou, Katherine, Kaisinger, Lena, Stankovic, Stasa, Vaudel, Marc, Mendes de Oliveira, Edson, Messina, Andrea, Walters, Robin, Liu, Xiaoxi, Busch, Alexander, Helgason, Hannes, Thompson, Deborah, Santoni, Federico, Petricek, Konstantin, Zouaghi, Yassine, Huang-Doran, Isabel, Gudbjartsson, Daniel, Bratland, Eirik, Lin, Kuang, Gardner, Eugene, Zhao, Yajie, Jia, Raina, Terao, Chikashi, Riggan, Marjorie, Bolla, Manjeet, Yazdanpanah, Mojgan, Yazdanpanah, Nahid, Bradfield, Jonathan, Broer, Linda, Campbell, Archie, Chasman, Daniel, Cousminer, Diana, Franceschini, Nora, Franke, Lude, Girotto, Giorgia, He, Chunyan, Järvelin, Marjo-Riitta, Joshi, Peter, Kamatani, Yoichiro, Karlsson, Robert, Luan, Jianan, Lunetta, Kathryn, Mägi, Reedik, Mangino, Massimo, Medland, Sarah, Meisinger, Christa, Noordam, Raymond, Nutile, Teresa, Concas, Maria, Polašek, Ozren, Porcu, Eleonora, Ring, Susan, Sala, Cinzia, Smith, Albert, Tanaka, Toshiko, van der Most, Peter, Vitart, Veronique, Wang, Carol, Willemsen, Gonneke, Zygmunt, Marek, Ahearn, Thomas, Andrulis, Irene, Anton-Culver, Hoda, Antoniou, Antonis, Auer, Paul, Barnes, Catriona, Beckmann, Matthias, Berrington de Gonzalez, Amy, Bogdanova, Natalia, Bojesen, Stig, Brenner, Hermann, Buring, Julie, Canzian, Federico, Chang-Claude, Jenny, Couch, Fergus, Cox, Angela, Crisponi, Laura, Czene, Kamila, Daly, Mary, Demerath, Ellen, Dennis, Joe, Devilee, Peter, De Vivo, Immaculata, Dörk, Thilo, Dunning, Alison, Dwek, Miriam, Eriksson, Johan, Fasching, Peter, Fernandez-Rhodes, Lindsay, Ferreli, Liana, Fletcher, Olivia, Gago-Dominguez, Manuela, García-Closas, Montserrat, García-Sáenz, José, González-Neira, Anna, Grallert, Harald, Guénel, Pascal, Haiman, Christopher, Hall, Per, Hamann, Ute, and Hakonarson, Hakon

Subjects
Humans, Female, Menarche, Puberty, Gene Frequency, Animals, Multifactorial Inheritance, Mice, Genome-Wide Association Study, Adolescent, Puberty, Precocious, Polymorphism, Single Nucleotide, Receptors, G-Protein-Coupled, Puberty, Delayed, Child
Abstract

Pubertal timing varies considerably and is associated with later health outcomes. We performed multi-ancestry genetic analyses on ~800,000 women, identifying 1,080 signals for age at menarche. Collectively, these explained 11% of trait variance in an independent sample. Women at the top and bottom 1% of polygenic risk exhibited ~11 and ~14-fold higher risks of delayed and precocious puberty, respectively. We identified several genes harboring rare loss-of-function variants in ~200,000 women, including variants in ZNF483, which abolished the impact of polygenic risk. Variant-to-gene mapping approaches and mouse gonadotropin-releasing hormone neuron RNA sequencing implicated 665 genes, including an uncharacterized G-protein-coupled receptor, GPR83, which amplified the signaling of MC3R, a key nutritional sensor. Shared signals with menopause timing at genes involved in DNA damage response suggest that the ovarian reserve might signal centrally to trigger puberty. We also highlight body size-dependent and independent mechanisms that potentially link reproductive timing to later life disease.

Published
2024

4. The correlation between CpG methylation and gene expression is driven by sequence variants

Author

Stefansson, Olafur Andri, Sigurpalsdottir, Brynja Dogg, Rognvaldsson, Solvi, Halldorsson, Gisli Hreinn, Juliusson, Kristinn, Sveinbjornsson, Gardar, Gunnarsson, Bjarni, Beyter, Doruk, Jonsson, Hakon, Gudjonsson, Sigurjon Axel, Olafsdottir, Thorunn Asta, Saevarsdottir, Saedis, Magnusson, Magnus Karl, Lund, Sigrun Helga, Tragante, Vinicius, Oddsson, Asmundur, Hardarson, Marteinn Thor, Eggertsson, Hannes Petur, Gudmundsson, Reynir L., Sverrisson, Sverrir, Frigge, Michael L., Zink, Florian, Holm, Hilma, Stefansson, Hreinn, Rafnar, Thorunn, Jonsdottir, Ingileif, Sulem, Patrick, Helgason, Agnar, Gudbjartsson, Daniel F., Halldorsson, Bjarni V., Thorsteinsdottir, Unnur, and Stefansson, Kari

Published
2024
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7. Self-injection-locked optical parametric oscillator based on microcombs

Author

Lei, Fuchuan, Sun, Yi, Helgason, Óskar B., Ye, Zhichao, Gao, Yan, Karlsson, Magnus, Andrekson, Peter A, and Torres-Company, Victor

Subjects
Physics - Optics
Abstract

Narrow-linewidth yet tunable laser oscillators are one of the most important tools for precision metrology, optical atomic clocks, sensing and quantum computing. Commonly used tunable coherent oscillators are based on stimulated emission or stimulated Brillouin scattering; as a result, the operating wavelength band is limited by the gain media. Based on nonlinear optical gain, optical parametric oscillators (OPOs) enable coherent signal generation within the whole transparency window of the medium used. However, the demonstration of OPO-based Hertz-level linewidth and tunable oscillators has remained elusive. Here, we present a tunable coherent oscillator based on a multimode coherent OPO in a high-Q microresonator, i.e., a microcomb. Single-mode coherent oscillation is realized through self-injection locking (SIL) of one selected comb line. We achieve coarse tuning up to 20 nm, and an intrinsic linewidth down to sub-Hertz level, which is three orders of magnitude lower than the pump. Furthermore, we demonstrate that this scheme results into repetition rate stabilization of the microcomb. These results open exciting possibilities for generating tunable coherent radiation where stimulated emission materials are difficult to obtain, and the stabilization of microcomb sources beyond the limits imposed by the thermorefractive noise in the cavity.

Published
2023
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8. Superefficient microcombs at the wafer level

Author

Girardi, Marcello, Helgason, Óskar B., Ortega, Carmen H. López, Rebolledo-Salgado, Israel, and Torres-Company, Victor

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

Photonic integrated circuits utilize planar waveguides to process light on a chip, encompassing functions like generation, routing, modulation, and detection. Similar to the advancements in the electronics industry, photonics research is steadily transferring an expanding repertoire of functionalities onto integrated platforms. The combination of best-in-class materials at the wafer-level increases versatility and performance, suitable for large-scale markets, such as datacentre interconnects, lidar for autonomous driving or consumer health. These applications require mature integration platforms to sustain the production of millions of devices per year and provide efficient solutions in terms of power consumption and wavelength multiplicity for scalability. Chip-scale frequency combs offer massive wavelength parallelization, holding a transformative potential in photonic system integration, but efficient solutions have only been reported at the die level. Here, we demonstrate a silicon nitride technology on a 100 mm wafer that aids the performance requirements of soliton microcombs in terms of yield, spectral stability, and power efficiency. Soliton microcombs are reported with an average conversion efficiency exceeding 50%, featuring 100 lines at 100 GHz repetition rate. We further illustrate the enabling possibilities of the space multiplicity, i.e., the large wafer-level redundancy, for establishing new sensing applications, and show tri-comb interferometry for broadband phase-sensitive spectroscopy. Combined with heterogeneous integration of lasers, we envision a proliferation of high-performance photonic systems for applications in future navigation systems, data centre interconnects, and ranging.

Published
2023

9. Sequence variants associated with BMI affect disease risk through BMI itself

Author

Gudmundur Einarsson, Gudmar Thorleifsson, Valgerdur Steinthorsdottir, Florian Zink, Hannes Helgason, Thorhildur Olafsdottir, Solvi Rognvaldsson, Vinicius Tragante, Magnus O. Ulfarsson, Gardar Sveinbjornsson, Audunn S. Snaebjarnarson, Hafsteinn Einarsson, Hildur M. Aegisdottir, Gudrun A. Jonsdottir, Anna Helgadottir, Solveig Gretarsdottir, Unnur Styrkarsdottir, Hannes K. Arnason, Ragnar Bjarnason, Emil Sigurdsson, David O. Arnar, Einar S. Bjornsson, Runolfur Palsson, Gyda Bjornsdottir, Hreinn Stefansson, Thorgeir Thorgeirsson, Patrick Sulem, Unnur Thorsteinsdottir, Hilma Holm, Daniel F. Gudbjartsson, and Kari Stefansson

Subjects
Science
Abstract

Abstract Mendelian Randomization studies indicate that BMI contributes to various diseases, but it’s unclear if this is entirely mediated by BMI itself. This study examines whether disease risk from BMI-associated sequence variants is mediated through BMI or other mechanisms, using data from Iceland and the UK Biobank. The associations of BMI genetic risk score with diseases like fatty liver disease, knee replacement, and glucose intolerance were fully attenuated when conditioned on BMI, and largely for type 2 diabetes, heart failure, myocardial infarction, atrial fibrillation, and hip replacement. Similar attenuation was observed for chronic kidney disease and stroke, though results varied. Findings were consistent across sexes, except for myocardial infarction. Residual effects may result from temporal BMI changes, pleiotropy, measurement error, non-linear relationships, non-collapsibility, or confounding. The attenuation extent of BMI genetic risk score on disease associations suggests the potential impact of reducing BMI on disease risk.

Published
2024
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10. Sequence variants associated with BMI affect disease risk through BMI itself

Author

Einarsson, Gudmundur, Thorleifsson, Gudmar, Steinthorsdottir, Valgerdur, Zink, Florian, Helgason, Hannes, Olafsdottir, Thorhildur, Rognvaldsson, Solvi, Tragante, Vinicius, Ulfarsson, Magnus O., Sveinbjornsson, Gardar, Snaebjarnarson, Audunn S., Einarsson, Hafsteinn, Aegisdottir, Hildur M., Jonsdottir, Gudrun A., Helgadottir, Anna, Gretarsdottir, Solveig, Styrkarsdottir, Unnur, Arnason, Hannes K., Bjarnason, Ragnar, Sigurdsson, Emil, Arnar, David O., Bjornsson, Einar S., Palsson, Runolfur, Bjornsdottir, Gyda, Stefansson, Hreinn, Thorgeirsson, Thorgeir, Sulem, Patrick, Thorsteinsdottir, Unnur, Holm, Hilma, Gudbjartsson, Daniel F., and Stefansson, Kari

Published
2024
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12. Loss-of-function variants in ITSN1 confer high risk of Parkinson’s disease

Author

Skuladottir, Astros Th., Tragante, Vinicius, Sveinbjornsson, Gardar, Helgason, Hannes, Sturluson, Arni, Bjornsdottir, Anna, Jonsson, Palmi, Palmadottir, Vala, Sveinsson, Olafur A., Jensson, Brynjar O., Gudjonsson, Sigurjon A., Ivarsdottir, Erna V., Gisladottir, Rosa S., Gunnarsson, Arni F., Walters, G. Bragi, Jonsdottir, Gudrun A., Thorgeirsson, Thorgeir E., Bjornsdottir, Gyda, Holm, Hilma, Gudbjartsson, Daniel F., Sulem, Patrick, Stefansson, Hreinn, and Stefansson, Kari

Published
2024
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14. Leukaemia exposure alters the transcriptional profile and function of BCR::ABL1 negative macrophages in the bone marrow niche

Author

Dawson, Amy, Zarou, Martha M., Prasad, Bodhayan, Bittencourt-Silvestre, Joana, Zerbst, Désirée, Himonas, Ekaterini, Hsieh, Ya-Ching, van Loon, Isabel, Blanco, Giovanny Rodriguez, Ianniciello, Angela, Kerekes, Zsombor, Krishnan, Vaidehi, Agarwal, Puneet, Almasoudi, Hassan, McCluskey, Laura, Hopcroft, Lisa E. M., Scott, Mary T., Baquero, Pablo, Dunn, Karen, Vetrie, David, Copland, Mhairi, Bhatia, Ravi, Coffelt, Seth B., Tiong, Ong Sin, Wheadon, Helen, Zanivan, Sara, Kirschner, Kristina, and Helgason, G. Vignir

Published
2024
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16. Axiomatic Design of an automatic card dealing robot

Author

Sigmarsson Anton Björn, Helgason Ágúst Benóný, Albertsson Óskar Ágúst, and Foley Joseph Timothy

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

When you’re playing card games with friends, a problem often occurs, at some point, no one wants to be the dealer. We propose an automatic card dealing robot. There are a few products on the market today that are expensive or missing critical functionality to fulfill the role of a card dealer. Our product will be more affordable and more portable than existing systems. The robot can be used in a variety of applications, for education, for the physically challenged, and of course for fun. The goal was to build a robot using Axiomatic Design methodology, with faster card dealing capabilities than a human.

Published
2019
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17. Loss-of-function variants in ITSN1 confer high risk of Parkinson’s disease

Author

Astros Th. Skuladottir, Vinicius Tragante, Gardar Sveinbjornsson, Hannes Helgason, Arni Sturluson, Anna Bjornsdottir, Palmi Jonsson, Vala Palmadottir, Olafur A. Sveinsson, Brynjar O. Jensson, Sigurjon A. Gudjonsson, Erna V. Ivarsdottir, Rosa S. Gisladottir, Arni F. Gunnarsson, G. Bragi Walters, Gudrun A. Jonsdottir, Thorgeir E. Thorgeirsson, Gyda Bjornsdottir, Hilma Holm, Daniel F. Gudbjartsson, Patrick Sulem, Hreinn Stefansson, and Kari Stefansson

Subjects
Neurology. Diseases of the nervous system, RC346-429
Abstract

Abstract Parkinson’s disease (PD) is a debilitating neurodegenerative disorder and its rising global incidence highlights the need for the identification of modifiable risk factors. In a gene-based burden test of rare variants (8647 PD cases and 777,693 controls) we discovered a novel association between loss-of-function variants in ITSN1 and PD. This association was further supported with burden data from the Neurodegenerative Disease Knowledge Portal and the Accelerating Medicines Partnership Parkinson’s Disease Knowledge Platform. Our findings show that Rho GTPases and disruptions in synaptic vesicle transport may be involved in the pathogenesis of PD, pointing to the possibility of novel therapeutic approaches.

Published
2024
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18. Morphological changes of the south-eastern wall of Askja caldera, Iceland over the past 80 years

Author

Alina V. Shevchenko, Thomas R. Walter, Magnus T. Gudmundsson, Joaquín M. C. Belart, Pouria Marzban, Edgar U. Zorn, Þorsteinn Sæmundsson, Jón Kristinn Helgason, Jens M. Turowski, Magdalena S. Vassileva, Mahdi Motagh, and Daniel Müller

Subjects
Geology, QE1-996.5, Environmental sciences, GE1-350
Abstract

Abstract Calderas are subcircular depressions with near-vertical walls, which are often gravitationally unstable and prone to mass movements that sequentially widen their basins. However, the details of these erosional changes are difficult to decipher due to short observational periods. Here, we use a photogrammetric dataset of nearly 80 years to study the landslide-prone south-eastern wall of Askja caldera (Iceland). We analyzed aerial data from 1945 and 1987, stereo satellite data from 2013 and 2022, and drone images acquired in 2019, 2022, and 2023. We developed an inventory of geomorphological features and identified types of slope instability. We describe over 700 features, including circa 500 fractures, 200 sinkholes, and four major landslides. We found that morphological changes were persistent over the observation period, accumulating in a sector that collapsed in 2014. We discuss various factors of slope instability at Askja including possible volcano-permafrost interaction, and other processes that could induce mass wasting.

Published
2024
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19. Measuring prairie snow water equivalent with combined UAV-borne gamma spectrometry and lidar

Author

P. Harder, W. D. Helgason, and J. W. Pomeroy

Subjects
Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract

Despite decades of effort, there remains an inability to measure snow water equivalent (SWE) at high spatial resolutions using remote sensing. Passive gamma ray spectrometry is one of the only well-established methods to reliably remotely sense SWE, but airborne applications to date have been limited to observing kilometre-scale areal averages. Noting the increasing capabilities of unoccupied aerial vehicles (UAVs) and miniaturization of passive gamma ray spectrometers, this study tested the ability of a UAV-borne gamma spectrometer and concomitant UAV-borne lidar to quantify the spatial variability of SWE at high spatial resolutions. Gamma and lidar observations from a UAV (UAV-gamma and UAV-lidar) were collected over two seasons from shallow, wind-blown, prairie snowpacks in Saskatchewan, Canada, with validation data collected from manual snow depth and density observations. A fine-resolution (0.25 m) reference dataset of SWE, to test UAV-gamma methods, was developed from UAV-lidar snow depth and snow survey snow density observations. The ability of UAV-gamma to resolve the areal average and spatial variability of SWE was promising with appropriate flight characteristics. Survey flights flown at a velocity of 5 m s−1, altitude of 15 m, and line spacing of 15 m were unable to capture the average or spatial variability of SWE within the uncertainty of the reference dataset. Slower, lower, and denser flight lines at a velocity of 4 m s−1, altitude of 8 m, and line spacing of 8 m were able to successfully observe areal average SWE and its variability at spatial resolutions greater than 22.5 m. Using a combination of UAV-based gamma SWE and UAV-based lidar snow depth improved the spatial representation of SWE substantially and permitted estimation of SWE at a spatial resolution 0.25 m with a ± 14.3 mm error relative to the reference SWE dataset. UAV-borne gamma spectrometry to estimate SWE is a promising and novel technique that has the potential to improve the measurement of shallow prairie snowpacks, and when combined with UAV-borne lidar snow depths, can provide fine-resolution, high-accuracy estimates of prairie SWE. Research on optimal hardware, data processing, and interpolation techniques is called for to further improve this remote sensing product and explore its application in other environments.

Published
2024
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20. LamaH-Ice: LArge-SaMple DAta for Hydrology and Environmental Sciences for Iceland

Author

H. B. Helgason and B. Nijssen

Subjects
Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract

Access to mountainous regions for monitoring streamflow, snow and glaciers is often difficult, and many rivers are thus not gauged and hydrological measurements are limited. Consequently, cold-region watersheds, particularly heavily glacierized ones, are poorly represented in large-sample hydrology (LSH) datasets. We present a new LSH dataset for Iceland, termed LamaH-Ice (LArge-SaMple DAta for Hydrology and Environmental Sciences for Iceland). Glaciers and ice caps cover about 10 % of Iceland and, while streamflow has been measured for several decades, these measurements have not previously been published in a consistent manner. The dataset provides daily and hourly hydrometeorological time series and catchment characteristics for 107 river basins in Iceland, covering an area of almost 46 000 km2 (45 % of Iceland's area), with catchment sizes ranging from 4 to 7500 km2. LamaH-Ice conforms to the structure of existing LSH datasets and includes most variables contained in these datasets as well as additional information relevant to cold-region hydrology, e.g., time series of snow cover, glacier mass balance and albedo. LamaH-Ice also includes dynamic catchment characteristics to account for changes in land cover, vegetation and glacier extent. A large majority of the watersheds in LamaH-Ice are not subject to human activities, such as diversions and flow regulations. Streamflow measurements under natural flow conditions are highly valuable to hydrologists seeking to model and comprehend the natural hydrological cycle or estimate climate change trends. The LamaH-Ice dataset (Helgason and Nijssen, 2024) is intended for the research community to improve the understanding of hydrology in cold-region environments. LamaH-Ice is publicly available on HydroShare at https://doi.org/10.4211/hs.86117a5f36cc4b7c90a5d54e18161c91 (Helgason and Nijssen, 2024).

Published
2024
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21. Global assessment of marine plastic exposure risk for oceanic birds.

Author

Clark, Bethany, Carneiro, Ana, Pearmain, Elizabeth, Rouyer, Marie-Morgane, Clay, Thomas, Cowger, Win, Phillips, Richard, Manica, Andrea, Hazin, Carolina, Eriksen, Marcus, González-Solís, Jacob, Adams, Josh, Albores-Barajas, Yuri, Alfaro-Shigueto, Joanna, Alho, Maria, Araujo, Deusa, Arcos, José, Arnould, John, Barbosa, Nadito, Barbraud, Christophe, Beard, Annalea, Beck, Jessie, Bell, Elizabeth, Bennet, Della, Berlincourt, Maud, Biscoito, Manuel, Bjørnstad, Oskar, Bolton, Mark, Booth Jones, Katherine, Borg, John, Bourgeois, Karen, Bretagnolle, Vincent, Bried, Joël, Briskie, James, Brooke, M, Brownlie, Katherine, Bugoni, Leandro, Calabrese, Licia, Campioni, Letizia, Carey, Mark, Carle, Ryan, Carlile, Nicholas, Carreiro, Ana, Catry, Paulo, Catry, Teresa, Cecere, Jacopo, Ceia, Filipe, Cherel, Yves, Choi, Chang-Yong, Cianchetti-Benedetti, Marco, Clarke, Rohan, Cleeland, Jaimie, Colodro, Valentina, Congdon, Bradley, Danielsen, Jóhannis, De Pascalis, Federico, Deakin, Zoe, Dehnhard, Nina, DellOmo, Giacomo, Delord, Karine, Descamps, Sébastien, Dilley, Ben, Dinis, Herculano, Dubos, Jerome, Dunphy, Brendon, Emmerson, Louise, Fagundes, Ana, Fayet, Annette, Felis, Jonathan, Fischer, Johannes, Freeman, Amanda, Fromant, Aymeric, Gaibani, Giorgia, García, David, Gjerdrum, Carina, Gomes, Ivandra, Forero, Manuela, Granadeiro, José, Grecian, W, Grémillet, David, Guilford, Tim, Hallgrimsson, Gunnar, Halpin, Luke, Hansen, Erpur, Hedd, April, Helberg, Morten, Helgason, Halfdan, Henry, Leeann, Hereward, Hannah, Hernandez-Montero, Marcos, Hindell, Mark, Hodum, Peter, Imperio, Simona, Jaeger, Audrey, Jessopp, Mark, Jodice, Patrick, Jones, Carl, Jones, Christopher, Jónsson, Jón, and Kane, Adam

Subjects
Animals, Plastics, Waste Products, Environmental Monitoring, Oceans and Seas, Birds, Indian Ocean
Abstract

Plastic pollution is distributed patchily around the worlds oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Published
2023

22. Segmentation methods for quantifying X-ray Computed Tomography based biomarkers to assess hip fracture risk: a systematic literature review

Author

Cristina Falcinelli, Vee San Cheong, Lotta Maria Ellingsen, and Benedikt Helgason

Subjects
segmentation, finite element modeling, hip fracture risk, computed tomography, osteoporosis, CT-derived biomarkers, Biotechnology, TP248.13-248.65
Abstract

BackgroundThe success of using bone mineral density and/or FRAX to predict femoral osteoporotic fracture risk is modest since they do not account for mechanical determinants that affect bone fracture risk. Computed Tomography (CT)-based geometric, densitometric, and finite element-derived biomarkers have been developed and used as parameters for assessing fracture risk. However, to quantify these biomarkers, segmentation of CT data is needed. Doing this manually or semi-automatically is labor-intensive, preventing the adoption of these biomarkers into clinical practice. In recent years, fully automated methods for segmenting CT data have started to emerge. Quantifying the accuracy, robustness, reproducibility, and repeatability of these segmentation tools is of major importance for research and the potential translation of CT-based biomarkers into clinical practice.MethodsA comprehensive literature search was performed in PubMed up to the end of July 2024. Only segmentation methods that were quantitatively validated on human femurs and/or pelvises and on both clinical and non-clinical CT were included. The accuracy, robustness, reproducibility, and repeatability of these segmentation methods were investigated, reporting quantitatively the metrics used to evaluate these aspects of segmentation. The studies included were evaluated for the risk of, and sources of bias, that may affect the results reported.FindingsA total of 54 studies fulfilled the inclusion criteria. The analysis of the included papers showed that automatic segmentation methods led to accurate results, however, there may exist a need to standardize reporting of accuracy across studies. Few works investigated robustness to allow for detailed conclusions on this aspect. Finally, it seems that the bone segmentation field has only addressed the concept of reproducibility and repeatability to a very limited extent, which entails that most of the studies are at high risk of bias.InterpretationBased on the studies analyzed, some recommendations for future studies are made for advancing the development of a standardized segmentation protocol. Moreover, standardized metrics are proposed to evaluate accuracy, robustness, reproducibility, and repeatability of segmentation methods, to ease comparison between different approaches.

Published
2024
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23. In silico medical device testing of anatomically and mechanically conforming patient-specific spinal fusion cages designed by full-scale topology optimisation

Author

Thijs Smit, Niels Aage, Daniel Haschtmann, Stephen J. Ferguson, and Benedikt Helgason

Subjects
in silico, ASME V&V40, model credibility, medical device testing, topology optimisation, patient-specific, Biotechnology, TP248.13-248.65
Abstract

A full-scale topology optimisation formulation has been developed to automate the design of cages used in instrumented transforaminal lumbar interbody fusion. The method incorporates the mechanical response of the adjacent bone structures in the optimisation process, yielding patient-specific spinal fusion cages that both anatomically and mechanically conform to the patient, effectively mitigating subsidence risk compared to generic, off-the-shelf cages and patient-specific devices. In this study, in silico medical device testing on a cohort of seven patients was performed to investigate the effectiveness of the anatomically and mechanically conforming devices using titanium and PEEK implant materials. A median reduction in the subsidence risk by 89% for titanium and 94% for PEEK implant materials was demonstrated compared to an off-the-shelf implant. A median reduction of 75% was achieved for a PEEK implant material compared to an anatomically conforming implant. A credibility assessment of the computational model used to predict the subsidence risk was provided according to the ASME V&V40–2018 standard.

Published
2024
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25. Author Correction: Large-scale plasma proteomics comparisons through genetics and disease associations

Author

Eldjarn, Grimur Hjorleifsson, Ferkingstad, Egil, Lund, Sigrun H., Helgason, Hannes, Magnusson, Olafur Th., Gunnarsdottir, Kristbjorg, Olafsdottir, Thorunn A., Halldorsson, Bjarni V., Olason, Pall I., Zink, Florian, Gudjonsson, Sigurjon A., Sveinbjornsson, Gardar, Magnusson, Magnus I., Helgason, Agnar, Oddsson, Asmundur, Halldorsson, Gisli H., Magnusson, Magnus K., Saevarsdottir, Saedis, Eiriksdottir, Thjodbjorg, Masson, Gisli, Stefansson, Hreinn, Jonsdottir, Ingileif, Holm, Hilma, Rafnar, Thorunn, Melsted, Pall, Saemundsdottir, Jona, Norddahl, Gudmundur L., Thorleifsson, Gudmar, Ulfarsson, Magnus O., Gudbjartsson, Daniel F., Thorsteinsdottir, Unnur, Sulem, Patrick, and Stefansson, Kari

Published
2024
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26. A population-based survey of FBN1 variants in Iceland reveals underdiagnosis of Marfan syndrome

Author

Klemenzdottir, Elin Ola, Arnadottir, Gudny Anna, Jensson, Brynjar Orn, Jonasdottir, Adalbjorg, Katrinardottir, Hildigunnur, Fridriksdottir, Run, Jonasdottir, Aslaug, Sigurdsson, Asgeir, Gudjonsson, Sigurjon Axel, Jonsson, Jon Johannes, Stefansdottir, Vigdis, Danielsen, Ragnar, Palsdottir, Astridur, Jonsson, Hakon, Helgason, Agnar, Magnusson, Olafur Thor, Thorsteinsdottir, Unnur, Bjornsson, Hans Tomas, Stefansson, Kari, and Sulem, Patrick

Published
2024
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27. Publisher Correction: Understanding the genetic complexity of puberty timing across the allele frequency spectrum

Author

Kentistou, Katherine A., Kaisinger, Lena R., Stankovic, Stasa, Vaudel, Marc, Mendes de Oliveira, Edson, Messina, Andrea, Walters, Robin G., Liu, Xiaoxi, Busch, Alexander S., Helgason, Hannes, Thompson, Deborah J., Santoni, Federico, Petricek, Konstantin M., Zouaghi, Yassine, Huang-Doran, Isabel, Gudbjartsson, Daniel F., Bratland, Eirik, Lin, Kuang, Gardner, Eugene J., Zhao, Yajie, Jia, Raina Y., Terao, Chikashi, Riggan, Marjorie J., Bolla, Manjeet K., Yazdanpanah, Mojgan, Yazdanpanah, Nahid, Bradfield, Jonathan P., Broer, Linda, Campbell, Archie, Chasman, Daniel I., Cousminer, Diana L., Franceschini, Nora, Franke, Lude H., Girotto, Giorgia, He, Chunyan, Järvelin, Marjo-Riitta, Joshi, Peter K., Kamatani, Yoichiro, Karlsson, Robert, Luan, Jian’an, Lunetta, Kathryn L., Mägi, Reedik, Mangino, Massimo, Medland, Sarah E., Meisinger, Christa, Noordam, Raymond, Nutile, Teresa, Concas, Maria Pina, Polašek, Ozren, Porcu, Eleonora, Ring, Susan M., Sala, Cinzia, Smith, Albert V., Tanaka, Toshiko, van der Most, Peter J., Vitart, Veronique, Wang, Carol A., Willemsen, Gonneke, Zygmunt, Marek, Ahearn, Thomas U., Andrulis, Irene L., Anton-Culver, Hoda, Antoniou, Antonis C., Auer, Paul L., Barnes, Catriona L. K., Beckmann, Matthias W., Berrington de Gonzalez, Amy, Bogdanova, Natalia V., Bojesen, Stig E., Brenner, Hermann, Buring, Julie E., Canzian, Federico, Chang-Claude, Jenny, Couch, Fergus J., Cox, Angela, Crisponi, Laura, Czene, Kamila, Daly, Mary B., Demerath, Ellen W., Dennis, Joe, Devilee, Peter, De Vivo, Immaculata, Dörk, Thilo, Dunning, Alison M., Dwek, Miriam, Eriksson, Johan G., Fasching, Peter A., Fernandez-Rhodes, Lindsay, Ferreli, Liana, Fletcher, Olivia, Gago-Dominguez, Manuela, García-Closas, Montserrat, García-Sáenz, José A., González-Neira, Anna, Grallert, Harald, Guénel, Pascal, Haiman, Christopher A., Hall, Per, Hamann, Ute, Hakonarson, Hakon, Hart, Roger J., Hickey, Martha, Hooning, Maartje J., Hoppe, Reiner, Hopper, John L., Hottenga, Jouke-Jan, Hu, Frank B., Huebner, Hanna, Hunter, David J., Jernström, Helena, John, Esther M., Karasik, David, Khusnutdinova, Elza K., Kristensen, Vessela N., Lacey, James V., Lambrechts, Diether, Launer, Lenore J., Lind, Penelope A., Lindblom, Annika, Magnusson, Patrik K. E., Mannermaa, Arto, McCarthy, Mark I., Meitinger, Thomas, Menni, Cristina, Michailidou, Kyriaki, Millwood, Iona Y., Milne, Roger L., Montgomery, Grant W., Nevanlinna, Heli, Nolte, Ilja M., Nyholt, Dale R., Obi, Nadia, O’Brien, Katie M., Offit, Kenneth, Oldehinkel, Albertine J., Ostrowski, Sisse R., Palotie, Aarno, Pedersen, Ole B., Peters, Annette, Pianigiani, Giulia, Plaseska-Karanfilska, Dijana, Pouta, Anneli, Pozarickij, Alfred, Radice, Paolo, Rennert, Gad, Rosendaal, Frits R., Ruggiero, Daniela, Saloustros, Emmanouil, Sandler, Dale P., Schipf, Sabine, Schmidt, Carsten O., Schmidt, Marjanka K., Small, Kerrin, Spedicati, Beatrice, Stampfer, Meir, Stone, Jennifer, Tamimi, Rulla M., Teras, Lauren R., Tikkanen, Emmi, Turman, Constance, Vachon, Celine M., Wang, Qin, Winqvist, Robert, Wolk, Alicja, Zemel, Babette S., Zheng, Wei, van Dijk, Ko W., Alizadeh, Behrooz Z., Bandinelli, Stefania, Boerwinkle, Eric, Boomsma, Dorret I., Ciullo, Marina, Chenevix-Trench, Georgia, Cucca, Francesco, Esko, Tõnu, Gieger, Christian, Grant, Struan F. A., Gudnason, Vilmundur, Hayward, Caroline, Kolčić, Ivana, Kraft, Peter, Lawlor, Deborah A., Martin, Nicholas G., Nøhr, Ellen A., Pedersen, Nancy L., Pennell, Craig E., Ridker, Paul M., Robino, Antonietta, Snieder, Harold, Sovio, Ulla, Spector, Tim D., Stöckl, Doris, Sudlow, Cathie, Timpson, Nic J., Toniolo, Daniela, Uitterlinden, André, Ulivi, Sheila, Völzke, Henry, Wareham, Nicholas J., Widen, Elisabeth, Wilson, James F., Pharoah, Paul D. P., Li, Liming, Easton, Douglas F., Njølstad, Pål R., Sulem, Patrick, Murabito, Joanne M., Murray, Anna, Manousaki, Despoina, Juul, Anders, Erikstrup, Christian, Stefansson, Kari, Horikoshi, Momoko, Chen, Zhengming, Farooqi, I. Sadaf, Pitteloud, Nelly, Johansson, Stefan, Day, Felix R., Perry, John R. B., and Ong, Ken K.

Published
2024
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28. Large-scale plasma proteomics comparisons through genetics and disease associations

Author

Eldjarn, Grimur Hjorleifsson, Ferkingstad, Egil, Lund, Sigrun H., Helgason, Hannes, Magnusson, Olafur Th., Gunnarsdottir, Kristbjorg, Olafsdottir, Thorunn A., Halldorsson, Bjarni V., Olason, Pall I., Zink, Florian, Gudjonsson, Sigurjon A., Sveinbjornsson, Gardar, Magnusson, Magnus I., Helgason, Agnar, Oddsson, Asmundur, Halldorsson, Gisli H., Magnusson, Magnus K., Saevarsdottir, Saedis, Eiriksdottir, Thjodbjorg, Masson, Gisli, Stefansson, Hreinn, Jonsdottir, Ingileif, Holm, Hilma, Rafnar, Thorunn, Melsted, Pall, Saemundsdottir, Jona, Norddahl, Gudmundur L., Thorleifsson, Gudmar, Ulfarsson, Magnus O., Gudbjartsson, Daniel F., Thorsteinsdottir, Unnur, Sulem, Patrick, and Stefansson, Kari

Published
2023
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29. Genetics and epidemiology of mutational barcode-defined clonal hematopoiesis

Author

Stacey, Simon N., Zink, Florian, Halldorsson, Gisli H., Stefansdottir, Lilja, Gudjonsson, Sigurjon A., Einarsson, Gudmundur, Hjörleifsson, Grimur, Eiriksdottir, Thjodbjorg, Helgadottir, Anna, Björnsdottir, Gyda, Thorgeirsson, Thorgeir E., Olafsdottir, Thorunn A., Jonsdottir, Ingileif, Gretarsdottir, Solveig, Tragante, Vinicius, Magnusson, Magnus K., Jonsson, Hakon, Gudmundsson, Julius, Olafsson, Sigurgeir, Holm, Hilma, Gudbjartsson, Daniel F., Sulem, Patrick, Helgason, Agnar, Thorsteinsdottir, Unnur, Tryggvadottir, Laufey, Rafnar, Thorunn, Melsted, Pall, Ulfarsson, Magnus Ö., Vidarsson, Brynjar, Thorleifsson, Gudmar, and Stefansson, Kari

Published
2023
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30. Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing

Author

Martha M. Zarou, Kevin M. Rattigan, Daniele Sarnello, Engy Shokry, Amy Dawson, Angela Ianniciello, Karen Dunn, Mhairi Copland, David Sumpton, Alexei Vazquez, and G. Vignir Helgason

Subjects
Science
Abstract

Abstract Supporting cell proliferation through nucleotide biosynthesis is an essential requirement for cancer cells. Hence, inhibition of folate-mediated one carbon (1C) metabolism, which is required for nucleotide synthesis, has been successfully exploited in anti-cancer therapy. Here, we reveal that mitochondrial folate metabolism is upregulated in patient-derived leukaemic stem cells (LSCs). We demonstrate that inhibition of mitochondrial 1C metabolism through impairment of de novo purine synthesis has a cytostatic effect on chronic myeloid leukaemia (CML) cells. Consequently, changes in purine nucleotide levels lead to activation of AMPK signalling and suppression of mTORC1 activity. Notably, suppression of mitochondrial 1C metabolism increases expression of erythroid differentiation markers. Moreover, we find that increased differentiation occurs independently of AMPK signalling and can be reversed through reconstitution of purine levels and reactivation of mTORC1. Of clinical relevance, we identify that combination of 1C metabolism inhibition with imatinib, a frontline treatment for CML patients, decreases the number of therapy-resistant CML LSCs in a patient-derived xenograft model. Our results highlight a role for folate metabolism and purine sensing in stem cell fate decisions and leukaemogenesis.

Published
2024
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31. Differential phase reconstruction of microcombs

Author

Twayana, Krishna, Lei, Fuchuan, Ye, Zhichao, Rebolledo-Salgado, Israel, Helgason, Oskar B., Karlsson, Magnus, and Torres-Company, Victor

Subjects
Physics - Optics
Abstract

Measuring microcombs in amplitude and phase provides unique insight into the nonlinear cavity dynamics but spectral phase measurements are experimentally challenging. Here, we report a linear heterodyne technique assisted by electro-optic downconversion that enables differential phase measurement of such spectra with unprecedented sensitivity (-50 dBm) and bandwidth coverage (> 110 nm in the telecommunications range). We validate the technique with a series of measurements, including single cavity and photonic molecule microcombs.

Published
2022

32. Hyperparametric oscillation via bound states in the continuum

Author

Lei, Fuchuan, Ye, Zhichao, Twayana, Krishna, Gao, Yan, Girardi, Marcello, Helgason, Óskar B., Zhao, Ping, and Torres-Company, Victor

Subjects
Physics - Optics
Abstract

Optical hyperparametric oscillation based on the third-order nonlinearity is one of the most significant mechanisms to generate coherent electromagnetic radiation and produce quantum states of light. Advances in dispersion-engineered high-$Q$ microresonators allow for generating signal waves far from the pump and decrease the oscillation power threshold to submilliwatt levels. However, the pump-to-signal conversion efficiency and absolute signal power are low, fundamentally limited by parasitic mode competition and attainable cavity intrinsic $Q$ to coupling $Q$ ratio, i.e., $Q_{\rm i}/Q_{\rm c}$. Here, we use Friedrich-Wintgen bound states in the continuum (BICs) to overcome the physical challenges in an integrated microresonator-waveguide system. As a result, on-chip coherent hyperparametric oscillation is generated in BICs with unprecedented conversion efficiency and absolute signal power. This work not only opens a path to generate high-power and efficient continuous-wave electromagnetic radiation in Kerr nonlinear media but also enhances the understanding of microresonator-waveguide system - an elementary unit of modern photonics.

Published
2022
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33. Publisher Correction: Deficit of homozygosity among 1.52 million individuals and genetic causes of recessive lethality

Author

Oddsson, Asmundur, Sulem, Patrick, Sveinbjornsson, Gardar, Arnadottir, Gudny A., Steinthorsdottir, Valgerdur, Halldorsson, Gisli H., Atlason, Bjarni A., Oskarsson, Gudjon R., Helgason, Hannes, Nielsen, Henriette Svarre, Westergaard, David, Karjalainen, Juha M., Katrinardottir, Hildigunnur, Fridriksdottir, Run, Jensson, Brynjar O., Tragante, Vinicius, Ferkingstad, Egil, Jonsson, Hakon, Gudjonsson, Sigurjon A., Beyter, Doruk, Moore, Kristjan H. S., Thordardottir, Helga B., Kristmundsdottir, Snaedis, Stefansson, Olafur A., Rantapää-Dahlqvist, Solbritt, Sonderby, Ida Elken, Didriksen, Maria, Stridh, Pernilla, Haavik, Jan, Tryggvadottir, Laufey, Frei, Oleksandr, Walters, G. Bragi, Kockum, Ingrid, Hjalgrim, Henrik, Olafsdottir, Thorunn A., Selbaek, Geir, Nyegaard, Mette, Erikstrup, Christian, Brodersen, Thorsten, Saevarsdottir, Saedis, Olsson, Tomas, Nielsen, Kaspar Rene, Haraldsson, Asgeir, Bruun, Mie Topholm, Hansen, Thomas Folkmann, Steingrimsdottir, Thora, Jacobsen, Rikke Louise, Lie, Rolv T., Djurovic, Srdjan, Alfredsson, Lars, Lopez de Lapuente Portilla, Aitzkoa, Brunak, Soren, Melsted, Pall, Halldorsson, Bjarni V., Saemundsdottir, Jona, Magnusson, Olafur Th., Padyukov, Leonid, Banasik, Karina, Rafnar, Thorunn, Askling, Johan, Klareskog, Lars, Pedersen, Ole Birger, Masson, Gisli, Havdahl, Alexandra, Nilsson, Bjorn, Andreassen, Ole A., Daly, Mark, Ostrowski, Sisse Rye, Jonsdottir, Ingileif, Stefansson, Hreinn, Holm, Hilma, Helgason, Agnar, Thorsteinsdottir, Unnur, Stefansson, Kari, and Gudbjartsson, Daniel F.

Published
2023
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34. Deficit of homozygosity among 1.52 million individuals and genetic causes of recessive lethality

Author

Oddsson, Asmundur, Sulem, Patrick, Sveinbjornsson, Gardar, Arnadottir, Gudny A., Steinthorsdottir, Valgerdur, Halldorsson, Gisli H., Atlason, Bjarni A., Oskarsson, Gudjon R., Helgason, Hannes, Nielsen, Henriette Svarre, Westergaard, David, Karjalainen, Juha M., Katrinardottir, Hildigunnur, Fridriksdottir, Run, Jensson, Brynjar O., Tragante, Vinicius, Ferkingstad, Egil, Jonsson, Hakon, Gudjonsson, Sigurjon A., Beyter, Doruk, Moore, Kristjan H. S., Thordardottir, Helga B., Kristmundsdottir, Snaedis, Stefansson, Olafur A., Rantapää-Dahlqvist, Solbritt, Sonderby, Ida Elken, Didriksen, Maria, Stridh, Pernilla, Haavik, Jan, Tryggvadottir, Laufey, Frei, Oleksandr, Walters, G. Bragi, Kockum, Ingrid, Hjalgrim, Henrik, Olafsdottir, Thorunn A., Selbaek, Geir, Nyegaard, Mette, Erikstrup, Christian, Brodersen, Thorsten, Saevarsdottir, Saedis, Olsson, Tomas, Nielsen, Kaspar Rene, Haraldsson, Asgeir, Bruun, Mie Topholm, Hansen, Thomas Folkmann, Steingrimsdottir, Thora, Jacobsen, Rikke Louise, Lie, Rolv T., Djurovic, Srdjan, Alfredsson, Lars, Lopez de Lapuente Portilla, Aitzkoa, Brunak, Soren, Melsted, Pall, Halldorsson, Bjarni V., Saemundsdottir, Jona, Magnusson, Olafur Th., Padyukov, Leonid, Banasik, Karina, Rafnar, Thorunn, Askling, Johan, Klareskog, Lars, Pedersen, Ole Birger, Masson, Gisli, Havdahl, Alexandra, Nilsson, Bjorn, Andreassen, Ole A., Daly, Mark, Ostrowski, Sisse Rye, Jonsdottir, Ingileif, Stefansson, Hreinn, Holm, Hilma, Helgason, Agnar, Thorsteinsdottir, Unnur, Stefansson, Kari, and Gudbjartsson, Daniel F.

Published
2023
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36. Validated, high-resolution, non-linear, explicit finite element models for simulating screw - bone interaction

Author

Yijun Zhou, Benedikt Helgason, Stephen J. Ferguson, and Cecilia Persson

Subjects
Screw insertion, Screw push-in, Explicit finite element model, Trabecular bone, Damage model, Medical technology, R855-855.5
Abstract

Background and Objective: Primary stability evaluation of screw implants through pull-out or push-in experiments is commonly used to investigate the mechanism of screw loosening. Numerical models simulating these testing methods could provide an enhanced understanding of the underlying attachment mechanisms as well as save time and cost in the development of new screws. However, previous numerical models have been limited by compromises between modelling the trabecular structure at high resolution versus incorporating sophisticated mechanical properties and boundary conditions, leading to overestimated mechanical performance. The aim of this study was to overcome these limitations. Methods: We developed explicit models incorporating the microstructure of trabecular bone, with frictional contact, and a non-linear material model incorporating damage. One model digitally inserted the screw into the trabecular bone structure using Boolean operations, while another model simulated the screw's rotational insertion. Results: The results showed a strong correlation between numerical and experimental results (R2: 0.54–0.93) for force-displacement response in terms of stiffness and strength. We found that the damage induced by the screw insertion process is an important factor to be considered, as the absence of modelling it led to an overestimated stiffness in previous studies. Conclusions: The study highlights the importance of including frictional contact and also identified screw insertion damage as an important part of the simulating screw-bone interaction. Our findings demonstrate the potential of explicit finite element models for accurately replicating experimental push-in results and optimizing orthopaedic screws. The code is available at https://github.com/zhou436/Bone-Screw-Constructs-eFEM.

Published
2024
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37. Fast and Robust Femur Segmentation from Computed Tomography Images for Patient-Specific Hip Fracture Risk Screening

Author

Bjornsson, Pall Asgeir, Baker, Alexander, Fleps, Ingmar, Pauchard, Yves, Palsson, Halldor, Ferguson, Stephen J., Sigurdsson, Sigurdur, Gudnason, Vilmundur, Helgason, Benedikt, and Ellingsen, Lotta Maria

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Computer Science - Computer Vision and Pattern Recognition
Abstract

Osteoporosis is a common bone disease that increases the risk of bone fracture. Hip-fracture risk screening methods based on finite element analysis depend on segmented computed tomography (CT) images; however, current femur segmentation methods require manual delineations of large data sets. Here we propose a deep neural network for fully automated, accurate, and fast segmentation of the proximal femur from CT. Evaluation on a set of 1147 proximal femurs with ground truth segmentations demonstrates that our method is apt for hip-fracture risk screening, bringing us one step closer to a clinically viable option for screening at-risk patients for hip-fracture susceptibility., Comment: This article has been accepted for publication in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, published by Taylor & Francis

Published
2022
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38. Corroborating written history with ancient DNA: The case of the Well-man described in an Old Norse saga

Author

Ellegaard, Martin R., Ebenesersdóttir, S. Sunna, Moore, Kristjan H.S., Petersén, Anna, Vågene, Åshild J., Bieker, Vanessa C., Denham, Sean D., Cavalleri, Gianpiero L., Gilbert, Edmund, Werge, Thomas, Hansen, Thomas F., Kockum, Ingrid, Alfredsson, Lars, Olsson, Tomas, Hovig, Eivind, Gilbert, M. Thomas P., Stefánsson, Kári, Stenøien, Hans K., Helgason, Agnar, and Martin, Michael D.

Published
2024
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39. Upfront resection versus no resection of the primary tumor in patients with synchronous metastatic colorectal cancer: the randomized phase III CAIRO4 study conducted by the Dutch Colorectal Cancer Group and the Danish Colorectal Cancer Group

Author

Vincent, Jeroen, Wegdam, Johannes A., Haberkorn, Brigitte C.M., van der Harst, Erwin, Hendriks, Mathijs P., Schreurs, W.H. Hermien, Cense, Huib A., Rietbroek, Ron C., de Gier, Marie-José, van Breugel, Edwin A., de Vos, Aad I., Brosens, Rebecca P.M., Doornebosch, P.G., de Jongh, Felix E., Vles, Wouter J., den Boer, Marien O., Leijtens, Jeroen W.A., Gelderblom, A.J. Hans, Peeters, Koen C.M.J., Kuenen, Bart C., Pultrum, Bareld B., van Dodewaard-de Jong, Joyce M., Consten, Esther C.J., van de Wouw, A.J. Yes, Konsten, J.L.M., Hoekstra, R., Lutke Holzik, Martijn F., Vos, Allert H., van Hoogstraten, M.J., Schlesinger, Nis H., Creemers, Geert-Jan, de Hingh, Ignace H.J.T., Kjær, Monica L., Petersen, Lone N., Seiersen, Michael, Altaf, Rahim, van Cruijsen, Hester, Hess, Daniël A., van Leeuwen-Snoeks, Lobke L., Pronk, Apollo, Baeten, Coen I.M., van der Deure, Wendy M., Bosscha, Koop, Schut, Heidi, Leclercq, W.K.G., Simkens, L.H.J., Reijnders, Koen, van Arkel, Kees, van Grevenstein, W.M.U. Helma, van de Ven, Anthony W.H., Vuylsteke, Ronald J.C.L.M., Kuijer, Philomeen, Bakker, Sandra D., Goei, Hauwy, Helgason, Helgi H., van Acker, Gijs J.D., Temizkan, Mehmet, van Tilburg, Marc W.A., Gerhards, Michael F., Kerver, E.D., Gootjes, Elske, Nieboer, Peter, Bleeker, Wim A., Bleeker, G.R., van der Kruijssen, D.E.W., Elias, S.G., van de Ven, P.M., van Rooijen, K.L., Lam-Boer, J.’t, Mol, L., Punt, C.J.A., Sommeijer, D.W., Tanis, P.J., Nielsen, J.D., Yilmaz, M.K., van Riel, J.M.G.H., Wasowiz-Kemps, D.K., Loosveld, O.J.L., van der Schelling, G.P., de Groot, J.W.B., van Westreenen, H.L., Jakobsen, H.L., Fromm, A.L., Hamberg, P., Verseveld, M., Jaensch, C., Liposits, G.I., van Duijvendijk, P., Oulad Hadj, J., van der Hoeven, J.A.B., Trajkovic, M., de Wilt, J.H.W., and Koopman, M.

Published
2024
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41. Leukaemia exposure alters the transcriptional profile and function of BCR::ABL1 negative macrophages in the bone marrow niche

Author

Amy Dawson, Martha M. Zarou, Bodhayan Prasad, Joana Bittencourt-Silvestre, Désirée Zerbst, Ekaterini Himonas, Ya-Ching Hsieh, Isabel van Loon, Giovanny Rodriguez Blanco, Angela Ianniciello, Zsombor Kerekes, Vaidehi Krishnan, Puneet Agarwal, Hassan Almasoudi, Laura McCluskey, Lisa E. M. Hopcroft, Mary T. Scott, Pablo Baquero, Karen Dunn, David Vetrie, Mhairi Copland, Ravi Bhatia, Seth B. Coffelt, Ong Sin Tiong, Helen Wheadon, Sara Zanivan, Kristina Kirschner, and G. Vignir Helgason

Subjects
Science
Abstract

Abstract Macrophages are fundamental cells of the innate immune system that support normal haematopoiesis and play roles in both anti-cancer immunity and tumour progression. Here we use a chimeric mouse model of chronic myeloid leukaemia (CML) and human bone marrow (BM) derived macrophages to study the impact of the dysregulated BM microenvironment on bystander macrophages. Utilising single-cell RNA sequencing (scRNA-seq) of Philadelphia chromosome (Ph) negative macrophages we reveal unique subpopulations of immature macrophages residing in the CML BM microenvironment. CML exposed macrophages separate from their normal counterparts by reduced expression of the surface marker CD36, which significantly reduces clearance of apoptotic cells. We uncover aberrant production of CML-secreted factors, including the immune modulatory protein lactotransferrin (LTF), that suppresses efferocytosis, phagocytosis, and CD36 surface expression in BM macrophages, indicating that the elevated secretion of LTF is, at least partially responsible for the supressed clearance function of Ph- macrophages.

Published
2024
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42. Power-efficient soliton microcombs

Author

Helgason, Óskar B., Girardi, Marcello, Ye, Zhichao, Lei, Fuchuan, Schröder, Jochen, and Company, Victor Torres

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

Laser frequency combs are enabling some of the most exciting scientific endeavours in the 21st century, ranging from the development of optical clocks to the calibration of the astronomical spectrographs used for searching Earth-like exoplanets. Today, dissipative Kerr solitons generated in microresonators offer the prospect of attaining frequency combs in miniaturized systems by capitalizing on advances in photonic integration. Most of the applications based on soliton microcombs rely on tuning a continuous-wave laser into a longitudinal mode of a microresonator whose dimensions are engineered to display anomalous dispersion at the pump laser frequency. In this configuration, however, nonlinear physics precludes from attaining dissipative Kerr solitons with high power conversion efficiency, with typical comb powers amounting to ~1% of the available laser power. Here, we demonstrate that this fundamental limitation can be overcome by inducing a controllable frequency shift to a selected cavity resonance. Experimentally, we realize this shift using two linearly coupled anomalous-dispersion microresonators (a photonic molecule), resulting in a coherent dissipative Kerr soliton with a conversion efficiency exceeding 50% and excellent line spacing stability. We describe the physical soliton dynamics in this configuration, and discover the system displays unusual characteristics, such as the possibility to backwards initiate solitons and stable operation with a blue detuned pump laser. By optimizing the microcomb power available on chip, these results facilitate the practical implementation of a scalable integrated photonic architecture for energy-efficient applications.

Published
2022
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43. Rare variants with large effects provide functional insights into the pathology of migraine subtypes, with and without aura

Author

Bjornsdottir, Gyda, Chalmer, Mona A., Stefansdottir, Lilja, Skuladottir, Astros Th., Einarsson, Gudmundur, Andresdottir, Margret, Beyter, Doruk, Ferkingstad, Egil, Gretarsdottir, Solveig, Halldorsson, Bjarni V., Halldorsson, Gisli H., Helgadottir, Anna, Helgason, Hannes, Hjorleifsson Eldjarn, Grimur, Jonasdottir, Adalbjorg, Jonasdottir, Aslaug, Jonsdottir, Ingileif, Knowlton, Kirk U., Nadauld, Lincoln D., Lund, Sigrun H., Magnusson, Olafur Th., Melsted, Pall, Moore, Kristjan H. S., Oddsson, Asmundur, Olason, Pall I., Sigurdsson, Asgeir, Stefansson, Olafur A., Saemundsdottir, Jona, Sveinbjornsson, Gardar, Tragante, Vinicius, Unnsteinsdottir, Unnur, Walters, G. Bragi, Zink, Florian, Rødevand, Linn, Andreassen, Ole A., Igland, Jannicke, Lie, Rolv T., Haavik, Jan, Banasik, Karina, Brunak, Søren, Didriksen, Maria, T. Bruun, Mie, Erikstrup, Christian, Kogelman, Lisette J. A., Nielsen, Kaspar R., Sørensen, Erik, Pedersen, Ole B., Ullum, Henrik, Masson, Gisli, Thorsteinsdottir, Unnur, Olesen, Jes, Ludvigsson, Petur, Thorarensen, Olafur, Bjornsdottir, Anna, Sigurdardottir, Gudrun R., Sveinsson, Olafur A., Ostrowski, Sisse R., Holm, Hilma, Gudbjartsson, Daniel F., Thorleifsson, Gudmar, Sulem, Patrick, Stefansson, Hreinn, Thorgeirsson, Thorgeir E., Hansen, Thomas F., and Stefansson, Kari

Published
2023
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50. Deficit of homozygosity among 1.52 million individuals and genetic causes of recessive lethality

Author

Asmundur Oddsson, Patrick Sulem, Gardar Sveinbjornsson, Gudny A. Arnadottir, Valgerdur Steinthorsdottir, Gisli H. Halldorsson, Bjarni A. Atlason, Gudjon R. Oskarsson, Hannes Helgason, Henriette Svarre Nielsen, David Westergaard, Juha M. Karjalainen, Hildigunnur Katrinardottir, Run Fridriksdottir, Brynjar O. Jensson, Vinicius Tragante, Egil Ferkingstad, Hakon Jonsson, Sigurjon A. Gudjonsson, Doruk Beyter, Kristjan H. S. Moore, Helga B. Thordardottir, Snaedis Kristmundsdottir, Olafur A. Stefansson, Solbritt Rantapää-Dahlqvist, Ida Elken Sonderby, Maria Didriksen, Pernilla Stridh, Jan Haavik, Laufey Tryggvadottir, Oleksandr Frei, G. Bragi Walters, Ingrid Kockum, Henrik Hjalgrim, Thorunn A. Olafsdottir, Geir Selbaek, Mette Nyegaard, Christian Erikstrup, Thorsten Brodersen, Saedis Saevarsdottir, Tomas Olsson, Kaspar Rene Nielsen, Asgeir Haraldsson, Mie Topholm Bruun, Thomas Folkmann Hansen, DBDS Genomic Consortium, Thora Steingrimsdottir, Rikke Louise Jacobsen, Rolv T. Lie, Srdjan Djurovic, Lars Alfredsson, Aitzkoa Lopez de Lapuente Portilla, Soren Brunak, Pall Melsted, Bjarni V. Halldorsson, Jona Saemundsdottir, Olafur Th. Magnusson, Leonid Padyukov, Karina Banasik, Thorunn Rafnar, Johan Askling, Lars Klareskog, Ole Birger Pedersen, Gisli Masson, Alexandra Havdahl, Bjorn Nilsson, Ole A. Andreassen, Mark Daly, Sisse Rye Ostrowski, Ingileif Jonsdottir, Hreinn Stefansson, Hilma Holm, Agnar Helgason, Unnur Thorsteinsdottir, Kari Stefansson, and Daniel F. Gudbjartsson

Subjects
Science
Abstract

Abstract Genotypes causing pregnancy loss and perinatal mortality are depleted among living individuals and are therefore difficult to find. To explore genetic causes of recessive lethality, we searched for sequence variants with deficit of homozygosity among 1.52 million individuals from six European populations. In this study, we identified 25 genes harboring protein-altering sequence variants with a strong deficit of homozygosity (10% or less of predicted homozygotes). Sequence variants in 12 of the genes cause Mendelian disease under a recessive mode of inheritance, two under a dominant mode, but variants in the remaining 11 have not been reported to cause disease. Sequence variants with a strong deficit of homozygosity are over-represented among genes essential for growth of human cell lines and genes orthologous to mouse genes known to affect viability. The function of these genes gives insight into the genetics of intrauterine lethality. We also identified 1077 genes with homozygous predicted loss-of-function genotypes not previously described, bringing the total set of genes completely knocked out in humans to 4785.

Published
2023
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