263134 research outputs found
Sort by
Copy-Number Profiling and Methylation-Based Tumor Typing during Prenatal Cell-Free DNA Screening
No full textBACKGROUND: Prenatal cell-free DNA (cfDNA) screening is primarily designed to detect fetal chromosomal abnormalities, but can also identify aneuploidies derived from other tissues, including cancer. The identification of aneuploidies of unknown origin during prenatal cfDNA screening can lead to time-consuming multistage investigations and anxiety for the expecting mother. METHODS: To expedite the identification of the origin of copy-number aberrations and guide clinical management of such profiles suggestive of maternal malignancy, we developed a methylation and aneuploidy-aware prenatal screening pipeline. Plasma cfDNA is enzymatically converted to identify the methylated cytosines during sequencing. The tissue of origin is predicted by leveraging a cell-type-specific methylome atlas into our methylation-based deconvolution algorithm, MetDecode. RESULTS: We demonstrate that aneuploidy profiling on enzymatically converted cfDNA enables the identification of placental and cancer-derived aneuploidies with similar accuracy compared with conventional prenatal cfDNA screening. The methylation-based deconvolution pinpointed the tumor origin correctly in 91.67% of the pregnant women with a tumor fraction >3%. CONCLUSION: Methylome and aneuploidy-aware cfDNA screening could substantially improve the diagnostic processes, pinpoint the origins of aneuploidy and improve cancer management during pregnancy.sponsorship: This study was supported by the Research Foundation-Flanders [FWO-Vlaanderen; 1S74420N to S. Tuveri, 1S93025N to A. Pagliazzi, SBO grant S003422N to J.R. Vermeesch], Stichting tegen Kanker [STK grant 2018-134 to J.R. Vermeesch and F. Amant], Kom op tegen Kanker [KotK grant 2018/11468 to J.R. Vermeesch and F. Amant], Foundation against cancer to J.R. Vermeesch (C/2024/2808), Horizon 2020 [No 824110-EASI-Genomics to J.R. Vermeesch], Horizon Europe Health CAN.HEAL project (CAN.HEAL, contract number 101080009, to J.R. Vermeesch and L. Lenaerts), KU Leuven [C1-C14/18/092 and C14/22/125 to J.R. Vermeesch and C3/20/100 to J.R. Vermeesch]. (Research Foundation-Flanders [FWO-Vlaanderen]|1S74420N, Research Foundation-Flanders [FWO-Vlaanderen]|1S93025N, Research Foundation-Flanders [FWO-Vlaanderen]|S003422N, Stichting tegen Kanker [STK]|2018-134, Kom op tegen Kanker [KotK]|2018/11468, Foundation against cancer|C/2024/2808, EASI-Genomics|824110, Horizon Europe Health CAN.HEAL project (CAN.HEAL)|101080009, KU Leuven|C1-C14/18/092, KU Leuven|C14/22/125, KU Leuven|C3/20/100)status: Published onlin
Influence of Tubal Patency on Endometriosis Recurrence: a Retrospective Matched Case-control Study.
No full textSTUDY OBJECTIVE: To study if bilateral non-patency of fallopian tubes is correlated with a lower recurrence rate of endometriosis. DESIGN: Retrospective 2:1 matched case control study. SETTING: University hospital with tertiary referral center for fertility and endometriosis surgery in Leuven, Belgium. PATIENTS: All patients undergoing complete laparoscopic excision of any rASRM-stage endometriosis between 2010 and 2014 (n=896). INTERVENTION: Comparison between patients with bilateral non-patent or absent fallopian tubes versus matched controls with at least one patent fallopian tube. MEASUREMENTS AND MAIN RESULTS: Primary outcome was the recurrence rate which was analyzed on 4 levels: overall recurrence, symptom recurrence, recurrence on imaging and need for reintervention. Out of 896 patients, 49 had bilateral non-patent or absent fallopian tubes. These cases were compared with 98 matched controls with at least one patent fallopian tube. Symptoms recurred in 12.2% of the cases (n=6) and 25.5% of the controls (n =25) (P=0.09). Recurrence was confirmed by imaging in 8% of the cases (n=4) and in 10.2% of the controls (n=10) (P=0.77). In 3 patients of the case group and in 12 patients of the control group, there was a need for reintervention (P=0.39). Within this subgroup, recurrence of endometriosis was histologically confirmed in none of the patients of the case group and in 5 patients of the control group (P=0.51). CONCLUSION: This study did not observe a statistically significant reduction in endometriosis recurrence in patients with bilateral occlusion/absence of the fallopian tubes after endometriosis surgery. A type II error may count for this result.status: Published onlin
Embodiment, identity formation, and psychological late effects in adolescent and emerging adult cancer survivors
No full textOBJECTIVE: A cancer experience may complicate how young survivors relate to their bodies. To enhance our understanding, it is necessary to move beyond a narrow focus on bodily appearance. The current study examines how the multidimensional construct of embodiment is related to the developmental trajectories of identity formation and psychological late effects in young survivors. METHODS: Survivors completed self-report questionnaires on embodiment at Timepoint 4 and on identity synthesis and confusion, posttraumatic stress symptoms (PTSS), cancer-related worries, and benefit finding at Timepoints 1-3. Using structural equation modeling, embodiment 3 years later was predicted by developmental trajectories of identity and psychological late effects of cancer. RESULTS: Higher initial levels of identity synthesis and lower initial levels of identity confusion, PTSS, and cancer-related worries were associated with higher levels of embodiment 3 years later. Increases in identity synthesis and decreases in identity confusion were associated with higher levels of embodiment 3 years later. CONCLUSIONS: This longitudinal study highlights the significant value of embodiment in understanding the bodily experiences of young survivors, and reveals how embodiment is related to identity development and psychological late effects of cancer.sponsorship: The work conducted for this article was supported by research grants from the Internal Funds of the Research Council KU Leuven (C14/21/052 and C14/15/036) and from FWO Research Foundation-Flanders, Belgium (1126418N and G0D3521N). (Internal Funds of the Research Council KU Leuven|C14/21/052, Internal Funds of the Research Council KU Leuven|C14/15/036, FWO Research Foundation-Flanders, Belgium|1126418N, FWO Research Foundation-Flanders, Belgium|G0D3521N)status: Publishe
Een Oost-Aziatisch ‘Sonisch Rijk’: Platenmaatschappijen, de Staat, en Populaire Muziek in Japan tussen 1910 en 1945
No full textThis dissertation examines the interaction between record companies and the state in the Empire of Japan between 1910 and 1945. The primary aim is to provide a novel perspective on the impact of this private-public relationship with a special focus on three dimensions: information gathering, the acquisition of materials necessary to produce sound media, and the development and spread of jazz and popular music during this period. A secondary aim of the dissertation is to integrate Japan's instructive case into the hitherto Western-dominated global history of the recording industry.
To achieve this, the dissertation uses the concept 'sonic empire' which is characterised by the following elements. The behaviour of record companies during this period mirrored the imperialistic logics of expansion of political empires to obtain hegemony of markets seen as 'their' spheres of interest. Herein, such expansion also went along with informal empire. Although they owned the means and technology to produce sound media and the musical content, record companies resisted government control over their output. On the other hand, they cooperated with the same state depending on the situation. In addition, in its early growth as 'sonic empire', record companies had a symbiotic relationship with the state to obtain systematic information on new markets.
The period under scrutiny is highly relevant because it illustrates the impact of varying congruences between 'sonic empire' and political empire.
During the 1910s, emergent Japanese record companies sought to expand to overseas markets which were often colonial in nature. They received support from the state in the form of vital commercial intelligence. Although initially successful in the attempt to establish their 'sonic empires', these record companies failed financially at the end of the decade due to convergence of domestic and global issues. As a result, a period of takeovers and mergers began wherein the American managed Nihon chikuonki shōkai emerged as the dominant force.
In the 1920s, a society of mass consumerism and culture emerged in Japan, and the gramophone became an important medium for sound. The Japanese state sought to manage the development of this mass medium as well as the companies that produced it with a so-called 'Gramophone Record Recommendation and Authorisation Project'. However, despite cooperation between the private and public sector to promote morally 'good' music, it struggled to contain the influence of record companies.
The following two decades saw again varying grades of congruence. Notably, Nippon Victor, initially an American subsidiary to the Victor Talking Machine Company at its founding in 1927, serves as a primary example of such a 'sonic empire'. The company established a network of branches and retailers which it instructed how to advertise. The company also used a global network of suppliers to obtain the materials to manufacture its gramophone and records. It shows the semi-congruence with the Empire of Japan until 1937, when it became a fully Japanese company during a decade of unprecedented numbers of gramophone records sold and war. 1945 marked the end of Japan's empire and, hence, also of the tense relation - between collaboration and conflict - with the record companies as 'sonic empires'.
The choice for jazz as special focus in this dissertation is because of two reasons. First, record companies in the 1920s and 1930s generated most profits from jazz and hayariuta (popular songs) that contained influence from jazz. Second, like elsewhere in the world, this musical genre had a significant impact on Japan's society and culture in this period. In fact, the state deemed it necessary to intervene with recommendation and censorship projects. Therefore, jazz and popular music serve as one lens to highlight the complex relationship between record companies and the state in Japan.
A key finding is that the interaction between record companies and the state in Japan is to be regarded as a complex, dynamic relationship. It evolved continuously between cooperation and opposition during the period 1910 and 1945. In addition, the dissertation emphasises that the three dimensions are interrelated and must be taken together to understand this private-public relationship.
Another finding of the dissertation is that the First World War formed a crucial catalyst for the Japanese recording industry in two ways. It marked its path dependent development in the following decades regarding cooperation with the state. In addition, the desire of emerging Japanese record companies to expand into Asian markets during the First World War to gain hegemony in the markets within other political empires, was by itself a form of imperial logic, using commercial intelligence from the state.
Ultimately, sustained patterns of exchange in a globalising economy during a period of colonial empires around the world influenced the development of Japan's record companies. Hence, the dissertation provides a significant non-Western-centred perspective to reconsider the global history of the recording industry in the first half of the twentieth century.status: Publishe
A surface quality evaluation method for establishing image-surface causal chain in X ray computed tomography measurement
No full textstatus: Accepte
Schakelingsfysica van FeFET-geheugenapparaten met een oxide-halfgeleiderkanaal
No full textThe rapid growth of AI training and edge inference raises stringent requirements on memory latency, bandwidth, energy, and 3D integrability. HfO2-based Ferroelectric Field-Effect Transistors (FeFETs) offer a path to low-latency, non-volatile memory cells compatible with monolithic 3D integration for high density. Employing an oxide-semiconductor IGZO channel enables a true metal-ferroelectric-semiconductor stack with reduced charge trapping and BEOL compatibility. However, the scarcity of holes in wide-bandgap IGZO challenges an efficient erase operation, which requires positive charges to balance negative polarization. This thesis elucidates charge-balance mechanisms during ferroelectric switching, and develops device designs that stabilize the switching and deliver high endurance.
We first build an electrostatic description of ferroelectric switching in the metal/ferroelectric/IGZO stack that accounts for the sources of positive charge in the absence of holes. Partially ionized donor states are identified as the positive screening charges that balance negative polarization during erase. Through switching kinetics evaluations on ferroelectric capacitors and transistors, we find that erase proceeds more slowly than program. These results reveal that the time needed to complete erase is the key bottleneck for low-latency IGZO-channel FeFETs.
On planar back-gated FeFET devices, we implement gate-stack optimization to stabilize the cycling, and accelerate erase in short-channel devices due to the source/drain fringing fields. The extrinsic breakdown is suppressed with source/drain area scaling, and IGZO-channel composition tuning allows for enlarging the memory window and stabilizing the threshold voltage. Together, these strategies enable microsecond-scale erase and endurance up to 1e10 cycles.
Moving from planar to 3D devices, we demonstrate vertically integrated IGZO-channel FeFET cells connected in NAND strings. The devices exhibit ferroelectric memory window yet show the expected slow erase in long-channel strings where the fringing field is weak.
To address the slow-erase issue in long-channel FeFETs, we propose a dual-gate structure that strengthens electrostatic control over the floating IGZO channel. Measurements and simulations confirm faster and more complete switching in dual-gate FeFETs even at large channel lengths, indicating the feasibility of fast-erasable 3D IGZO-channel FeFETs through back-gate control.
Overall, this work advances IGZO-channel FeFET memory from physical understanding to device design across planar and 3D forms. It provides fundamental insights, device-engineering guidelines, and integration directions that support low-latency operation, reliable cycling, and practical 3D implementation of IGZO-channel FeFET memories.status: Publishe
Metaaloxide-interlagen voor verbeterde SOT-efficiëntie in Pt/Co voor SOT-MRAM-toepassingen
No full textThe continued scaling of memory devices requires energy-efficient technologies. Spin-orbit torque magnetic random-access memory (SOT-MRAM) offers fast and reliable switching using spin currents generated in a heavy metal, such as Pt, to manipulate the magnetization of an adjacent ferromagnet, like Co. However, low SOT efficiency necessitates high switching currents, limiting energy performance.
In this work, ultrathin (few nanometers) metal-oxide interlayers are introduced in Pt/Co heterostructures to improve SOT efficiency. While oxides such as NiO at the interface have been reported to enhance SOT, the underlying mechanisms remain unclear, and systematic studies of structural and magnetic properties are lacking. In this thesis, the structural, magnetic, and spin-transport properties of Pt/oxide/Co systems were systematically investigated as a function of interlayer thickness and annealing temperature, using NiO, MgO, and CoOx as oxide interlayers. Atomic-scale interface structure and magnetic depth profiles were revealed by atom probe tomography and spallation-source-based polarized neutron reflectometry. Comparison across multiple oxides revealed the key interfacial properties governing SOT enhancement.
The different interlayers induce distinct structural effects: NiO intermixes with Co upon annealing, MgO remains stable but enables Co diffusion toward Pt forming Pt-Co, and CoOx undergoes phase separation into Co-rich crystalline and O-rich disordered regions. Despite these differences, the Co magnetic properties are largely preserved, with perpendicular magnetic anisotropy observed after annealing, attributed to Pt-Co or Co-O hybridization. Annealing is essential to enhance these interfacial effects and maximize the SOT efficiency, which increases up to fourfold for intermediate oxide thicknesses (1.5-2 nm)), pointing toward oxygen-mediated interfacial effects as the unifying mechanism. Among the investigated oxides, MgO emerges as the most promising interlayer for device integration, combining high SOT efficiency at 400ºC annealing and 2nm thickness with compatibility with established MRAM processes.
This systematic study shows how ultrathin metal-oxide interlayers impact interfacial chemistry, spin transport, and magnetic properties, and demonstrates that interfacial effects are the key mechanism enhancing spin-orbit torque efficiency, providing fundamental insight for designing next-generation, energy-efficient SOT-MRAM devices.status: Publishe
Forgetting as an active process: Attentional withdrawal following a forget instruction
No full textIntentional forgetting, commonly studied using a directed forgetting paradigm, can disrupt memory performance. Beyond verbal report, attenuation of physiological fear responding to emotional associations has also been demonstrated following a simple instruction to forget. Discussion nevertheless persists about the mechanisms underlying this directed forgetting effect, and, by extension, the active or passive nature of forgetting. In recent years, the body of research suggesting that forgetting is an active process has expanded, with attentional withdrawal among its proposed mechanisms. In the current study, we demonstrate that both verbal memory and physiological fear responding to emotional stimuli were disrupted due to the instruction to forget, using a non-differential fear conditioning paradigm. Using an inhibition of return task, we also show that attention was withdrawn more vigorously from items accompanied by an instruction to forget, and that the magnitude of this withdrawal effect was correlated with the directed forgetting effect across individuals. Our findings corroborate the proposition of stronger attentional withdrawal upon the presentation of a forget instruction, and thus the potential involvement of active attentional withdrawal in directed forgetting of emotional memories.sponsorship: This research was funded through a personal fellowship awarded to Anastasia Chalkia (12R8622N) from the Research Foundation Flanders (FWO). This research was also supported by an infrastructure grant from the FWO and the Research Fund of KU Leuven, Belgium (I011320N; AKUL/19/06). (Research Foundation Flanders (FWO)|12R8622N, FWO, Research Fund of KU Leuven, Belgium|I011320N, Research Fund of KU Leuven, Belgium|AKUL/19/06)status: Published onlin
A Domain Ontology for Ishikawa Diagrams to Enhance Root Cause Analysis
No full textIshikawa diagrams, also known as fishbone or cause-and-effect diagrams, are a widely known visual tool for performing root cause analysis (RCA). Although Ishikawa diagrams originated in the manufacturing sector, the tool is also actively used in other areas such as healthcare or business due to its simple structure, which requires little or no training beforehand. Though Ishikawa diagrams are valuable sources of knowledge, they lack rich semantics to effectively process them. As a result, knowledge engineers tend to ignore Ishikawa diagrams and choose other means to collect knowledge, although domain experts are familiar with the RCA tool and it is highly accepted. This paper presents the Ishikawa diagram ontology which enables the explicit modeling of Ishikawa diagrams as visual artifacts, their encoded knowledge and the process of their creation by reusing and extending existing ontologies. The ontology was developed using the LOT methodology. We have created a dataset of Ishikawa diagrams and describe a fictional use case to illustrate the intended use of the presented ontology.status: Published onlin
Navigating complexities: differential diagnosis of thrombotic microangiopathies in pregnancy - a case report
No full textBACKGROUND: Thrombotic microangiopathy (TMA) during pregnancy is most commonly due to hypertensive disorders such as the hemolysis, elevated liver, low platelet (HELLP) syndrome and preeclampsia (PE). In these cases, delivery is the primary therapeutic intervention. However, distinguishing these pregnancy-related TMAs from other etiologies is critical, as alternative or coexisting causes may necessitate additional diagnostic and therapeutic strategies. CASE REPORT: We report a complex and unique case of a pregnant patient with prior bariatric surgery who developed a severe early-onset HELLP. The clinical course was further complicated by posterior reversible encephalopathy syndrome (PRES). Laboratory evaluation demonstrated severe vitamin B12 deficiency and glucose-6-phosphate dehydrogenase deficiency. Due to the rapid maternal deterioration, pregnancy termination was necessary to prevent further maternal morbidity. CONCLUSIONS: This case highlights the complexity of diagnosing and managing TMA during pregnancy. It emphasizes the need for clinical vigilance and a multidisciplinary approach to identify coexisting metabolic or genetic conditions that may influence both maternal and fetal outcomes.status: Published onlin