open_UMR

Aaron Beller

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Welcome to open_UMR!

Open_UMR is a cross faculty publication hub. We collect scientific publications, resources, research data and software from members of Philipps-University Marburg and make it openly accessible. To ensure high standards of quality and re-usability, submissions to open_UMR are subject to curation.

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Recent Submissions

Open Access
Microscopic modelling of exciton-polaritons in two-dimensional materials
(2026-09-29)
König, Jonas Konstantin
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Malic, Ermin
;
Leisgang, Nadine
Study of excitonic and polaritonic properties in two-dimensional TMDs and halide perovskites under external fields. Focus on magnetic-field-induced dark exciton brightening, anisotropic polariton states, and the resulting non-equilibrium relaxation bottlenecks and ultrafast transport. In addition, detailed microscopic characterization of polariton-polariton interaction mechanisms, including the role of electric-field-tunable interlayer dipole interactions in homobilayers.
Open Access
Interventionelle Sonographie bei onkologischen Patienten: Langzeitergebnisse der ultraschallgesteuerten Tumorbiopsie und Radiofrequenzablation von Lebertumoren
(2026-09-10)
Weilert, Hauke
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Mahnken, Andreas H.
;
Görg, Christian
Percutaneous image-guided procedures have become an integral component in the diagnosis and treatment of patients with oncological diseases. Ultrasound-guided interventions are associated with several advantages, including immediate availability, absence of ionizing radiation and continuous real-time visualization of the puncture trajectory, facilitating precise lesion targeting and avoidance of injury to adjacent structures. Interventional ultrasound is a versatile tool that can be applied for diagnostic purposes, including tumor biopsies, as well as for therapeutic interventions, such as radiofreuquency ablation. The following studies about these areas of application address different outcomes, with one focusing on safety and the other on long-term survival. With regard to diagnostic tumor biopsies, the study „ Incidence, timing and risk factors of severe complications after percutaneous ultrasound-guided tumor biopsy: a proposal for safe aftercare based on 30-years´ experience”, published in May 2025 in the Journal BMC Medical Imaging, aimed to evaluate the safety and appropriate post-procedural observation period following ultrasound-guided Tru-Cut biopsies of thoracic or abdominal tumors. Data from 7.494 patients who underwent tumor biopsies were analysed to identify serious biopsy-related complications (i.e., complications requiring therapeutic intervention, defined as grade ≥2 according to the Clavien-Dindo classification). These complications were classified according to time of occurrence as acute (<6 hours), subacute (6-24 hours), or delayed (>24 hours). A total of 29 (0.39%) serious complications occurred, including 8 acute (28%), 18 subacute (62%) and 3 delayed (10%) events. The most frequent complication was bleeding (90%, 26/29), followed by pneumothorax (10%, 3/29). The incidence of bleeding exceeded 1% at splenic (1.6%) and renal (1.3%) puncture sites, whereas at other puncture sites it ranged from 0 to 0.4%. The incidence of pneumothorax following biopsy of intrapulmonary lesions was 1.6%. Elevated INR, multiple punctures, dual antiplatetelet therapy and hypervascular tumor types in liver biopsies were indentified as risk factors associated with an increased risk of bleeding, irrespective of puncture site. Using the CIRSE classification, which defines an unscheduled prolongation of hospital stay as a serious complication (CIRSE grade 2: <48 h and grade 3: >48 h), the rate of serious complications increased from 0.39% to 0.48% (corresponding to seven additional patients). Overall, ultrasound-guided tumor biopsy represents a safe procedure with low complication risk. The majority of serious complications requiring prompt treatment occur subacutely, within 6-24 hours after biopsy. For biopsies, especially those associated with higher puncture-related risk, a 24-hour observation period represents an appropriate precautionary measure. Regarding radiofrequency ablation, the literature describes improved overall survival and recurrence free survival when radiofrequency ablation is used in addition to systemic therapy in patients with colorectal carcinoma with liver-limited metastases. The purpose of the study „Potential for cure and predictors of long-term survival after radiofrequency ablation for colorectal liver metastases: A 20-years single-center experience “, published in June 2022 in the European Journal of Surgical Oncology, was to assess the potential and predictive factors of long-term survival and cure to optimize patient selection for the application of radiofrequency ablation. The data of 158 patients who underwent ablation of liver metastases after receiving systemic therapy were retrospectively analyzed. In addition, overall survival and recurrence-free survival were correlated with the molecular status of KRAS and BRAF, which has been routinely assessed since 2010. In the presence of no more than three lesions with a maximum tumor size of 3 cm and a favorable response to preceding systemic therapy, the 10-year disease free survival rate was estimated at approximately 15% and was interpreted as a surrogate marker of cure. In the absence of any of these factors, the estimated probability was 0%. A mutated KRAS or BRAF status was identified as a negative prognostic factor, both overall and within this specific patient cohort.
Open Access
Effects of PDAC tumour cell conditioned media on the activational states of dendritic cells
(2026-08-11)
Paul, Tharrun Daniel
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Mayer, Johannes U
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Lauth, Matthias
Pancreatic ductal adenocarcinoma (PDAC) is an exceedingly aggressive cancer distinguished by a markedly immunosuppressive tumour microenvironment. Soluble factors derived from tumours significantly influence the function of immune cells, especially in the myeloid compartment. Type 2 conventional dendritic cells (DC2s) are essential antigen-presenting cells and crucial modulators of adaptive immunity that modulate CD4⁺ T-cell responses; however, their reaction to PDAC-derived signals is inadequately characterised. This study examines the impact of tumour-conditioned media (TCM) on the activation of DC2 and the expression of immune checkpoints, particular focus on programmed death ligand-2 (PD-L2/CD273). Bone marrow-derived dendritic cell cultures were initially optimised, revealing that FLT3L preferentially facilitates the generation of a homogeneous DC2 population, while GM-CSF and IL-4 enhance heterogeneity and monocytic skewing. Through this system, DC2s were subjected to TCM derived from various tumour cell lines. TCM derived from PDAC, specifically from KPC5 cell line, significantly upregulated PD-L2 compared toother colorectal tumour line, whereas the expression of PD-L1 was less notably influenced. Additionally heterogenous kras harbouring PDAC TCM had a stronger influence on checkpoint marker expression compared to kras wild type variant. Proteomic analysis demonstrated an enrichment of immunomodulatory factors, such as GM-CSF. Fractionation experiments revealed that the induction of PD-L2 is predominantly influenced by soluble factors rather than components associated with extracellular vesicles. Moreover, the neutralisation of GM-CSF led to a partial decrease in PD-L2 expression, suggesting its role in a larger regulatory framework. DC2s demonstrated simultaneous upregulation of activation markers and checkpoint expression, indicating the emergence of a semi-mature, immunoregulatory phenotype. These findings collectively underscore a tumour secretome-driven mechanism of DC2 reprogramming and imply that PD-L2-mediated regulation may facilitate immune evasion in PDAC.
Open Access
God and governance: religious identity and support for faith-based rule in Nigeria
(Taylor and Francis)
Tuki, Daniel
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Kwari, Hussaini
Despite ongoing debates over religious governance in Nigeria, empirical research on citizens’ attitudes toward its adoption remains scarce. This study addresses that gap by using data from the World Values Survey to examine the relationship between religious affiliation and preferences around religious governance. Our measure is derived from a survey question gauging respondents’ amenability to a political system governed by religious law without political parties or elections. Descriptive analysis reveals that 61% of Nigerians support religious governance. Ordered logit regression analysis indicates that Muslims are more likely than Christians to support such a system. However, disaggregating the data by region reveals a distinct pattern: in the north, Muslims express significantly higher support for religious governance than Christians; in the south, Muslim and Christian attitudes do not differ statistically. The analysis also reveals that northern Muslims show greater support for religious governance than their southern counterparts, while no regional differences are observed among Christians. Taken together, these findings challenge portrayals of Nigerian Muslims as a homogeneous bloc and underscore the importance of regional context in shaping attitudes toward theocracy.
Open Access
Gender and migration aspirations in Nigeria: A comparative study of the states of Edo and Kaduna
(Taylor and Francis)
Tuki, Daniel
This study examines the relationship between gender and migration aspirations in the Nigerian states of Kaduna and Edo, located in the northern and southern regions, respectively. Regression analysis reveals that respondents in Edo are more likely than those in Kaduna to report higher levels of migration aspirations and concrete plans to emigrate. Disaggregated data reveal a notable pattern: women in Kaduna, especially those who are married, are less likely than men to report high migration aspirations or emigration plans. These results may be explained by the salience of gender norms: women are expected to be homemakers, which attenuates their migration aspirations. By contrast, women in Edo do not differ from men in terms of migration aspirations; they are, however, less likely than men to have made actual emigration plans. The relationship between gender and emigration plans is also moderated by marital status and household wealth in Edo. Specifically, women from wealthy households report a lower probability of making emigration plans compared to men from similar households, while the negative impact of marriage on migration aspirations is less pronounced for women than for men.