877 results on '"Niehoff P"'
Search Results
2. Gyroscope-Assisted CT-Guided Puncture Improves Accuracy and Hit Rate Compared with Free-Hand Puncture: A Phantom Study
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Saeed, Saher, Niehoff, Julius Henning, Boriesosdick, Jan, Michael, Arwed, Schönbeck, Denise, Wöltjen, Matthias Michael, Haag, Nina P., Mönninghoff, Christoph, Borggrefe, Jan, and Kroeger, Jan Robert
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- 2024
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3. The risk of second malignancies following prostate cancer radiotherapy in the era of conformal radiotherapy: a statement of the Prostate Cancer Working Group of the German Society of Radiation Oncology (DEGRO)
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Zamboglou, C., Aebersold, D. M., Albrecht, C., Boehmer, D., Ganswindt, U., Schmidt-Hegemann, N.-S., Hoecht, S., Hölscher, T., Koerber, S. A., Mueller, A.-C., Niehoff, P., Peeken, J. C., Pinkawa, M., Polat, B., Spohn, S. K. B., Wolf, F., Zips, D., and Wiegel, T.
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- 2024
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4. Gewebebiomechanik: Charakterisierung von Bindegewebe: Cluster Gewebebiomechanik
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Seitz, Andreas Martin and Niehoff, Anja
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- 2024
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5. Biochemical, Biomarker, and Behavioral Characterization of the GrnR493X Mouse Model of Frontotemporal Dementia
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Smith, Denise M., Aggarwal, Geetika, Niehoff, Michael L., Jones, Spencer A., Banerjee, Subhashis, Farr, Susan A., and Nguyen, Andrew D.
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- 2024
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6. Imaging of intracranial hemorrhage in photon counting computed tomography using virtual monoenergetic images
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Schoenbeck, Denise, Sacha, Alexander, Niehoff, Julius Henning, Moenninghoff, Christoph, Borggrefe, Jan, Horstmeier, Sebastian, Surov, Alexey, Shahzadi, Iram, Knappe, Ulrich, Kroeger, Jan Robert, and Michael, Arwed Elias
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- 2024
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7. Short‐term mortality prediction in acute pulmonary embolism: Radiomics values of skeletal muscle and intramuscular adipose tissue
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Iram Shahzadi, Alex Zwanenburg, Lynn Johann Frohwein, Dominik Schramm, Hans Jonas Meyer, Mattes Hinnerichs, Christoph Moenninghoff, Julius Henning Niehoff, Jan Robert Kroeger, Jan Borggrefe, and Alexey Surov
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acute pulmonary embolism ,computer tomographic pulmonary angiography ,intramuscular adipose tissue ,machine learning ,radiomics ,skeletal musculature ,Diseases of the musculoskeletal system ,RC925-935 ,Human anatomy ,QM1-695 - Abstract
Abstract Background Acute pulmonary embolism (APE) is a potentially life‐threatening disorder, emphasizing the importance of accurate risk stratification and survival prognosis. The exploration of imaging biomarkers that can reflect patient survival holds the potential to further enhance the stratification of APE patients, enabling personalized treatment and early intervention. Therefore, in this study, we develop computed tomography pulmonary angiography (CTPA) radiomic signatures for the prognosis of 7‐ and 30‐day all‐cause mortality in patients with APE. Methods Diagnostic CTPA images from 829 patients with APE were collected. Two hundred thirty‐four features from each skeletal muscle (SM), intramuscular adipose tissue (IMAT) and both tissues combined (SM + IMAT) were calculated at the level of thoracic vertebra 12. Radiomic signatures were derived using 10 times repeated three‐fold cross‐validation on the training data for SM, IMAT and SM + IMAT for predicting 7‐ and 30‐day mortality independently. The performance of the radiomic signatures was then evaluated on held‐out test data and compared with the simplified pulmonary embolism severity index (sPESI) score, a well‐established biomarker for risk stratification in APE. Predictive accuracy was assessed by the area under the receiver operating characteristic curve (AUC) with a 95% confidence interval (CI), sensitivity and specificity. Results The radiomic signatures based on IMAT and a combination of SM and IMAT (SM + IMAT) achieved moderate performance for the prediction of 30‐day mortality on test data (IMAT: AUC = 0.68, 95% CI [0.57–0.78], sensitivity = 0.57, specificity = 0.73; SM + IMAT: AUC = 0.70, 95% CI [0.60–0.79], sensitivity = 0.74, specificity = 0.54). Radiomic signatures developed for predicting 7‐day all‐cause mortality showed overall low performance. The clinical signature, that is, sPESI, achieved slightly better performance in terms of AUC on test data compared with the radiomic signatures for the prediction of both 7‐ and 30‐day mortality on the test data (7 days: AUC = 0.73, 95% CI [0.67–0.79], sensitivity = 0.92, specificity = 0.16; 30 days: AUC = 0.74, 95% CI [0.66–0.82], sensitivity = 0.97, specificity = 0.16). Conclusions We developed and tested radiomic signatures for predicting 7‐ and 30‐day all‐cause mortality in APE using a multicentric retrospective dataset. The present multicentre work shows that radiomics parameters extracted from SM and IMAT can predict 30‐day all‐cause mortality in patients with APE.
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- 2024
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8. Constructive plaquette compilation for the parity architecture
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ter Hoeven, Roeland, Niehoff, Benjamin E., Kale, Sagar Sudhir, and Lechner, Wolfgang
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Quantum Physics - Abstract
Parity compilation is the challenge of laying out the required constraints for the parity mapping in a local way. We present the first constructive compilation algorithm for the parity architecture using plaquettes for arbitrary higher-order optimization problems. This enables adiabatic protocols, where the plaquette layout can natively be implemented, as well as fully parallelized digital circuits. The algorithm builds a rectangular layout of plaquettes, where in each layer of the rectangle at least one constraint is added. The core idea is that each constraint, consisting of any qubits on the boundary of the rectangle and some new qubits, can be decomposed into plaquettes with a deterministic procedure using ancillas. We show how to pick a valid set of constraints and how this decomposition works. We further give ways to optimize the ancilla count and show how to implement optimization problems with additional constraints., Comment: 8 pages, 5 figures
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- 2023
9. Balancing pH and yield: exploring itaconic acid production in Ustilago cynodontis from an economic perspective
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Ernst, Philipp, Saur, Katharina Maria, Kiefel, Robert, Niehoff, Paul-Joachim, Weskott, Ronja, Büchs, Jochen, Jupke, Andreas, and Wierckx, Nick
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- 2024
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10. Impact of an online reference system on the diagnosis of rare or atypical abdominal tumors and lesions
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Woeltjen, Matthias Michael, Niehoff, Julius Henning, Saeed, Saher, Mendorf, Alexander, Roggel, Ruth, Michael, Arwed Elias, Surov, Alexey, Moenninghoff, Christoph, Borggrefe, Jan, and Kroeger, Jan Robert
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- 2024
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11. Motives and modifying factors for giving or rejecting psychiatric diagnoses in general medicine and psychiatry – a qualitative interview study
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Tebartz van Elst, Hannah, Niehoff, Claudia, and Steinhäuser, Jost
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- 2024
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12. Improving selection decisions with mating information by accounting for Mendelian sampling variances looking two generations ahead
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Niehoff, Tobias A. M., ten Napel, Jan, Bijma, Piter, Pook, Torsten, Wientjes, Yvonne C. J., Hegedűs, Bernadett, and Calus, Mario P. L.
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- 2024
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13. Unprecedented insights into extents of biological responses to physical forcing in an Arctic sub-mesoscale filament by combining high-resolution measurement approaches
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Weiß, Josefine Friederike, von Appen, Wilken-Jon, Niehoff, Barbara, Hildebrand, Nicole, Graeve, Martin, Neuhaus, Stefan, Bracher, Astrid, Nöthig, Eva-Maria, and Metfies, Katja
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- 2024
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14. Validation of computational fluid dynamics of shake flask experiments at moderate viscosity by liquid distributions and volumetric power inputs
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Dinter, Carl, Gumprecht, Andreas, Menze, Matthias Alexander, Azizan, Amizon, Niehoff, Paul-Joachim, Hansen, Sven, and Büchs, Jochen
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- 2024
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15. Toenail and serum levels as biomarkers of iron status in pre- and postmenopausal women: correlations and stability over eight-year follow-up
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Von Holle, Ann, O’Brien, Katie M., Sandler, Dale P., Janicek, Robert, Karagas, Margaret R., White, Alexandra J., Niehoff, Nicole M., Levine, Keith E., Jackson, Brian P., and Weinberg, Clarice R.
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- 2024
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16. Prostate cancer and elective nodal radiation therapy for cN0 and pN0—a never ending story?: Recommendations from the prostate cancer expert panel of the German Society of Radiation Oncology (DEGRO)
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Koerber, S. A., Höcht, S., Aebersold, D., Albrecht, C., Boehmer, D., Ganswindt, U., Schmidt-Hegemann, N.-S., Hölscher, T., Mueller, A.-C., Niehoff, P., Peeken, J. C., Pinkawa, M., Polat, B., Spohn, S. K. B., Wolf, F., Zamboglou, C., Zips, D., and Wiegel, T.
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- 2024
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17. Nonenhanced Photon Counting CT of the Head: Impact of the keV Level, Iterative Reconstruction and Calvaria on Image Quality in Monoenergetic Images
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Michael, Arwed Elias, Schoenbeck, Denise, Woeltjen, Matthias Michael, Boriesosdick, Jan, Kroeger, Jan Robert, Moenninghoff, Christoph, Horstmeier, Sebastian, Niehoff, Julius Henning, Kabbasch, Christoph, Goertz, Lukas, and Borggrefe, Jan
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- 2024
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18. Planning Distributed Security Operations Centers in Multi-Cloud Landscapes: A Case Study
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Schmidt, Andreas U., Knudsen, Sven, Niehoff, Tobias, and Schwietz, Klaus
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Computer Science - Cryptography and Security ,K.6.1 ,K.6.5 - Abstract
We present a case study on the strategic planning of a security operations center in a typical, modern, mid-size organization. Against the backdrop of the company's multi-cloud strategy a distributed approach envisioning the involvement of external providers is taken. From a security-centric abstraction of the organizational IT-landscape, a novel strategic planning method for security operation centers is developed with an adaptable relationship matrix as core tool. The method is put to a practical test in modeling different levels of engagement of external providers in the center's operation. It is shown that concrete output, such as a core statement of work for an external provider, can easily be derived.
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- 2023
19. Balancing pH and yield: exploring itaconic acid production in Ustilago cynodontis from an economic perspective
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Philipp Ernst, Katharina Maria Saur, Robert Kiefel, Paul-Joachim Niehoff, Ronja Weskott, Jochen Büchs, Andreas Jupke, and Nick Wierckx
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Ustilago cynodontis ,Itaconic acid ,Low pH fermentations ,Downstream processing ,Techno-economic analysis ,Biotechnology ,TP248.13-248.65 ,Fuel ,TP315-360 - Abstract
Abstract Background Itaconic acid is a promising bio-based building block for the synthesis of polymers, plastics, fibers and other materials. In recent years, Ustilago cynodontis has emerged as an additional itaconate producing non-conventional yeast, mainly due to its high acid tolerance, which significantly reduces saline waste coproduction during fermentation and downstream processing. As a result, this could likely improve the economic viability of the itaconic acid production process with Ustilaginaceae. Results In this study, we characterized a previously engineered itaconate hyper-producing Ustilago cynodontis strain in controlled fed-batch fermentations to determine the minimal and optimal pH for itaconate production. Under optimal fermentation conditions, the hyper-producing strain can achieve the theoretical maximal itaconate yield during the production phase in a fermentation at pH 3.6, but at the expense of considerable base addition. Base consumption is strongly reduced at the pH of 2.8, but at cost of production yield, titer, and rate. A techno-economic analysis based on the entire process demonstrated that savings due to an additional decrease in pH control reagents and saline waste costs cannot compensate the yield loss observed at the highly acidic pH value 2.8. Conclusions Overall, this work provides novel data regarding the balancing of yield, titer, and rate in the context of pH, thereby contributing to a better understanding of the itaconic acid production process with Ustilago cynodontis, especially from an economic perspective.
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- 2024
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20. Impact of an online reference system on the diagnosis of rare or atypical abdominal tumors and lesions
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Matthias Michael Woeltjen, Julius Henning Niehoff, Saher Saeed, Alexander Mendorf, Ruth Roggel, Arwed Elias Michael, Alexey Surov, Christoph Moenninghoff, Jan Borggrefe, and Jan Robert Kroeger
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Computed tomography ,CT ,Online reference system ,ORS ,STATdx ,Diagnostic performance ,Medicine ,Science - Abstract
Abstract The purpose of the present study is to evaluate whether an online reference system (ORS, STATdx Elsevier, Amsterdam, Netherlands) impacts finding the histologically confirmed diagnosis of rare or atypical abdominal tumors and lesions in radiologic imaging. In total, 101 patients with rare tumor entities or lesions and atypical manifestations of common tumors were enrolled retrospectively. Blinded readings were performed by four radiologists with varying levels of experience, who reported on: (a) correct diagnosis (CD), (b) time needed to find the diagnosis, and (c) diagnostic confidence, initially without followed by the assistance of the ORS. The experienced reader (3 years of experience post-residency, CD 49.5%), as well as the advanced reader with 1 year of experience post-residency (CD 43.6%), and a resident with 5 years of experience (CD 46.5%) made the correct diagnosis more frequently compared to the less experienced reader (CD 25.7%). A significant improvement in making the correct diagnosis was only achieved by the advanced reader, the resident with 5 years of experience (CD with ORS 58.4%; p
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- 2024
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21. First release of the Pelagic Size Structure database: global datasets of marine size spectra obtained from plankton imaging devices
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M. Dugenne, M. Corrales-Ugalde, J. Y. Luo, R. Kiko, T. D. O'Brien, J.-O. Irisson, F. Lombard, L. Stemmann, C. Stock, C. R. Anderson, M. Babin, N. Bhairy, S. Bonnet, F. Carlotti, A. Cornils, E. T. Crockford, P. Daniel, C. Desnos, L. Drago, A. Elineau, A. Fischer, N. Grandrémy, P.-L. Grondin, L. Guidi, C. Guieu, H. Hauss, K. Hayashi, J. A. Huggett, L. Jalabert, L. Karp-Boss, K. M. Kenitz, R. M. Kudela, M. Lescot, C. Marec, A. McDonnell, Z. Mériguet, B. Niehoff, M. Noyon, T. Panaïotis, E. Peacock, M. Picheral, E. Riquier, C. Roesler, J.-B. Romagnan, H. M. Sosik, G. Spencer, J. Taucher, C. Tilliette, and M. Vilain
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
In marine ecosystems, most physiological, ecological, or physical processes are size dependent. These include metabolic rates, the uptake of carbon and other nutrients, swimming and sinking velocities, and trophic interactions, which eventually determine the stocks of commercial species, as well as biogeochemical cycles and carbon sequestration. As such, broad-scale observations of plankton size distribution are important indicators of the general functioning and state of pelagic ecosystems under anthropogenic pressures. Here, we present the first global datasets of the Pelagic Size Structure database (PSSdb), generated from plankton imaging devices. This release includes the bulk particle normalized biovolume size spectrum (NBSS) and the bulk particle size distribution (PSD), along with their related parameters (slope, intercept, and R2) measured within the epipelagic layer (0–200 m) by three imaging sensors: the Imaging FlowCytobot (IFCB), the Underwater Vision Profiler (UVP), and benchtop scanners. Collectively, these instruments effectively image organisms and detrital material in the 7–10 000 µm size range. A total of 92 472 IFCB samples, 3068 UVP profiles, and 2411 scans passed our quality control and were standardized to produce consistent instrument-specific size spectra averaged to 1° × 1° latitude and longitude and by year and month. Our instrument-specific datasets span most major ocean basins, except for the IFCB datasets we have ingested, which were exclusively collected in northern latitudes, and cover decadal time periods (2013–2022 for IFCB, 2008–2021 for UVP, and 1996–2022 for scanners), allowing for a further assessment of the pelagic size spectrum in space and time. The datasets that constitute PSSdb's first release are available at https://doi.org/10.5281/zenodo.11050013 (Dugenne et al., 2024b). In addition, future updates to these data products can be accessed at https://doi.org/10.5281/zenodo.7998799.
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- 2024
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22. Motives and modifying factors for giving or rejecting psychiatric diagnoses in general medicine and psychiatry – a qualitative interview study
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Hannah Tebartz van Elst, Claudia Niehoff, and Jost Steinhäuser
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Qualitative study ,Psychiatric diagnoses ,General medicine ,Psychiatry ,Clinical reasoning ,RC435-571 - Abstract
Abstract Background There is a discussion among general practitioners and psychiatrists regarding over-diagnosing versus under-reporting of psychiatric diagnoses. A deeper understanding of this topic is relevant for providing reasonable health care and for planning future studies. A crucial factor to understanding this discussion is the difference in the prevalence of a disease in each sector. One way to attain knowledge about such prevalences is the analysis of routine care data of the sector in question. However, diagnosis-related data might be modified by several additional influencing factors. Aims This study aims to explore what kind of motives and modifying factors play a role for or against giving psychiatric diagnoses in psychiatric and general medical settings. Methods Twenty-six semi-structured interviews were conducted with German physicians in the fields of general medicine and psychiatry. Interviews were analysed using content analysis. Results The analysis revealed three major motivational categories for finding a diagnosis: (1) “objective matters” such as “categorisation for research”; (2) “functional and performance-related factors” such as “requirement for medication”, “billing aspects” that go with certain diagnoses or “access to adequate care” and (3) “Individual factors” such as the “personality of a physician”. Similarly, factors emerged that lead to not making psychiatric diagnoses like “fear of stigmatization among patients” or “detrimental insurance status with psychiatric diagnosis”. Additionally participants mentioned other reasons for “not diagnosing a psychiatric diagnosis“, such as “coding of other clinical pictures”. Conclusion The diagnostic process is a complex phenomenon that goes far beyond the identification of medical findings. This insight should be considered when processing and interpreting secondary data for designing health care systems or designing a study.
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- 2024
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23. Improving selection decisions with mating information by accounting for Mendelian sampling variances looking two generations ahead
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Tobias A. M. Niehoff, Jan ten Napel, Piter Bijma, Torsten Pook, Yvonne C. J. Wientjes, Bernadett Hegedűs, and Mario P. L. Calus
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Animal culture ,SF1-1100 ,Genetics ,QH426-470 - Abstract
Abstract Background Breeding programs are judged by the genetic level of animals that are used to disseminate genetic progress. These animals are typically the best ones of the population. To maximise the genetic level of very good animals in the next generation, parents that are more likely to produce top performing offspring need to be selected. The ability of individuals to produce high-performing progeny differs because of differences in their breeding values and gametic variances. Differences in gametic variances among individuals are caused by differences in heterozygosity and linkage. The use of the gametic Mendelian sampling variance has been proposed before, for use in the usefulness criterion or Index5, and in this work, we extend existing approaches by not only considering the gametic Mendelian sampling variance of individuals, but also of their potential offspring. Thus, the criteria developed in this study plan one additional generation ahead. For simplicity, we assumed that the true quantitative trait loci (QTL) effects, genetic map and the haplotypes of all animals are known. Results In this study, we propose a new selection criterion, ExpBVSelGrOff, which describes the genetic level of selected grand-offspring that are produced by selected offspring of a particular mating. We compare our criterion with other published criteria in a stochastic simulation of an ongoing breeding program for 21 generations for proof of concept. ExpBVSelGrOff performed better than all other tested criteria, like the usefulness criterion or Index5 which have been proposed in the literature, without compromising short-term gains. After only five generations, when selection is strong (1%), selection based on ExpBVSelGrOff achieved 5.8% more commercial genetic gain and retained 25% more genetic variance without compromising inbreeding rate compared to selection based only on breeding values. Conclusions Our proposed selection criterion offers a new tool to accelerate genetic progress for contemporary genomic breeding programs. It retains more genetic variance than previously published criteria that plan less far ahead. Considering future gametic Mendelian sampling variances in the selection process also seems promising for maintaining more genetic variance.
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- 2024
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24. Dissipation losses limiting first-order phase transition materials in cryogenic caloric cooling: A case study on all-d-metal Ni(-Co)-Mn-Ti Heusler alloys
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Beckmann, Benedikt, Koch, David, Pfeuffer, Lukas, Gottschall, Tino, Taubel, Andreas, Adabifiroozjaei, Esmaeil, Miroshkina, Olga N., Riegg, Stefan, Niehoff, Timo, Kani, Nagaarjhuna A., Gruner, Markus E., Molina-Luna, Leopoldo, Skokov, Konstantin P., and Gutfleisch, Oliver
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Condensed Matter - Materials Science ,Physics - Applied Physics - Abstract
Ni-Mn-based Heusler alloys, in particular all-d-metal Ni(-Co)-Mn-Ti, are highly promising materials for energy-efficient solid-state refrigeration as large multicaloric effects can be achieved across their magnetostructural martensitic transformation. However, no comprehensive study on the crucially important transition entropy change $\Delta s_t$ exists so far for Ni(-Co)-Mn-Ti. Here, we present a systematic study analyzing the composition and temperature dependence of $\Delta s_t$. Our results reveal a substantial structural entropy change contribution of approximately 65 J(kgK)$^{-1}$, which is compensated at lower temperatures by an increasingly negative entropy change associated with the magnetic subsystem. This leads to compensation temperatures $T_{comp}$ of 75 K and 300 K in Ni$_{35}$Co$_{15}$Mn$_{50-y}$Ti$_{y}$ and Ni$_{33}$Co$_{17}$Mn$_{50-y}$Ti$_{y}$, respectively, below which the martensitic transformations are arrested. In addition, we simultaneously measured the responses of the magnetic, structural and electronic subsystems to the temperature- and field-induced martensitic transformation near $T_{comp}$, showing an abnormal increase of hysteresis and consequently dissipation energy at cryogenic temperatures. Simultaneous measurements of magnetization and adiabatic temperature change $\Delta T_{ad}$ in pulsed magnetic fields reveal a change in sign of $\Delta T_{ad}$ and a substantial positive and irreversible $\Delta T_{ad}$ up to 15 K at 15 K as a consequence of increased dissipation losses and decreased heat capacity. Most importantly, this phenomenon is universal, it applies to any first-order material with non-negligible hysteresis and any stimulus, effectively limiting the utilization of their caloric effects for gas liquefaction at cryogenic temperatures.
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- 2023
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25. Low-depth Circuit Implementation of Parity Constraints for Quantum Optimization
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Unger, Josua, Messinger, Anette, Niehoff, Benjamin E., Fellner, Michael, and Lechner, Wolfgang
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Quantum Physics - Abstract
We present a construction for circuits with low gate count and depth, implementing three- and four-body Pauli-Z product operators as they appear in the form of plaquette-shaped constraints in QAOA when using the parity mapping. The circuits can be implemented on any quantum device with nearest-neighbor connectivity on a square-lattice, using only one gate type and one orientation of two-qubit gates at a time. We find an upper bound for the circuit depth which is independent of the system size. The procedure is readily adjustable to hardware-specific restrictions, such as a minimum required spatial distance between simultaneously executed gates, or gates only being simultaneously executable within a subset of all the qubits, for example a single line., Comment: 11 pages, 8 figures
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- 2022
26. Das Forschungsnetzwerk Muskuloskelettale Biomechanik (MSB-Net): Aktuelle Forschungsaktivitäten
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Welke, Bastian, Niehoff, Anja, and Woiczinski, Matthias
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- 2024
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27. Metal artifact reduction in patients with total hip replacements: evaluation of clinical photon counting CT using virtual monoenergetic images
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Schreck, Julian, Laukamp, Kai Roman, Niehoff, Julius Henning, Michael, Arwed Elias, Boriesosdick, Jan, Wöltjen, Matthias Michael, Kröger, Jan Robert, Reimer, Robert P., Grunz, Jan-Peter, Borggrefe, Jan, and Lennartz, Simon
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- 2023
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28. Unprecedented insights into extents of biological responses to physical forcing in an Arctic sub-mesoscale filament by combining high-resolution measurement approaches
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Josefine Friederike Weiß, Wilken-Jon von Appen, Barbara Niehoff, Nicole Hildebrand, Martin Graeve, Stefan Neuhaus, Astrid Bracher, Eva-Maria Nöthig, and Katja Metfies
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Medicine ,Science - Abstract
Abstract In Fram Strait, we combined underway-sampling using the remote-controlled Automated Filtration System for Marine Microbes (AUTOFIM) with CTD-sampling for eDNA analyses, and with high-resolution optical measurements in an unprecedented approach to determine variability in plankton composition in response to physical forcing in a sub-mesoscale filament. We determined plankton composition and biomass near the surface with a horizontal resolution of ~ 2 km, and addressed vertical variability at five selected sites. Inside and near the filament, plankton composition was tightly linked to the hydrological dynamics related to the presence of sea ice. The comprehensive data set indicates that sea-ice melt related stratification near the surface inside the sub-mesoscale filament resulted in increased sequence abundances of sea ice-associated diatoms and zooplankton near the surface. In analogy to the physical data set, the underway eDNA data, complemented with highly sampled phytoplankton pigment data suggest a corridor of 7 km along the filament with enhanced photosynthetic biomass and sequence abundances of sea-ice associated plankton. Thus, based on our data we extrapolated an area of 350 km2 in Fram Strait with enhanced plankton abundances, possibly leading to enhanced POC export in an area that is around a magnitude larger than the visible streak of sea-ice.
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- 2024
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29. Validation of computational fluid dynamics of shake flask experiments at moderate viscosity by liquid distributions and volumetric power inputs
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Carl Dinter, Andreas Gumprecht, Matthias Alexander Menze, Amizon Azizan, Paul-Joachim Niehoff, Sven Hansen, and Jochen Büchs
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Medicine ,Science - Abstract
Abstract Computational fluid dynamics (CFD) has recently become a pivotal tool in the design and scale-up of bioprocesses. While CFD has been extensively utilized for stirred tank reactors (STRs), there exists a relatively limited body of literature focusing on CFD applications for shake flasks, almost exclusively concentrated on fluids at waterlike viscosity. The importance of CFD model validation cannot be overstated. While techniques to elucidate the internal flow field are necessary for model validation in STRs, the liquid distribution, caused by the orbital shaking motion of shake flasks, can be exploited for model validation. An OpenFOAM CFD model for shake flasks has been established. Calculated liquid distributions were compared to suitable, previously published experimental data. Across a broad range of shaking conditions, at waterlike and moderate viscosity (16.7 mPa∙s), the CFD model's liquid distributions align excellently with the experimental data, in terms of overall shape and position of the liquid relative to the direction of the centrifugal force. Additionally, the CFD model was used to calculate the volumetric power input, based on the energy dissipation. Depending on the shaking conditions, the computed volumetric power inputs range from 0.1 to 7 kW/m3 and differed on average by 0.01 kW/m3 from measured literature data.
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- 2024
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30. EMILIN1 deficiency causes arterial tortuosity with osteopenia and connects impaired elastogenesis with defective collagen fibrillogenesis.
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Adamo, Christin S, Beyens, Aude, Schiavinato, Alvise, Keene, Douglas R, Tufa, Sara F, Mörgelin, Matthias, Brinckmann, Jürgen, Sasaki, Takako, Niehoff, Anja, Dreiner, Maren, Pottie, Lore, Muiño-Mosquera, Laura, Gulec, Elif Yilmaz, Gezdirici, Alper, Braghetta, Paola, Bonaldo, Paolo, Wagener, Raimund, Paulsson, Mats, Bornaun, Helen, De Rycke, Riet, De Bruyne, Michiel, Baeke, Femke, Devine, Walter P, Gangaram, Balram, Tam, Allison, Balasubramanian, Meena, Ellard, Sian, Moore, Sandra, Symoens, Sofie, Shen, Joseph, Cole, Stacey, Schwarze, Ulrike, Holmes, Kathryn W, Hayflick, Susan J, Wiszniewski, Wojciech, Nampoothiri, Sheela, Davis, Elaine C, Sakai, Lynn Y, Sengle, Gerhard, and Callewaert, Bert
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Animals ,Humans ,Mice ,Bone Diseases ,Metabolic ,Cutis Laxa ,Collagen ,Elastin ,Extracellular Matrix Proteins ,EFEMP2 ,EMILIN1 ,LOX ,aortic aneurysm ,arterial tortuosity ,collagen ,cutis laxa ,elastic fiber ,extracellular matrix ,fracture ,Rare Diseases ,Pediatric ,Congenital Structural Anomalies ,1.1 Normal biological development and functioning ,2.1 Biological and endogenous factors ,Underpinning research ,Aetiology ,Biological Sciences ,Medical and Health Sciences ,Genetics & Heredity - Abstract
EMILIN1 (elastin-microfibril-interface-located-protein-1) is a structural component of the elastic fiber network and localizes to the interface between the fibrillin microfibril scaffold and the elastin core. How EMILIN1 contributes to connective tissue integrity is not fully understood. Here, we report bi-allelic EMILIN1 loss-of-function variants causative for an entity combining cutis laxa, arterial tortuosity, aneurysm formation, and bone fragility, resembling autosomal-recessive cutis laxa type 1B, due to EFEMP2 (FBLN4) deficiency. In both humans and mice, absence of EMILIN1 impairs EFEMP2 extracellular matrix deposition and LOX activity resulting in impaired elastogenesis, reduced collagen crosslinking, and aberrant growth factor signaling. Collagen fiber ultrastructure and histopathology in EMILIN1- or EFEMP2-deficient skin and aorta corroborate these findings and murine Emilin1-/- femora show abnormal trabecular bone formation and strength. Altogether, EMILIN1 connects elastic fiber network with collagen fibril formation, relevant for both bone and vascular tissue homeostasis.
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- 2022
31. A metabolomics perspective on clorobiocin biosynthesis: discovery of bromobiocin and novel derivatives through LC-MSE-based molecular networking
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Niklas B. M. Janzing, Maurice Niehoff, Wolfram Sander, Christoph H. R. Senges, Sina Schäkermann, and Julia E. Bandow
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metabolomics ,specialized metabolite production ,metabolic network ,halogenase ,antibiotic ,Microbiology ,QR1-502 - Abstract
ABSTRACT Clorobiocin is a well-known, highly effective inhibitor of DNA gyrase belonging to the aminocoumarin antibiotics. To identify potentially novel derivatives of this natural product, we conducted an untargeted investigation of clorobiocin biosynthesis in the known producer Streptomyces roseochromogenes DS 12.976 using LC-MSE, molecular networking, and analysis of fragmentation spectra. Previously undescribed clorobiocin derivatives uncovered in this study include bromobiocin, a variant halogenated with bromine instead of chlorine, hydroxylated clorobiocin, carrying an additional hydroxyl group on its 5-methyl-pyrrole 2-carboxyl moiety, and two other derivatives with modifications on their 3-dimethylallyl 4-hydroxybenzoate moieties. Furthermore, we identified several compounds not previously considered clorobiocin pathway products, which provide new insights into the clorobiocin biosynthetic pathway. By supplementing the medium with different concentrations of potassium bromide, we confirmed that the clorobiocin halogenase can utilize bromine instead of chlorine. The reaction, however, is impeded such that non-halogenated clorobiocin derivatives accumulate. Preliminary assays indicate that the antibacterial activity of bromobioin against Bacillus subtilis and efflux-impaired Escherichia coli matches that of clorobiocin. Our findings emphasize that yet unexplored compounds can be discovered from established strains and biosynthetic gene clusters by means of metabolomics analysis and highlight the utility of LC-MSE-based methods to contribute to unraveling natural product biosynthetic pathways.IMPORTANCEThe aminocoumarin clorobiocin is a well-known gyrase inhibitor produced by the gram-positive bacterium Streptomyces roseochromogenes DS 12.976. To gain a deeper understanding of the biosynthetic pathway of this complex composite of three chemically distinct entities and the product spectrum, we chose a metabolite-centric approach. Employing high-resolution LC-MSE analysis, we investigated the pathway products in extracted culture supernatants of the natural producer. Novel pathway products were identified that expand our understanding of three aspects of the biosynthetic pathway, namely the modification of the noviose, transfer and methylation of the pyrrole 2-carboxyl moiety, and halogenation. For the first time, brominated products were detected. Their levels and the levels of non-halogenated products increased in medium supplemented with KBr. Based on the presented data, we propose that the enzyme promiscuity contributes to a broad product spectrum.
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- 2024
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32. Machine learning techniques to characterize functional traits of plankton from image data
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Orenstein, Eric C, Ayata, Sakina‐Dorothée, Maps, Frédéric, Becker, Érica C, Benedetti, Fabio, Biard, Tristan, Garidel‐Thoron, Thibault, Ellen, Jeffrey S, Ferrario, Filippo, Giering, Sarah LC, Guy‐Haim, Tamar, Hoebeke, Laura, Iversen, Morten Hvitfeldt, Kiørboe, Thomas, Lalonde, Jean‐François, Lana, Arancha, Laviale, Martin, Lombard, Fabien, Lorimer, Tom, Martini, Séverine, Meyer, Albin, Möller, Klas Ove, Niehoff, Barbara, Ohman, Mark D, Pradalier, Cédric, Romagnan, Jean‐Baptiste, Schröder, Simon‐Martin, Sonnet, Virginie, Sosik, Heidi M, Stemmann, Lars S, Stock, Michiel, Terbiyik‐Kurt, Tuba, Valcárcel‐Pérez, Nerea, Vilgrain, Laure, Wacquet, Guillaume, Waite, Anya M, and Irisson, Jean‐Olivier
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Biological Sciences ,Ecology ,Earth Sciences ,Environmental Sciences ,Marine Biology & Hydrobiology ,Biological sciences ,Earth sciences ,Environmental sciences - Abstract
Plankton imaging systems supported by automated classification and analysis have improved ecologists' ability to observe aquatic ecosystems. Today, we are on the cusp of reliably tracking plankton populations with a suite of lab-based and in situ tools, collecting imaging data at unprecedentedly fine spatial and temporal scales. But these data have potential well beyond examining the abundances of different taxa; the individual images themselves contain a wealth of information on functional traits. Here, we outline traits that could be measured from image data, suggest machine learning and computer vision approaches to extract functional trait information from the images, and discuss promising avenues for novel studies. The approaches we discuss are data agnostic and are broadly applicable to imagery of other aquatic or terrestrial organisms.
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- 2022
33. Toenail and serum levels as biomarkers of iron status in pre- and postmenopausal women: correlations and stability over eight-year follow-up
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Ann Von Holle, Katie M. O’Brien, Dale P. Sandler, Robert Janicek, Margaret R. Karagas, Alexandra J. White, Nicole M. Niehoff, Keith E. Levine, Brian P. Jackson, and Clarice R. Weinberg
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Medicine ,Science - Abstract
Abstract Iron status is often assessed in epidemiologic studies, and toenails offer a convenient alternative to serum because of ease of collection, transport, and storage, and the potential to reflect a longer exposure window. Very few studies have examined the correlation between serum and toenail levels for trace metals. Our aim was to compare iron measures using serum and toenails on both a cross-sectional and longitudinal basis. Using a subset of the US-wide prospective Sister Study cohort, we compared toenail iron measures to serum concentrations for iron, ferritin and percent transferrin saturation. Among 146 women who donated both blood and toenails at baseline, a subsample (59%, n = 86) provided specimens about 8 years later. Cross-sectional analyses included nonparametric Spearman’s rank correlations between toenail and serum biomarker levels. We assessed within-woman maintenance of rank across time for the toenail and serum measures and fit mixed effects models to measure change across time in relation to change in menopause status. Spearman correlations at baseline (follow-up) were 0.08 (0.09) for serum iron, 0.08 (0.07) for transferrin saturation, and − 0.09 (− 0.17) for ferritin. The within-woman Spearman correlation for toenail iron between the two time points was higher (0.47, 95% CI 0.30, 0.64) than for serum iron (0.30, 95% CI 0.09, 0.51) and transferrin saturation (0.34, 95% CI 0.15, 0.54), but lower than that for ferritin (0.58, 95% CI 0.43, 0.73). Serum ferritin increased over time while nail iron decreased over time for women who experienced menopause during the 8-years interval. Based on cross-sectional and repeated assessments, our evidence does not support an association between serum biomarkers and toenail iron levels. Toenail iron concentrations did appear to be moderately stable over time but cannot be taken as a proxy for serum iron biomarkers and they may reflect physiologically distinct fates for iron.
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- 2024
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34. Sea-ice decline could keep zooplankton deeper for longer
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Flores, Hauke, Veyssière, Gaëlle, Castellani, Giulia, Wilkinson, Jeremy, Hoppmann, Mario, Karcher, Michael, Valcic, Lovro, Cornils, Astrid, Geoffroy, Maxime, Nicolaus, Marcel, Niehoff, Barbara, Priou, Pierre, Schmidt, Katrin, and Stroeve, Julienne
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- 2023
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35. Survey on brachytherapy training among radiation oncology residents in the German-speaking regions of Europe
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Knoth, Johannes, Konrad, Stefan, Lössl, Kristina, Motisi, Laura, Mäurer, Matthias, Linde, Philipp, Lindel, Katja, Niehoff, Peter, Strnad, Vratislav, Sturdza, Alina, and Corradini, Stefanie
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- 2023
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36. Development of an itaconic acid production process with Ustilaginaceae on alternative feedstocks
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Niehoff, Paul-Joachim, Müller, Waldemar, Pastoors, Johannes, Miebach, Katharina, Ernst, Philipp, Hemmerich, Johannes, Noack, Stephan, Wierckx, Nick, and Büchs, Jochen
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- 2023
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37. Evaluation of the clinical performance of an AI-based application for the automated analysis of chest X-rays
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Niehoff, Julius Henning, Kalaitzidis, Jana, Kroeger, Jan Robert, Schoenbeck, Denise, Borggrefe, Jan, and Michael, Arwed Elias
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- 2023
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38. Scalable set of reversible parity gates for integer factorization
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Lanthaler, Martin, Niehoff, Benjamin E., and Lechner, Wolfgang
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- 2023
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39. Photon counting computed tomography of in-stent-stenosis in a phantom: Optimal virtual monoenergetic imaging in ultra high resolution
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Arwed Elias Michael, Denise Schoenbeck, Matthias Michael Woeltjen, Jan Boriesosdick, Julius Henning Niehoff, Alexey Surov, Jan Borggrefe, Bernhard Schmidt, Christoph Panknin, Tilman Hickethier, David Maintz, Alexander Christian Bunck, Roman Johannes Gertz, and Jan Robert Kroeger
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Computed tomography ,Photon counting computed tomography ,Photon counting detector ,In-stent stenosis ,Stent imaging ,Virtual monoenergetic image ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
1 Abstract: Rationale and objectives: Coronary computed tomography angiography (CCTA) is becoming increasingly important for the diagnostic workup of coronary artery disease, nevertheless, imaging of in-stent stenosis remains challenging. For the first time, spectral imaging in Ultra High Resolution (UHR) is now possible in clinically available photon counting CT. The aim of this work is to determine the optimal virtual monoenergetic image (VMI) for imaging in-stent stenoses in cardiac stents. Materials and methods: 6 stents with inserted hypodense stenoses were scanned in an established phantom in UHR mode. Images were reconstructed with 3 different kernels for spectral data (Qr56, Qr64, Qr72) with varying levels of sharpness. Based on region of interest (ROI) measurements image quality parameters including contrast-to-noise ratio (CNR) were analyzed for all available VMI (40 keV–190 keV). Finally, based on quantitative results and VMI used in clinical routine, a set of VMI was included in a qualitative reading. Results: CNR showed significant variations across different keV levels (p
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- 2024
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40. Parity Quantum Optimization: Compiler
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Ender, Kilian, ter Hoeven, Roeland, Niehoff, Benjamin E., Drieb-Schön, Maike, and Lechner, Wolfgang
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Quantum Physics - Abstract
We introduce parity quantum optimization with the aim of solving optimization problems consisting of arbitrary $k$-body interactions and side conditions using planar quantum chip architectures. The method introduces a decomposition of the problem graph with arbitrary $k$-body terms using generalized closed cycles of a hypergraph. Side conditions of the optimization problem in form of hard constraints can be included as open cycles containing the terms involved in the side conditions. The generalized parity mapping thus circumvents the need to translate optimization problems to a quadratic unconstrained binary optimization problem (QUBO) and allows for the direct encoding of higher-order constrained binary optimization problems (HCBO) on a square lattice and full parallelizability of gates.
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- 2021
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41. Development of an itaconic acid production process with Ustilaginaceae on alternative feedstocks
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Paul-Joachim Niehoff, Waldemar Müller, Johannes Pastoors, Katharina Miebach, Philipp Ernst, Johannes Hemmerich, Stephan Noack, Nick Wierckx, and Jochen Büchs
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Ustilaginaceae ,Ustilago cynodontis ,Ustilago maydis ,Itaconic acid ,Molasses ,Thick juice ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract Background Currently, Aspergillus terreus is used for the industrial production of itaconic acid. Although, alternative feedstock use in fermentations is crucial for cost-efficient and sustainable itaconic acid production, their utilisation with A. terreus most often requires expensive pretreatment. Ustilaginacea are robust alternatives for itaconic acid production, evading the challenges, including the pretreatment of crude feedstocks regarding reduction of manganese concentration, that A. terreus poses. Results In this study, five different Ustilago strains were screened for their growth and production of itaconic acid on defined media. The most promising strains were then used to find a suitable alternative feedstock, based on the local food industry. U. cynodontis ITA Max pH, a highly engineered production strain, was selected to determine the biologically available nitrogen concentration in thick juice and molasses. Based on these findings, thick juice was chosen as feedstock to ensure the necessary nitrogen limitation for itaconic acid production. U. cynodontis ITA Max pH was further characterised regarding osmotolerance and product inhibition and a successful scale-up to a 2 L stirred tank reactor was accomplished. A titer of 106.4 gitaconic acid/L with a theoretical yield of 0.50 gitaconic acid/gsucrose and a space-time yield of 0.72 gitaconic acid/L/h was reached. Conclusions This study demonstrates the utilisation of alternative feedstocks to produce ITA with Ustilaginaceae, without drawbacks in either titer or yield, compared to glucose fermentations.
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- 2023
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42. Von der spätbyzantinischen zur osmanischen topographia sacra in Thrakien: der Derwishkonvent des Qĭzĭl Delü bei Didymoteichon/Dimetoka
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Johannes Niehoff-Panagiotidis
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Topographia sacra ,Derwishkonvent des Qĭzĭl Delü ,Didymoteichon/Dimetoka ,Isaak Sebastokrator ,Johannes Kantakuzenos ,History of Civilization ,CB3-482 - Abstract
In der Fachbibliographie wird der Übergang zwischen der letzten byzantinischen Herrschaft in Nordgriechenland als Bruch beschrieben. Orientalisten beschreiben es als muslimische Eroberung, Byzanzgelehrte als Verlust. Eine gemeinsame Vision beider Positionen ist nicht häufig. Dieses Verfahren vernachlässigt die Tatsache, dass viele Teile Mazedoniens/Thrakiens mehrmals den Besitzer wechselten. Dieser Artikel versucht, osmanische Dokumentation für eine detaillierte Analyse des Territoriums eines der berühmtesten Klöster von Byzanz zu nutzen: dem der Kosmosoteira an der heutigen griechisch-türkischen Grenze in Thrakien (Ferres/Ferecik). Es wurde Mitte des 12. Jahrhunderts von einem berühmten Prinzen der Komneni-Dynastie, Isaac Sebastocrator, dem Sohn von Kaiser Alexius I., gegründet. Im 20. Jahrhundert war es ein Kloster des Bektaschi-Derwisch-Ordens, einer schiitischen Sekte mit Riten, die dem Christentum nahestehen. Was ist in der Zwischenzeit passiert? Wir analysieren die spätbyzantinischen Zeugnisse (Johannes Kantakuzenos) sowie die der Kreuzfahrer im Vergleich zu den ersten osmanischen Dokumenten aus der Region vom Beginn des 15. Jahrhunderts. Das Ergebnis ist überraschend: Das Kloster war bereits in byzantinischer Zeit verlassen und die Sultane übergaben die Gebäude den Sufis des Bektaschi-Ordens. So blieb die mittelalterliche Topographie zumindest teilweise bis weit ins 20. Jahrhundert erhalten.
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- 2023
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43. DeepLOKI- a deep learning based approach to identify zooplankton taxa on high-resolution images from the optical plankton recorder LOKI
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Ellen Oldenburg, Raphael M. Kronberg, Barbara Niehoff, Oliver Ebenhöh, and Ovidiu Popa
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computer vision ,deep learning ,DeepLOKI ,keystone species ,marine and zooplankton ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Zooplankton play a crucial role in the ocean’s ecology, as they form a foundational component in the food chain by consuming phytoplankton or other zooplankton, supporting various marine species and influencing nutrient cycling. The vertical distribution of zooplankton in the ocean is patchy, and its relation to hydrographical conditions cannot be fully deciphered using traditional net casts due to the large depth intervals sampled. The Lightframe On-sight Keyspecies Investigation (LOKI) concentrates zooplankton with a net that leads to a flow-through chamber with a camera taking images. These high-resolution images allow for the determination of zooplankton taxa, often even to genus or species level, and, in the case of copepods, developmental stages. Each cruise produces a substantial volume of images, ideally requiring onboard analysis, which presently consumes a significant amount of time and necessitates internet connectivity to access the EcoTaxa Web service. To enhance the analyses, we developed an AI-based software framework named DeepLOKI, utilizing Deep Transfer Learning with a Convolution Neural Network Backbone. Our DeepLOKI can be applied directly on board. We trained and validated the model on pre-labeled images from four cruises, while images from a fifth cruise were used for testing. The best-performing model, utilizing the self-supervised pre-trained ResNet18 Backbone, achieved a notable average classification accuracy of 83.9%, surpassing the regularly and frequently used method EcoTaxa (default) in this field by a factor of two. In summary, we developed a tool for pre-sorting high-resolution black and white zooplankton images with high accuracy, which will simplify and quicken the final annotation process. In addition, we provide a user-friendly graphical interface for the DeepLOKI framework for efficient and concise processes leading up to the classification stage. Moreover, performing latent space analysis on the self-supervised pre-trained ResNet18 Backbone could prove advantageous in identifying anomalies such as deviations in image parameter settings. This, in turn, enhances the quality control of the data. Our methodology remains agnostic to the specific imaging end system used, such as Loki, UVP, or ZooScan, as long as there is a sufficient amount of appropriately labeled data available to enable effective task performance by our algorithms.
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- 2023
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44. Value-Generating Exploratory Trials in Neurodegenerative Dementias
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Friedman, Lauren G, McKeehan, Nicholas, Hara, Yuko, Cummings, Jeffrey L, Matthews, Dawn C, Zhu, Jian, Mohs, Richard C, Wang, Deli, Hendrix, Suzanne B, Quintana, Melanie, Schneider, Lon S, Grundman, Michael, Dickson, Samuel P, Feldman, Howard H, Jaeger, Judith, Finger, Elizabeth C, Ryan, J Michael, Niehoff, Debra, Dickinson, Susan L-J, Markowitz, Jessica T, Owen, Meriel, Travaglia, Alessio, and Fillit, Howard M
- Subjects
Dementia ,Clinical Research ,Clinical Trials and Supportive Activities ,Acquired Cognitive Impairment ,Aging ,Alzheimer's Disease ,Neurosciences ,Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD) ,Brain Disorders ,Patient Safety ,Neurodegenerative ,8.4 Research design and methodologies (health services) ,Health and social care services research ,Neurological ,Alzheimer Disease ,Clinical Trials as Topic ,Clinical Trials ,Phase I as Topic ,Clinical Trials ,Phase II as Topic ,Drug Development ,Frontotemporal Dementia ,Humans ,Neurodegenerative Diseases ,Outcome Assessment ,Health Care ,Proof of Concept Study ,Research Design ,Treatment Failure ,Treatment Outcome ,Clinical Sciences ,Cognitive Sciences ,Neurology & Neurosurgery - Abstract
Drug development for Alzheimer disease and other neurodegenerative dementias, including frontotemporal dementia, has experienced a long history of phase 2 and phase 3 clinical trials that failed to show efficacy of investigational drugs. Despite differences in clinical and behavioral characteristics, these disorders have shared pathologies and face common challenges in designing early-phase trials that are predictive of late-stage success. Here, we discuss exploratory clinical trials in neurodegenerative dementias. These are generally phase 1b or phase 2a trials that are designed to assess pharmacologic effects and rely on biomarker outcomes, with shorter treatment durations and fewer patients than traditional phase 2 studies. Exploratory trials can establish go/no-go decision points, support proof of concept and dose selection, and terminate drugs that fail to show target engagement with suitable exposure and acceptable safety profiles. Early failure saves valuable resources including opportunity costs. This is especially important for programs in academia and small biotechnology companies but may be applied to high-risk projects in large pharmaceutical companies to achieve proof of concept more rapidly at lower costs than traditional approaches. Exploratory studies in a staged clinical development program may provide promising data to warrant the substantial resources needed to advance compounds through late-stage development. To optimize the design and application of exploratory trials, the Alzheimer's Drug Discovery Foundation and the Association for Frontotemporal Degeneration convened an advisory panel to provide recommendations on outcome measures and statistical considerations for these types of studies and study designs that can improve efficiency in clinical development.
- Published
- 2021
45. Large-$d$ phase transitions in holographic mutual information
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Colin-Ellerin, Sean, Hubeny, Veronika E., Niehoff, Benjamin E., and Sorce, Jonathan
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High Energy Physics - Theory ,General Relativity and Quantum Cosmology - Abstract
In the AdS/CFT correspondence, the entanglement entropy of subregions in the boundary CFT is conjectured to be dual to the area of a bulk extremal surface at leading order in $G_N$ in the holographic limit. Under this dictionary, distantly separated regions in the CFT vacuum state have zero mutual information at leading order, and only attain nonzero mutual information at this order when they lie close enough to develop significant classical and quantum correlations. Previously, the separation at which this phase transition occurs for equal-size ball-shaped regions centered at antipodal points on the boundary was known analytically only in $3$ spacetime dimensions. Inspired by recent explorations of general relativity at large-$d$, we compute the separation at which the phase transition occurs analytically in the limit of infinitely many spacetime dimensions, and find that distant regions cannot develop large correlations without collectively occupying the entire volume of the boundary theory. We interpret this result as illustrating the spatial decoupling of holographic correlations in the large-$d$ limit, and provide intuition for this phenomenon using results from quantum information literature. We also compute the phase transition separation numerically for a range of bulk spacetime dimensions from $4$ to $21$, where analytic results are intractable but numerical results provide insight into the dimension-dependence of holographic correlations. For bulk dimensions above $5$, our exact numerical results are well approximated analytically by working to next-to-leading order in the large-$d$ expansion., Comment: 35 pages, 12 figures
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- 2019
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46. Bulk Reconstruction Beyond the Entanglement Wedge
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Bao, Ning, Chatwin-Davies, Aidan, Niehoff, Benjamin E., and Usatyuk, Mykhaylo
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High Energy Physics - Theory - Abstract
We study the portion of an asymptotically Anti de Sitter geometry's bulk where the metric can be reconstructed, given the areas of minimal 2-surfaces anchored to a fixed boundary subregion. We exhibit situations in which this region can reach parametrically far outside of the entanglement wedge. If the setting is furthermore holographic, so that the bulk geometry is dual to a state in a conformal field theory (CFT), these minimal 2-surface areas can be deduced from the expectation values of operators localized within the boundary subregion. This presents us with an alternative: Either the reduced CFT state encodes significant information about the bulk beyond the entanglement wedge, challenging conventional intuition about holographic subregion duality; or the reduced CFT state fails to contain information about operators whose expectation values give the areas of minimal 2-surfaces anchored within that subregion, challenging conventional intuition about the holographic dictionary., Comment: 6 pages, 1 figure; v3 updated to reflect published version
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- 2019
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47. In vitro effects of imatinib mesylate on radiosensitivity and chemosensitivity of breast cancer cells
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Weigel Marion T, Dahmke Linda, Schem Christian, Bauerschlag Dirk O, Weber Katrin, Niehoff Peter, Bauer Maret, Strauss Alexander, Jonat Walter, Maass Nicolai, and Mundhenke Christoph
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background Breast cancer treatment is based on a combination of adjuvant chemotherapy followed by radiotherapy effecting intracellular signal transduction. With the tyrosine kinase inhibitors new targeted drugs are available. Imatinib mesylate is a selective inhibitor of bcr-abl, PRGFR alpha, beta and c-kit. The purpose of this study was to determine whether Imatinib has an influence on the effectiveness of radiotherapy in breast cancer cell lines and if a combination of imatinib with standard chemotherapy could lead to increased cytoreduction. Methods Colony-forming tests of MCF 7 and MDA MB 231 were used to study differences in cell proliferation under incubation with imatinib and radiation. Changes in expression and phosphorylation of target receptors were detected using western blot. Cell proliferation, migration and apoptosis assays were performed combining imatinib with doxorubicin. Results The combination of imatinib and radiotherapy showed a significantly stronger inhibition of cell proliferation compared to single radiotherapy. Differences in PDGFR expression could not be detected, but receptor phosphorylation was significantly inhibited when treated with imatinib. Combination of imatinib with standard chemotherapy lead to an additive effect on cell growth inhibition compared to single treatment. Conclusions Imatinib treatment combined with radiotherapy leads in breast cancer cell lines to a significant benefit which might be influenced through inhibition of PDGFR phosphorylation. Combining imatinib with chemotherapy enhances cytoreductive effects. Further in vivo studies are needed to evaluate the benefit of Imatinib in combination with radiotherapy and chemotherapy on the treatment of breast cancer.
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- 2010
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48. Scalable set of reversible parity gates for integer factorization
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Martin Lanthaler, Benjamin E. Niehoff, and Wolfgang Lechner
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Astrophysics ,QB460-466 ,Physics ,QC1-999 - Abstract
Abstract Classical microprocessors operate on irreversible gates, that, when combined with AND, half-adder and full-adder operations, execute complex tasks such as multiplication of integers. We introduce parity versions of all components of a multiplication circuit. The parity gates are reversible quantum gates based on the recently introduced parity transformation and build on ground-space encoding of the corresponding gate logic. Using a quantum optimization heuristic, e.g., an adiabatic quantum computing protocol, allows one to quantum mechanically reverse the process of multiplication and thus factor integers, which has applications in cryptography. Our parity approach builds on nearest-neighbor constraints equipped with local fields, able to encode the logic of a binary multiplication circuit in a modular and scalable way.
- Published
- 2023
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49. Evaluation of the clinical performance of an AI-based application for the automated analysis of chest X-rays
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Julius Henning Niehoff, Jana Kalaitzidis, Jan Robert Kroeger, Denise Schoenbeck, Jan Borggrefe, and Arwed Elias Michael
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Medicine ,Science - Abstract
Abstract The AI-Rad Companion Chest X-ray (AI-Rad, Siemens Healthineers) is an artificial-intelligence based application for the analysis of chest X-rays. The purpose of the present study is to evaluate the performance of the AI-Rad. In total, 499 radiographs were retrospectively included. Radiographs were independently evaluated by radiologists and the AI-Rad. Findings indicated by the AI-Rad and findings described in the written report (WR) were compared to the findings of a ground truth reading (consensus decision of two radiologists after assessing additional radiographs and CT scans). The AI-Rad can offer superior sensitivity for the detection of lung lesions (0.83 versus 0.52), consolidations (0.88 versus 0.78) and atelectasis (0.54 versus 0.43) compared to the WR. However, the superior sensitivity is accompanied by higher false-detection-rates. The sensitivity of the AI-Rad for the detection of pleural effusions is lower compared to the WR (0.74 versus 0.88). The negative-predictive-values (NPV) of the AI-Rad for the detection of all pre-defined findings are on a high level and comparable to the WR. The seemingly advantageous high sensitivity of the AI-Rad is partially offset by the disadvantage of a high false-detection-rate. At the current stage of development, therefore, the high NPVs may be the greatest benefit of the AI-Rad giving radiologists the possibility to re-insure their own negative search for pathologies and thus boosting their confidence in their reports.
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- 2023
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50. A Holographic Kaleidoscope for $\mathcal{N}=1^*$
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Bobev, Nikolay, Gautason, Fridrik Freyr, Niehoff, Benjamin E., and van Muiden, Jesse
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High Energy Physics - Theory - Abstract
We study in detail the recently-found family of asymptotically AdS$_5\times S^5$ type IIB supergravity solutions dual to the $\mathcal{N}=1^*$ SYM theory with equal masses. The backgrounds exhibit a naked singularity and are labelled by a dimensionless parameter, $\lambda$, which is interpreted as the ratio of the gaugino condensate and the mass in the dual field theory. When $|\lambda|<1$ we show that the naked singularity is due to a smeared distribution of polarized $(p,q)$ five-branes. For this range of parameters we study the nature of the singularity using probe strings and show that the dual line operators exhibit screening behavior. These features are in line with the physics anticipated in the work of Polchinski-Strassler. For $|\lambda|=1$ the naked singularity has qualitatively different behavior which has no clear brane interpretation. We show that when $\lambda=1$ the singularity can be excised and replaced by a smooth Euclidean supergravity solution with an $S^4$ boundary., Comment: 40 pages, six figures
- Published
- 2019
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