Refine
Year of publication
- 2021 (76) (remove)
Document Type
- Article (40)
- Conference Proceeding (21)
- Lecture (8)
- Book (3)
- Part of a Book (3)
- Report (1)
Keywords
- Tissue Engineering (10)
- Biomaterials (6)
- Convection (4)
- Radiative transfer (3)
- wireless sensor network (3)
- Asteroseismology (2)
- Betriebswirtschaftslehre (2)
- COVID-19 (2)
- DC/DC converter (2)
- DC/DC converters (2)
Cross-disciplinary collaborations have become an increasingly important part of science. They are seen as key if we are to find solutions to pressing, global-scale societal challenges, including green technologies, sustainable food production, and drug development. The synergistic and skillful combining of different disciplines can achieve insight beyond current borders and thereby generate novel solutions to complex problems. The combination of methods and data from different fields can achieve more than the sum of the individual parts could do alone.
Initiating and successfully maintaining cross-disciplinary collaborations can be challenging but highly rewarding. In this talk I will focus on the specific challenges associated with cross-disciplinary research, from the perspective of the theoretician in particular. Based on “10 simple rules” (https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1004214) I will describe the key benefits, as well as some possible pitfalls, arising from collaborations between scientists with very different backgrounds.
A permutation can be locally classified according to the four local types: peaks, valleys, double rises and double falls. The corresponding classification of binary increasing trees uses four different types of nodes. Flajolet demonstrated the continued fraction representation of the generating function of local types, using a classical bijection between permutations, binary increasing trees, and suitably defined path diagrams induced by Motzkin paths.
The aim of this article is to extend the notion of local types from permutations to k-Stirling permutations (also known as k-multipermutations). We establish a bijection of these local types to node types of (k+1)-ary increasing trees. We present a branched continued fraction representation of the generating function of these local types through a bijection with path diagrams induced by Łukasiewicz paths, generalizing the results from permutations to arbitrary k-Stirling permutations.
We further show that the generating function of ordinary Stirling permutation has at least three branched continued fraction representations, using correspondences between non-standard increasing trees, k-Stirling permutations and path diagrams.
Stellar evolution models with entropy-calibrated mixing-length parameter: application to red giants
(2021)
Detection, quantification and monitoring of virus – host cell interactions are of great importance when evaluating the safety of pharmaceutical products. With the wide usage of viral based vector systems in combination with mammalian cell lines for the production of biopharmaceuticals, the presence of replication competent viral particles needs to be avoided and potential hazards carefully assessed. Consequently, regulatory agencies recommend viral clearance studies using plaque assays or TCID50 assays to evaluate the efficiency of the production process in removing viruses. While plaque assays provide reliable information on the presence of viral contaminations, they are still tedious to perform and can take up to two weeks to finish. To overcome some of these limitations, we have automated, miniaturized and integrated the dual cell culture bioassay into a common lab-on-a-chip platform containing embedded electrical sensor arrays to enrich and detect infectious viruses. Results of our microfluidic single step assay show that a significant reduction in assay time down to 3 to 4 days can be achieved using simultaneous cell-based viral amplification, release and detection of cytopathic effects in a target cell line. We further demonstrate the enhancing effect of continuous fluid flow on infection of PG-4 reporter cells by newly formed and highly active virions by M. dunni cells, thus pointing to the importance of physical relevant viral–cell interactions.
During mechanical ventilation, a disparity between flow, pressure and volume demands of the patient and the assistance delivered by the mechanical ventilator often occurs. This paper introduces an alternative approach of simulating and evaluating patient–ventilator interactions with high fidelity using the electromechanical lung simulator xPULM™. The xPULM™ approximates respiratory activities of a patient during alternating phases of spontaneous breathing and apnea intervals while connected to a mechanical ventilator. Focusing on different triggering events, volume assist-control (V/A-C) and pressure support ventilation (PSV) modes were chosen to test patient–ventilator interactions. In V/A-C mode, a double-triggering was detected every third breathing cycle, leading to an asynchrony index of 16.67%, which is classified as severe. This asynchrony causes a significant increase of peak inspiratory pressure (7.96 ± 6.38 vs. 11.09 ± 0.49 cmH2O, p < 0.01)) and peak expiratory flow (−25.57 ± 8.93 vs. 32.90 ± 0.54 L/min, p < 0.01) when compared to synchronous phases of the breathing simulation. Additionally, events of premature cycling were observed during PSV mode. In this mode, the peak delivered volume during simulated spontaneous breathing phases increased significantly (917.09 ± 45.74 vs. 468.40 ± 31.79 mL, p < 0.01) compared to apnea phases. Various dynamic clinical situations can be approximated using this approach and thereby could help to identify undesired patient–ventilation interactions in the future. Rapidly manufactured ventilator systems could also be tested using this approach. View Full-Text
Surface effects and turbulent pressure. Assessing the Gas-Γ1 and Reduced-Γ1 empirical models.
(2021)
In this work, the field of a gravitational shockwave generated by a massless point-like particle is calculated at the event horizon of a stationary Kerr–Newman black hole. Using the geometric framework of generalized Kerr–Schild deformations in combination with the spin-coefficient formalism of Newman and Penrose, it is shown that the field equations of the theory, at the event horizon of the black hole, can be reduced to a single linear ordinary differential equation for the so-called profile function of the geometry. This differential relation is solved exactly. Based on the results obtained, a physical interpretation is given for the found shockwave spacetime, and it is clarified how these results lead back to those of previous works on the subject, which deal with the much simpler cases of gravitational shockwaves in static black hole backgrounds.
Open Data Projects
(2021)