Publikationen an der Fakultät für Mathematik und Naturwissenschaften ab 2019

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Eichfelder, Gabriele; Warnow, Leo
An approximation algorithm for multi-objective optimization problems using a box-coverage. - In: Journal of global optimization, ISSN 1573-2916, Bd. 83 (2022), 2, S. 329-357

For a continuous multi-objective optimization problem, it is usually not a practical approach to compute all its nondominated points because there are infinitely many of them. For this reason, a typical approach is to compute an approximation of the nondominated set. A common technique for this approach is to generate a polyhedron which contains the nondominated set. However, often these approximations are used for further evaluations. For those applications a polyhedron is a structure that is not easy to handle. In this paper, we introduce an approximation with a simpler structure respecting the natural ordering. In particular, we compute a box-coverage of the nondominated set. To do so, we use an approach that, in general, allows us to update not only one but several boxes whenever a new nondominated point is found. The algorithm is guaranteed to stop with a finite number of boxes, each being sufficiently thin.



https://doi.org/10.1007/s10898-021-01109-9
Li, Yangguang; Yan, Chengzhan; Chen, Xuan; Lei, Yong; Ye, Bang-Ce
A highly robust self-supporting nickel nanoarray based on anodic alumina oxide template for determination of dopamine. - In: Sensors and actuators, ISSN 0925-4005, Bd. 350 (2022), 130835

Ratiometric electrochemical sensors can effectively reduce system errors and environmental interference during the detection of a target, affording good sensitivity, reproducibility, and a linear response range. However, traditional proportional electrochemical sensors are limited by the need for complex modifications and the lack of internal reference probes. In this study, we developed a ratiometric electrochemical sensing platform based on nickel nanoarrays as a self-supporting electrode (NiNASSE) by using an anodic alumina oxide template method. An internal reference probe was developed based on nickel nanoparticles (NiNPs) as nickel nanoarrays, presenting a facile modification process and stable redox signal. Furthermore, the highly ordered nanoarray structure expands the specific surface area of NiNASSE and accelerates the electron transfer rate. This new self-supporting proportional electrochemical sensor was successfully applied for the detection of dopamine and displayed good electrocatalytic ability, stability, and feasibility.



https://doi.org/10.1016/j.snb.2021.130835
Zhou, Yujia; Wang, Zidong; Zheng, Chunfang; Fu, Qun; Wu, Minghong; Zhao, Huaping; Lei, Yong
Construction of Co0.85Se@nickel nanopores array hybrid electrode for high-performance asymmetric supercapacitors. - In: Chemical engineering science, Bd. 247 (2022), 117081, insges. 9 S.

Nanostructured current collectors have larger specific surface area and short ion/electron transport path, which are highly desirable for supercapacitors applications. Herein, Co0.85SeNiNPs (Co0.85Se@NiNP) hybrid electrodes are proposed and fabricated, in which NiNP is served as nanostructured current collectors. NiNP has a vertical pore structure and a large specific surface area, which could effectively promote the ion/electron transport efficiency and reduce internal electrical resistance. Compared with Ni foam and Ni foil as current collectors, NiNP enables Co0.85Se@NiNP electrodes show significantly improved specific capacity, rate performance and cycle stability. Finally, an asymmetric supercapacitor device was assembled with Co0.85Se@NiNP hybrid electrode as the binder-free positive electrode and activated carbon (AC) coated on nickel foam as negative electrode. The Co0.85Se@NiNP//AC asymmetric supercapacitors can work in a wide potential window of 0 - 1.6 V with an ultrahigh specific capacity of 182.3 F g^-1 at 1 A g^-1. Most importantly, Co0.85Se@NiNP//AC has a high energy density of 64.81 Wh kg^-1 at 800 W kg^-1 and an outstanding cycle stability of up to 12000 cycles, indicating that Co0.85Se@NiNP electrode has great application potential in supercapacitors.



https://doi.org/10.1016/j.ces.2021.117081
Baier, Robert; Eichfelder, Gabriele; Gerlach, Tobias
Optimality conditions for set optimization using a directional derivative based on generalized Steiner sets. - In: Optimization, ISSN 1029-4945, Bd. 71 (2022), 8, S. 2273-2314

Set-optimization has attracted increasing interest in the last years, as for instance uncertain multiobjective optimization problems lead to such problems with a set-valued objective function. Thereby, from a practical point of view, most of all the so-called set approach is of interest. However, optimality conditions for these problems, for instance using directional derivatives, are still very limited. The key aspect for a useful directional derivative is the definition of a useful set difference for the evaluation of the numerator in the difference quotient. We present here a new set difference which avoids the use of a convex hull and which applies to arbitrary convex sets, and not to strictly convex sets only. The new set difference is based on the new concept of generalized Steiner sets. We introduce the Banach space of generalized Steiner sets as well as anembedding of convex sets in this space using Steiner points.In this Banach space we can easily define a difference and a directional derivative. We use the latter for new optimality conditions for set optimization. Numerical examples illustrate the new concepts.



https://doi.org/10.1080/02331934.2020.1812605
Chen, Li-Yu; Apte, Gurunath; Lindenbauer, Annerose; Frant, Marion; Nguyen, Thi-Huong
Effect of HIT components on the development of breast cancer cells. - In: Life, ISSN 2075-1729, Bd. 11 (2021), 8, 832, S. 1-13

Cancer cells circulating in blood vessels activate platelets, forming a cancer cell encircling platelet cloak which facilitates cancer metastasis. Heparin (H) is frequently used as an anticoagulant in cancer patients but up to 5% of patients have a side effect, heparin-induced thrombocytopenia (HIT) that can be life-threatening. HIT is developed due to a complex interaction among multiple components including heparin, platelet factor 4 (PF4), HIT antibodies, and platelets. However, available information regarding the effect of HIT components on cancers is limited. Here, we investigated the effect of these materials on the mechanical property of breast cancer cells using atomic force microscopy (AFM) while cell spreading was quantified by confocal laser scanning microscopy (CLSM), and cell proliferation rate was determined. Over time, we found a clear effect of each component on cell elasticity and cell spreading. In the absence of platelets, HIT antibodies inhibited cell proliferation but they promoted cell proliferation in the presence of platelets. Our results indicate that HIT complexes influenced the development of breast cancer cells.



https://doi.org/10.3390/life11080832
Wu, Yanjie; Yang, Huaqin; Li, Wei; Mattea, Carlos; Stapf, Siegfried; Zhang, Letian; Ye, Chunlin; Ye, Xiaofeng
Tailored crystalline order of nascent polyethylene from metallocene supported on confined polystyrene. - In: Catalysis today, ISSN 1873-4308, Bd. 368 (2021), S. 272-280

Building the desirable superstructure of polyethylene is one of the important topics for developing high value-added products, which brings potential benefits for society and sustainable development. Crystalline order is the ubiquitous superstructure for enhancing mechanical properties of polymeric materials. In this work, polystyrene copolymers (c-PS) are incorporated into pores of silica through the wet-impregnation procedure of styrene and p-chloromethyl styrene followed by the in-situ free-radical copolymerization. Metallocene catalyst is further immobilized on supported silica. This incorporated c-PS is proved to be coated on the surface of silica pore walls rather than blocking the interparticle channels. The swelling behavior of c-PS inside the pores are performed by pulsed field gradient NMR (PFG-NMR) and thermoporosimetry (TPM-DSC), where a swelling behavior is shown in the toluene owing to the matched solubility parameters between the c-PS and toluene. According to the swelling behavior of c-PS confined in the pores, a compartmentalization is created hindering the formation of chain overlaps and increasing the crystallinity order of nascent polymers. As a result, the nascent polyethylene with a high crystallinity (i.e., bulk crystallinity Xc,DSC=72.9 % and linear crystallinity Xc,WAXD=90.5 %) is synthesized. There is a considerable activity (i.e., 3.8×106 g PE&hahog;(molZr&hahog;h)^-1) at 70˚C. Finally, the particle morphology of the nascent polyethylene is investigated based on the swelling behavior of c-PS.



https://doi.org/10.1016/j.cattod.2019.12.032
Selzer, Silas Aaron; Bauer, Fabian; Bohm, Sebastian; Bretschneider, Peter; Runge, Erich
Physik-geführte NARXnets (PGNARXnets) zur Zeitreihenvorhersage. - In: Proceedings 31. Workshop Computational Intelligence, (2021), S. 235-261

Wagner, Christoph; Gläser, Georg; Sasse, Thomas; Kell, Gerald; Del Galdo, Giovanni
Make some noise: energy-efficient 38 Gbit/s wide-range fully-configurable linear feedback shift register. - In: SMACD / PRIME 2021, (2021), S. 384-387

https://ieeexplore.ieee.org/document/9547997
Hurmach, Vasyl; Platonov, Maxim; Prylutska, Svitlana; Klestova, Zinaida; Cherepanov, Vsevolod; Prylutskyy, Yuriy; Ritter, Uwe
Anticoronavirus activity of water-soluble pristine C60 fullerenes: in vitro and in silico screenings. - In: Basic science and therapy development, (2021), S. 159-172

Introduction: The emergence of a new member of the Coronaviridae family, which caused the 2020 pandemic, requires detailed research on the evolution of coronaviruses, their structure and properties, and interaction with cells. Modern nanobiotechnologies can address the many clinical challenges posed by the COVID-19 pandemic. In particular, they offer new therapeutic approaches using biocompatible nanostructures with “specific” antiviral activity. Therefore, the nanosized spherical-like molecule (0.72 nm in diameter) composed of 60 carbon atoms, C60 fullerene, is of interest in terms of fighting coronaviruses due to its high biological activity. In here, we aim to evaluate the effectiveness of anticoronavirus action of water-soluble pristine C60 fullerene in the model and in vitro systems. As a model, apathogenic for human coronavirus, we used transmissible gastroenteritis virus of swine (TGEV), which we adapted to the BHK-21 cell culture (kidney cells of a newborn Syrian hamster).Methods: The shape and size of the particles present in C60 fullerene aqueous colloidal solution (C60FAS) of given concentration, as well as C60FAS stability (value of zeta potential) were studied using microscopic (STM, scanning tunneling microscopy, and AFM, atomic force microscopy) and spectroscopic (DLS, dynamic light scattering) methods. The cytopathic effect of TGEV was determined with the help of a Leica DM 750 microscope and the degree of monolayer changes in cells was assessed. The microscopy of the viral suspension was performed using a high resolution transmission electron microscope (HRTEM; JEM-1230, Japan). Finally, the search for and design of optimal possible complexes between C60 fullerene and target proteins in the structure of SARS-CoV-2 coronavirus, evaluation of their stability in the simulated cellular environment were performed using molecular dynamics and docking methods.Results: It was found that the maximum allowable cytotoxic concentration of C60 fullerene is 37.5 ± 3.0 [my]g/ml. The investigated C60FAS reduces the titer of coronavirus infectious activity by the value of 2.00 ± 0.08 TCID50/ml. It was shown that C60 fullerene interacts directly with SARS-CoV-2 proteins, such as RdRp (RNA-dependent RNA polymerase) and 3CLpro (3-chymotrypsin-like protease), which is critical for the life cycle of the coronavirus and, thus, inhibits its functional activity. In both cases, C60 fullerene fills the binding pocket and gets stuck there through stacking and steric interactions.Conclusion: Pioneer in vitro study to identify the anticoronavirus activity of water-soluble pristine C60 fullerenes indicates that they are highly promising for further preclinical studies, since a significant inhibition of the infectious activity of swine coronavirus of transmissible gastroenteritis in BHK-21 cell culture was found. According to molecular modeling results, it was shown that C60 fullerene can create the stable complexes with 3CLpro and RdRp proteins of SARS-CoV-2 coronavirus and, thus, suppress its functional activity.



Bouza, Gemayqzel; Quintana, Ernest; Tammer, Christiane
On Clarke's subdifferential of marginal functions. - In: Applied set-valued analysis and optimization, ISSN 2562-7783, Bd. 3 (2021), 3, S. 281-292

In this paper, we derive an upper estimate of the Clarke subdifferential of marginal functions in Banach spaces. The structure of the upper estimate is very similar to other results already obtained in the literature. The novelty lies on the fact that we derive our assertions in general Banach spaces, and avoid the use of the Asplund assumption.



https://doi.org/10.23952/asvao.3.2021.3.03