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Article ; Online: Chemodynamic therapy agents Cu(II) complexes of quinoline derivatives induced ER stress and mitochondria-mediated apoptosis in SK-OV-3 cells.

Shen, Wen-Ying / Jia, Chun-Peng / Mo, An-Na / Liang, Hong / Chen, Zhen-Feng

2021 Volume 223, Page(s) 113636

Abstract: Three Cu(II) complexes of quinoline derivatives as cancer chemodynamic therapy agents were synthesized and characterized. These complexes were heavily taken up by cells and reacted with cellular glutathione (GSH) to reduce ... ...

Abstract	Three Cu(II) complexes of quinoline derivatives as cancer chemodynamic therapy agents were synthesized and characterized. These complexes were heavily taken up by cells and reacted with cellular glutathione (GSH) to reduce Cu
MeSH term(s)	Animals ; Antineoplastic Agents/chemical synthesis ; Antineoplastic Agents/chemistry ; Antineoplastic Agents/metabolism ; Antineoplastic Agents/pharmacology ; Apoptosis/drug effects ; Cell Cycle Checkpoints/drug effects ; Cell Line, Tumor ; Coordination Complexes/chemical synthesis ; Coordination Complexes/chemistry ; Coordination Complexes/metabolism ; Coordination Complexes/pharmacology ; Copper/chemistry ; Crystallography, X-Ray ; Drug Screening Assays, Antitumor ; Endoplasmic Reticulum Stress/drug effects ; Glutathione/chemistry ; Humans ; Hydrogen Peroxide/pharmacology ; Mice ; Mitochondria/drug effects ; Mitochondria/metabolism ; Molecular Conformation ; Neoplasms/drug therapy ; Neoplasms/pathology ; Quinolines/chemistry ; Tissue Distribution ; Transplantation, Heterologous
Chemical Substances	Antineoplastic Agents ; Coordination Complexes ; Quinolines ; Copper (789U1901C5) ; Hydrogen Peroxide (BBX060AN9V) ; Glutathione (GAN16C9B8O)
Language	English
Publishing date	2021-06-16
Publishing country	France
Document type	Journal Article
ZDB-ID	188597-2
ISSN	1768-3254 ; 0009-4374 ; 0223-5234
ISSN (online)	1768-3254
ISSN	0009-4374 ; 0223-5234
DOI	10.1016/j.ejmech.2021.113636
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Article ; Online: Slack-based tunable damping leads to a trade-off between robustness and efficiency in legged locomotion.

Mo, An / Izzi, Fabio / Gönen, Emre Cemal / Haeufle, Daniel / Badri-Spröwitz, Alexander

Scientific reports

2023 Volume 13, Issue 1, Page(s) 3290

Abstract: Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few tens of meters per second. If reflex loops deliver sensory information with significant delays, one would expect a ... ...

Abstract	Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few tens of meters per second. If reflex loops deliver sensory information with significant delays, one would expect a destabilizing effect on sensorimotor control. Hence, an alternative explanation describes a hierarchical structure of low-level adaptive mechanics and high-level sensorimotor control to help mitigate the effects of transmission delays. Motivated by the concept of an adaptive mechanism triggering an immediate response, we developed a tunable physical damper system. Our mechanism combines a tendon with adjustable slackness connected to a physical damper. The slack damper allows adjustment of damping force, onset timing, effective stroke, and energy dissipation. We characterize the slack damper mechanism mounted to a legged robot controlled in open-loop mode. The robot hops vertically and planarly over varying terrains and perturbations. During forward hopping, slack-based damping improves faster perturbation recovery (up to 170%) at higher energetic cost (27%). The tunable slack mechanism auto-engages the damper during perturbations, leading to a perturbation-trigger damping, improving robustness at a minimum energetic cost. With the results from the slack damper mechanism, we propose a new functional interpretation of animals' redundant muscle tendons as tunable dampers.
MeSH term(s)	Animals ; Locomotion/physiology ; Tendons ; Muscle, Skeletal/physiology
Language	English
Publishing date	2023-02-25
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-023-30318-3
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Article ; Online: Muscle prestimulation tunes velocity preflex in simulated perturbed hopping.

Izzi, Fabio / Mo, An / Schmitt, Syn / Badri-Spröwitz, Alexander / Haeufle, Daniel F B

Scientific reports

2023 Volume 13, Issue 1, Page(s) 4559

Abstract: Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response-termed "preflex"-mitigates neuro-transmission delays, which are hazardous during fast ... ...

Abstract	Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response-termed "preflex"-mitigates neuro-transmission delays, which are hazardous during fast locomotion due to the short stance duration. While the elastic contribution to preflexes has been studied extensively, the function of fibre viscosity due to the force-velocity relation remains unknown. In this study, we present a novel approach to isolate and quantify the preflex force produced by the force-velocity relation in musculo-skeletal computer simulations. We used our approach to analyse the muscle response to ground-level perturbations in simulated vertical hopping. Our analysis focused on the preflex-phase-the first 30 ms after impact-where neuronal delays render a controlled response impossible. We found that muscle force at impact and dissipated energy increase with perturbation height, helping reject the perturbations. However, the muscle fibres reject only 15% of step-down perturbation energy with constant stimulation. An open-loop rising stimulation, observed in locomotion experiments, amplified the regulatory effects of the muscle fibre's force-velocity relation, resulting in 68% perturbation energy rejection. We conclude that open-loop neuronal tuning of muscle activity around impact allows for adequate feed-forward tuning of muscle fibre viscous capacity, facilitating energy adjustment to unexpected ground-level perturbations.
MeSH term(s)	Musculoskeletal System ; Locomotion/physiology ; Muscle Fibers, Skeletal ; Computer Simulation ; Time Factors ; Muscle Contraction/physiology ; Muscle, Skeletal/physiology
Language	English
Publishing date	2023-03-20
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-023-31179-6
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Book ; Online: Upside down

Pradhan, Nayan Man Singh / Frank, Patrick / Mo, An / Badri-Spröwitz, Alexander

affordable high-performance motion platform

2023

Abstract: Parallel robots are capable of high-speed manipulation and have become essential tools in the industry. The proximal placement of their motors and the low weight of their end effectors make them ideal for generating highly dynamic motion. Therefore, ... ...

Abstract	Parallel robots are capable of high-speed manipulation and have become essential tools in the industry. The proximal placement of their motors and the low weight of their end effectors make them ideal for generating highly dynamic motion. Therefore, parallel robots can be adopted for motion platform designs, as long as end effector loads are low. Traditional motion platforms can be large and powerful to generate multiple g acceleration. However, these designs tend to be expensive and large. Similar but smaller motion platforms feature a small work range with reduced degrees of freedom (DoFs) and a limited payload. Here we seek a medium-sized affordable parallel robot capable of powerful and high-speed 6-DoF motion in a comparably large workspace. This work explores the concept of a quadruped robot flipped upside-down, with the motion platform fixed between its feet. In particular, we exploit the high-power dynamic brushless actuation and the four-leg redundancy when moving the motion platform. We characterize the resulting motion platform by tracking sinusoidal and circular trajectories with varying loads. Dynamic motions in 6 DoFs up to 10 Hz and ~10 mm amplitude are possible when moving a mass of 300 grams. We demonstrate single-axis end-effector translations up to ~20 mm at 10 Hz for higher loads of 1.2 kg. The motion platform can be replicated easily by 3D printing and off-the-shelf components. All motion platform-related hardware and the custom-written software required to replicate are open-source. Comment: For associated videos, see https://youtu.be/thXPA2MYcQw For open-source files, see https://github.com/nayan-pradhan/solo-6dof-motion-platform
Keywords	Computer Science - Robotics
Subject code	629
Publishing date	2023-03-31
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Diaphragm Ankle Actuation for Efficient Series Elastic Legged Robot Hopping

Bolignari, Marco / Mo, An / Fontana, Marco / Badri-Spröwitz, Alexander

2022

Abstract: Robots need lightweight legs for agile locomotion, and intrinsic series elastic compliance has proven to be a major ingredient for energy-efficient locomotion and robust locomotion control. Animals' anatomy and locomotion capabilities emphasize the ... ...

Abstract	Robots need lightweight legs for agile locomotion, and intrinsic series elastic compliance has proven to be a major ingredient for energy-efficient locomotion and robust locomotion control. Animals' anatomy and locomotion capabilities emphasize the importance of that lightweight legs and integrated, compact, series elastically actuated for distal leg joints. But unlike robots, animals achieve series elastic actuation by their muscle-tendon units. So far no designs are available that feature all characteristics of a perfect distal legged locomotion actuator; a low-weight and low-inertia design, with high mechanical efficiency, no stick and sliding friction, low mechanical complexity, high-power output while being easy to mount. Ideally, such an actuator can be controlled directly and without mechanical cross-coupling, for example remotely. With this goal in mind, we propose a low-friction, lightweight Series ELastic Diaphragm distal Actuator (SELDA) which meets many, although not all, of the above requirements. We develop, implement, and characterize a bioinspired robot leg that features a SELDA-actuated foot segment. We compare two leg configurations controlled by a central pattern generator that both feature agile forward hopping. By tuning SELDA's activation timing, we effectively adjust the robot's hopping height by 11% and its forward velocity by 14%, even with comparatively low power injection to the distal joint.
Keywords	Computer Science - Robotics
Subject code	629
Publishing date	2022-03-03
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Effective Viscous Damping Enables Morphological Computation in Legged Locomotion.

Mo, An / Izzi, Fabio / Haeufle, Daniel F B / Badri-Spröwitz, Alexander

Frontiers in robotics and AI

2020 Volume 7, Page(s) 110

Abstract: Muscle models and animal observations suggest that physical damping is beneficial for stabilization. Still, only a few implementations of physical damping exist in compliant robotic legged locomotion. It remains unclear how physical damping can be ... ...

Abstract	Muscle models and animal observations suggest that physical damping is beneficial for stabilization. Still, only a few implementations of physical damping exist in compliant robotic legged locomotion. It remains unclear how physical damping can be exploited for locomotion tasks, while its advantages as sensor-free, adaptive force- and negative work-producing actuators are promising. In a simplified numerical leg model, we studied the energy dissipation from viscous and Coulomb damping during vertical drops with ground-level perturbations. A parallel spring- damper is engaged between touch-down and mid-stance, and its damper auto-decouples from mid-stance to takeoff. Our simulations indicate that an adjustable and viscous damper is desired. In hardware we explored effective viscous damping and adjustability, and quantified the dissipated energy. We tested two mechanical, leg-mounted damping mechanisms: a commercial hydraulic damper, and a custom-made pneumatic damper. The pneumatic damper exploits a rolling diaphragm with an adjustable orifice, minimizing Coulomb damping effects while permitting adjustable resistance. Experimental results show that the leg-mounted, hydraulic damper exhibits the most effective viscous damping. Adjusting the orifice setting did not result in substantial changes of dissipated energy per drop, unlike adjusting the damping parameters in the numerical model. Consequently, we also emphasize the importance of characterizing physical dampers during real legged impacts to evaluate their effectiveness for compliant legged locomotion.
Language	English
Publishing date	2020-08-28
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2781824-X
ISSN	2296-9144 ; 2296-9144
ISSN (online)	2296-9144
ISSN	2296-9144
DOI	10.3389/frobt.2020.00110
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Article ; Online: A Framework for Real-Time Intrusion Response in Software Defined Networking Using Precomputed Graphical Security Models

Taehoon Eom / Jin B. Hong / SeongMo An / Jong Sou Park / Dong Seong Kim

Security and Communication Networks, Vol

2020 Volume 2020

Abstract: Software defined networking (SDN) has been adopted in many application domains as it provides functionalities to dynamically control the network flow more robust and more economical compared to the traditional networks. In order to strengthen the ... ...

Abstract	Software defined networking (SDN) has been adopted in many application domains as it provides functionalities to dynamically control the network flow more robust and more economical compared to the traditional networks. In order to strengthen the security of the SDN against cyber attacks, many security solutions have been proposed. However, those solutions need to be compared in order to optimize the security of the SDN. To assess and evaluate the security of the SDN systematically, one can use graphical security models (e.g., attack graphs and attack trees). However, it is difficult to provide defense against an attack in real time due to their high computational complexity. In this paper, we propose a real-time intrusion response in SDN using precomputation to estimate the likelihood of future attack paths from an ongoing attack. We also take into account various SDN components to conduct a security assessment, which were not available when addressing only the components of an existing network. Our experimental analysis shows that we are able to estimate possible attack paths of an ongoing attack to mitigate it in real time, as well as showing the security metrics that depend on the flow table, including the SDN component. Hence, the proposed approach can be used to provide effective real-time mitigation solutions for securing SDN.
Keywords	Technology (General) ; T1-995 ; Science (General) ; Q1-390
Subject code	303
Language	English
Publishing date	2020-01-01T00:00:00Z
Publisher	Hindawi-Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The complete chloroplast genome sequences of six Hylotelephium species

Sung-Mo An / Bo-Yun Kim / Halam Kang / Ha-Rim Lee / Yoo-Bin Lee / Yoo-Jung Park / Kyeong-Sik Cheon / Kyung-Ah Kim

PLoS ONE, Vol 18, Iss 10, p e

Comparative genomic analysis and phylogenetic relationships.

2023 Volume 0292056

Abstract: To evaluate the phylogenetic relationships between Hylotelephium and Orostachys, and to provide important information for further studies, we analyzed the complete chloroplast genomes of six Hylotelephium species and compared the sequences to those of ... ...

Abstract	To evaluate the phylogenetic relationships between Hylotelephium and Orostachys, and to provide important information for further studies, we analyzed the complete chloroplast genomes of six Hylotelephium species and compared the sequences to those of published chloroplast genomes of congeneric species and species of the closely related genus, Orostachys. The total chloroplast genome length of nineteen species, including the six Hylotelephium species analyzed in this study and the thirteen Hylotelephium and Orostachys species analyzed in previous studies, ranged from 150,369 bp (O. minuta) to 151,739 bp (H. spectabile). Their overall GC contents were almost identical (37.7-37.8%). The chloroplast genomes of the nineteen species contained 113 unique genes comprising 79 protein-coding genes (PCGs), 30 transfer RNA genes (tRNAs), and four ribosomal RNA genes (rRNAs). Among the annotated genes, fourteen genes contained one intron, and two genes contained two introns. The chloroplast genomes of the nineteen Hylotelephium and Orostachys species had identical structures. Additionally, the large single copy (LSC), inverted repeat (IR), and small single copy (SSC) junction regions were conserved in the Hylotelephium and Orostachys species. The nucleotide diversity between the Hylotelephium chloroplast genomes was extremely low in all regions, and only one region showed a high Pi value (>0.03). In all nineteen chloroplast genomes, six regions had a high Pi value (>0.03). The phylogenetic analysis showed that the genus delimitation could not be clearly observed even in this study because Hylotelephium formed a paraphyly with subsect. Orostachys of the genus Orostachys. Additionally, the data supported the taxonomic position of Sedum taqeutii, which was treated as a synonym for H. viridescens in previous studies, as an independent taxon.
Keywords	Medicine ; R ; Science ; Q
Subject code	590
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
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Book ; Online: Multi-segmented Adaptive Feet for Versatile Legged Locomotion in Natural Terrain

Chatterjee, Abhishek / Mo, An / Kiss, Bernadett / Gönen, Emre Cemal / Badri-Spröwitz, Alexander

2022

Abstract: Most legged robots are built with leg structures from serially mounted links and actuators and are controlled through complex controllers and sensor feedback. In comparison, animals developed multi-segment legs, mechanical coupling between joints, and ... ...

Abstract	Most legged robots are built with leg structures from serially mounted links and actuators and are controlled through complex controllers and sensor feedback. In comparison, animals developed multi-segment legs, mechanical coupling between joints, and multi-segmented feet. They run agile over all terrains, arguably with simpler locomotion control. Here we focus on developing foot mechanisms that resist slipping and sinking also in natural terrain. We present first results of multi-segment feet mounted to a bird-inspired robot leg with multi-joint mechanical tendon coupling. Our one- and two-segment, mechanically adaptive feet show increased viable horizontal forces on multiple soft and hard substrates before starting to slip. We also observe that segmented feet reduce sinking on soft substrates compared to ball-feet and cylinder-feet. We report how multi-segmented feet provide a large range of viable centre of pressure points well suited for bipedal robots, but also for quadruped robots on slopes and natural terrain. Our results also offer a functional understanding of segmented feet in animals like ratite birds.
Keywords	Computer Science - Robotics
Subject code	629
Publishing date	2022-09-18
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Biophysical Simulation Reveals the Mechanics of the Avian Lumbosacral Organ

Mo, An / Kamska, Viktoriia / Bribiesca-Contreras, Fernanda / Hauptmann, Janet / Daley, Monica / Badri-Spröwitz, Alexander

2022

Abstract: The lumbosacral organ (LSO) is a lumbosacral spinal canal morphology that is universally and uniquely found in birds. Recent studies suggested an intraspinal mechanosensor function that relies on the compliant motion of soft tissue in the spinal cord ... ...

Abstract	The lumbosacral organ (LSO) is a lumbosacral spinal canal morphology that is universally and uniquely found in birds. Recent studies suggested an intraspinal mechanosensor function that relies on the compliant motion of soft tissue in the spinal cord fluid. It has not yet been possible to observe LSO soft tissue motion in vivo due to limitations of imaging technologies. As an alternative approach, we developed an artificial biophysical model of the LSO, and characterize the dynamic responses of this model when entrained by external motion. The parametric model incorporates morphological and material properties of the LSO. We varied the model's parameters to study the influence of individual features on the system response. We characterized the system in a locomotion simulator, producing vertical oscillations similar to the trunk motions. We show how morphological and material properties effectively shape the system's oscillation characteristics. We conclude that external oscillations could entrain the soft tissue of the intraspinal lumbosacral organ during locomotion, consistent with recently proposed sensing mechanisms. Comment: For supplementary materials, see https://doi.org/10.17617/3.VTHO81
Keywords	Quantitative Biology - Tissues and Organs
Subject code	612
Publishing date	2022-12-22
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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