Article
Cell Biology
Ronel Scheepers, Robyn P. Araujo
Summary: Although cholesterol is necessary for cellular viability and proliferation, excessive cholesterol is toxic. Maintaining cellular cholesterol within tight tolerances is crucial and the regulation is known as Robust Perfect Adaptation (RPA). The specific chemical reaction network structures responsible for robust homeostatic regulation of cellular cholesterol have been unclear. In this study, a mathematical description of cholesterol regulation pathways is provided, revealing the involvement of integral control and antithetic integral control in conferring RPA on cellular cholesterol concentration.
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
(2023)
Article
Multidisciplinary Sciences
Mariana Gomez-Schlavon, Hana El-Samad
Summary: Feedback control is a crucial element in life, regulating biological processes from cells to ecosystems. Understanding and designing feedback control systems with biological molecules requires evaluating the contribution and limitations of feedback control mechanisms in cells. A general framework called CoRa (Control Ratio) is introduced here, which quantifies the contribution of biological feedback control mechanisms to adaptation by comparing them to systems without feedback. CoRa provides a simple and intuitive metric applicable to various biological feedback systems.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Stanislav Anastassov, Maurice Filo, Ching-Hsiang Chang, Mustafa Khammash
Summary: The researchers in this study have found a versatile genetic component called inteins that can be used to implement compact biomolecular integral feedback controllers. They have developed a theoretical foundation and a simplified approach for screening and modeling intein-based controllers. Through genetic engineering and testing, they have demonstrated the exceptional adaptation properties of these controllers and their applicability in various fields.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Yael Steinhart, Irit Nitzan, Jacob Goldenberg, David Mazursky
Summary: Consumers tend to have negative perceptions of service providers that limit their freedom, but when service providers impose physical constraints without apologizing, consumers' evaluations of them may actually be boosted. This effect occurs because consumers perceive these constraints as creating a structured environment, which they inherently value. However, when consumers perceive the constraints as excessively restrictive, the positive effect of physical constraints on evaluations is reversed.
Article
Environmental Sciences
Mark A. Brzezinski, Ivia Closset, Janice L. Jones, Gregory F. de Souza, Colin Maden
Summary: The silicon isotope composition of silicic acid in the deep Arctic Ocean is anomalously heavy compared to other ocean basins. The study shows that the isotope values reflect local processes such as drift waters influence and benthic inputs, as well as overall inflow-outflow similarity. Biological productivity and opal burial play a major role in removing light isotopes entering the Arctic Ocean from rivers.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Engineering, Aerospace
Hyeong-Geun Kim, Hyeonbeom Lee
Summary: This article presents a composite guidance law with a three-stage proportional navigation structure for the simultaneous arrival of multiple missiles. It proposes different navigation constants at each stage to achieve the desired impact time. The proposed law sequentially increases, maintains, and decreases the look angle to satisfy the seeker's field-of-view constraint. The simple PN-based structure of the law provides an exact closed-loop solution and useful information for practical implementation.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2022)
Article
Neurosciences
Patrick A. Cody, Thanos Tzounopoulos
Summary: Neural adaptation allows the brain to efficiently process sensory signals despite changes in background noise. In the auditory pathway, contrast in background sound levels leads to different neural responses, but mean firing-rates in auditory cortex remain unaffected by sound level contrast. The neuromodulatory mechanisms behind these phenomena are still unknown.
JOURNAL OF NEUROSCIENCE
(2022)
Article
Biochemical Research Methods
Priyan Bhattacharya, Karthik Raman, Arun K. Tangirala
Summary: The paper introduces a generic method for designing adaptive protein networks based on systems theory. The authors demonstrate that a protein network with different input-output nodes needs to be at least of third-order in order to provide adaptation, and the necessary design principles for adaptation networks include negative feedback or feed-forward realization.
PLOS COMPUTATIONAL BIOLOGY
(2022)
Article
Automation & Control Systems
Marcelo M. Morato, Tobias Holicki, Carsten W. Scherer
Summary: In this paper, we discuss how to synthesize stabilizing model predictive control (MPC) algorithms based on convexly parameterized integral quadratic constraints (IQCs) using general multipliers. We introduce point-wise IQCs with storage to generate the MPC terminal ingredients, enabling closed-loop stability, strict dissipativity, and optimization feasibility. Our approach offers more flexibility in handling uncertainties and nonlinearities, leading to larger regions of attraction for the synthesized predictive controllers compared to standard methods.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Automation & Control Systems
Lukas Schwenkel, Johannes Koehler, Matthias A. A. Mueller, Frank Allgoewer
Summary: In this work, a tube-based model predictive control scheme is proposed for linear systems subject to state and input constraints and characterized by dynamic integral quadratic constraints (IQCs) under dynamic uncertainties. By extending the framework of ρ-hard IQCs for exponential stability analysis to external inputs, it is proven that the error between the true uncertain system and the nominal prediction model is bounded by an exponentially stable scalar system. In the proposed scheme, the state of the error bounding system is predicted and used as a scaling parameter for the tube size, achieving robust constraint satisfaction and input-to-state stability despite dynamic uncertainties and bounded disturbances. A numerical example demonstrates the reduced conservatism of this IQC approach compared to state-of-the-art robust MPC approaches for dynamic uncertainties.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Robert B. Anderson, Julius A. Marshall, Andrea L'Afflitto
Summary: In classical model reference adaptive control, tuning the adaptive rates to meet competing objectives is crucial. Large adaptive rates ensure rapid convergence of trajectory tracking error to zero, but may lead to actuator saturation and excessive overshoots. Conversely, low adaptive rates may result in unsatisfactory trajectory tracking. The proposed MRAC laws for nonlinear systems address these challenges while guaranteeing performance and effectiveness through barrier Lyapunov functions.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2021)
Article
Engineering, Marine
Mingyu Fu, Tan Zhang, Fuguang Ding, Duansong Wang
Summary: This paper presents a safety-guaranteed adaptive neural motion controller for an underactuated hovercraft, which consists of multiple controllers to address constraints on surge, drift angle, and yaw angular velocity, with neural networks incorporated to handle model uncertainties, demonstrating effective control performance through extensive simulations.
Article
Biochemical Research Methods
James Giammona, Otger Campas
Summary: The correct packing arrangements between cells in early embryonic stages are crucial for the proper development of the organism. Different species show distinct cellular arrangements at the 4-cell stage, and the geometry of the embryo confinement plays a key role in determining these arrangements. Embryonic confinement is essential for establishing the proper cell-cell contacts at very early developmental stages.
PLOS COMPUTATIONAL BIOLOGY
(2021)
Editorial Material
Geosciences, Multidisciplinary
Flavio Lehner, Ed Hawkins, Rowan Sutton, Angeline G. Pendergrass, Frances C. Moore
Summary: Combining new constraints on socio-economic trajectories and climate system's response to emissions can significantly reduce projection uncertainties, providing more accurate information for regional climate adaptation decisions.
Article
Multidisciplinary Sciences
Huan Feng, Aiping Pang, Hongbo Zhou
Summary: This paper presents two control designs (integral resonance control and H infinity control) for the multi-performance integrated control problem of the piezoelectric nanopositioning platform. Simulation results show that the H infinity control strategy has the smallest tracking error compared to other methods, with better robustness to load variations and signal perturbations.
SCIENTIFIC REPORTS
(2022)
Article
Biochemistry & Molecular Biology
Mostafizur Mazumder, Katherine E. Brechun, Yongjoo B. Kim, Stefan A. Hoffmann, Yih Yang Chen, Carrie-Lynn Keiski, Katja M. Arndt, David R. McMillen, G. Andrew Woolley
PROTEIN ENGINEERING DESIGN & SELECTION
(2015)
Article
Biology
Zhe F. Tang, David R. McMillen
JOURNAL OF THEORETICAL BIOLOGY
(2016)
Article
Biotechnology & Applied Microbiology
Sangram Bagh, Mahuya Mandal, Jordan Ang, David R. McMillen
BIOTECHNOLOGY AND BIOENGINEERING
(2011)
Article
Biochemical Research Methods
Marco A. J. Iafolla, Guang Qiang Dong, David R. McMillen
BMC BIOINFORMATICS
(2008)
Article
Biology
Jordan Ang, Sangram Bagh, Brian P. Ingalls, David R. McMillen
JOURNAL OF THEORETICAL BIOLOGY
(2010)
Article
Computer Science, Artificial Intelligence
Sangram Bagh, David R. McMillen
Article
Biochemistry & Molecular Biology
Mostafizur Mazumder, David R. McMillen
NUCLEIC ACIDS RESEARCH
(2014)
Article
Physics, Fluids & Plasmas
Guang Qiang Dong, David R. McMillen
Article
Physics, Fluids & Plasmas
Sangram Bagh, Mostafizur Mazumder, Tharsan Velauthapillai, Vandit Sardana, Guang Qiang Dong, Ashok B. Movva, Len H. Lim, David R. McMillen
Article
Physics, Fluids & Plasmas
Sangram Bagh, Mahuya Mandal, David R. McMillen
Article
Biochemistry & Molecular Biology
Marco A. J. Iafolla, Mostafizur Mazumder, Vandit Sardana, Tharsan Velauthapillai, Karanbir Pannu, David R. McMillen
PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS
(2008)
Review
Biochemical Research Methods
Jordan Ang, Edouard Harris, Brendan J. Hussey, Richard Kil, David R. McMillen
ACS SYNTHETIC BIOLOGY
(2013)
Article
Physics, Fluids & Plasmas
Edouard A. Harris, Eun Jee Koh, Jason Moffat, David R. McMillen
Article
Biophysics
Guang Qiang Dong, Luke Jakobowski, Marco A. J. Iafolla, David R. McMillen
JOURNAL OF BIOLOGICAL PHYSICS
(2007)