scholarly journals Modeling and simulation of complex dynamic musculoskeletal architectures

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaotian Zhang ◽  
Fan Kiat Chan ◽  
Tejaswin Parthasarathy ◽  
Mattia Gazzola
Keyword(s):  
Neural Control ◽  
Numerical Approach ◽  
Complex Dynamic ◽  
Uncertain Environments ◽  
Cosserat Rods ◽  
Living Organisms ◽  
Dynamic Structures ◽  
Musculoskeletal Systems ◽  
Muscle Connectivity ◽  
Potential Use

Abstract Natural creatures, from fish and cephalopods to snakes and birds, combine neural control, sensory feedback and compliant mechanics to effectively operate across dynamic, uncertain environments. In order to facilitate the understanding of the biophysical mechanisms at play and to streamline their potential use in engineering applications, we present here a versatile numerical approach to the simulation of musculoskeletal architectures. It relies on the assembly of heterogenous, active and passive Cosserat rods into dynamic structures that model bones, tendons, ligaments, fibers and muscle connectivity. We demonstrate its utility in a range of problems involving biological and soft robotic scenarios across scales and environments: from the engineering of millimeter-long bio-hybrid robots to the synthesis and reconstruction of complex musculoskeletal systems. The versatility of this methodology offers a framework to aid forward and inverse bioengineering designs as well as fundamental discovery in the functioning of living organisms.

scholarly journals Self-reproducing catalyst drives repeated phospholipid synthesis and membrane growth

2015 ◽  
Vol 112 (27) ◽  
pp. 8187-8192 ◽  
Author(s):  
Michael D. Hardy ◽  
Jun Yang ◽  
Jangir Selimkhanov ◽  
Christian M. Cole ◽  
Lev S. Tsimring ◽  
...  
Keyword(s):  
Lipid Synthesis ◽  
Building Blocks ◽  
Phospholipid Bilayer ◽  
Phospholipid Synthesis ◽  
Synthetic Membranes ◽  
Design And Synthesis ◽  
Membrane Growth ◽  
Membrane Bound ◽  
Living Organisms ◽  
Dynamic Structures

Cell membranes are dynamic structures found in all living organisms. There have been numerous constructs that model phospholipid membranes. However, unlike natural membranes, these biomimetic systems cannot sustain growth owing to an inability to replenish phospholipid-synthesizing catalysts. Here we report on the design and synthesis of artificial membranes embedded with synthetic, self-reproducing catalysts capable of perpetuating phospholipid bilayer formation. Replacing the complex biochemical pathways used in nature with an autocatalyst that also drives lipid synthesis leads to the continual formation of triazole phospholipids and membrane-bound oligotriazole catalysts from simpler starting materials. In addition to continual phospholipid synthesis and vesicle growth, the synthetic membranes are capable of remodeling their physical composition in response to changes in the environment by preferentially incorporating specific precursors. These results demonstrate that complex membranes capable of indefinite self-synthesis can emerge when supplied with simpler chemical building blocks.

Development and Regulation of Dendritic Spine Synapses

Physiology ◽  
2006 ◽  
Vol 21 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Barbara Calabrese ◽  
Margaret S. Wilson ◽  
Shelley Halpain
Keyword(s):  
Synaptic Transmission ◽  
Dendritic Spines ◽  
Dendritic Spine ◽  
Excitatory Synapses ◽  
Dense Array ◽  
Complex Dynamic ◽  
Neuronal Dendrites ◽  
Spine Abnormalities ◽  
Dynamic Structures ◽  
The Brain

Dendritic spines are small protrusions from neuronal dendrites that form the postsynaptic component of most excitatory synapses in the brain. They play critical roles in synaptic transmission and plasticity. Recent advances in imaging and molecular technologies reveal that spines are complex, dynamic structures that contain a dense array of cytoskeletal, transmembrane, and scaffolding molecules. Several neurological and psychiatric disorders exhibit dendritic spine abnormalities.

The physicochemical properties and distribution of aluminum in the environment, the effect on living organisms, the reduction of its toxic effect

2021 ◽  
Vol 21 (2) ◽  
pp. 25-36
Author(s):  
Victoriia E. Kutai ◽  
Vasiliy Yu. Tsygankov
Keyword(s):  
Water Treatment ◽  
Physicochemical Properties ◽  
Toxic Effect ◽  
Scientific Literature ◽  
Mammary Glands ◽  
Negative Consequences ◽  
Treatment Processes ◽  
Living Organisms ◽  
Musculoskeletal Systems ◽  
Agricultural Food

The review examines the physicochemical properties, distribution in the environment, the effect on living organisms, including toxicity and ecotoxicity, ways of removing aluminum and its compounds from the human and animal organism. Analysis of scientific literature has shown that the widespread use of aluminum in nature, its use in the agricultural, food, cosmetic, aluminum, oil-producing industries, medicine, water treatment processes and other fields of activity leads to an increased intake of this element into the human body. The cumulative nature of the toxic effect of aluminum and its compounds leads to negative consequences for the respiratory, nervous, musculoskeletal systems, and mammary glands.

Prediction of Sloshing Effects Using a Coupled Non-Linear Seakeeping and CFD Code

2013 ◽  
Author(s):  
Worakanok Thanyamanta ◽  
Don Bass ◽  
David Molyneux
Keyword(s):  
Degrees Of Freedom ◽  
Linear Time ◽  
Numerical Approach ◽  
Six Degrees Of Freedom ◽  
Non Linear ◽  
Roll Stabilization ◽  
Tank Geometry ◽  
Fully Coupled ◽  
Potential Use ◽  
Good Agreement

In this paper, a numerical approach for predicting sloshing or roll-stabilization effects is proposed. A 3D non-linear time domain seakeeping code, MOTSIM, was coupled with a commercial CFD code (Flow-3D) and used to predict roll stabilizing performance of an unconventional U-tube tank installed in an oceanographic vessel. The codes were fully coupled and thus provided coupled effects of the external flow field and the motion of the fluid with a free surface inside the anti-roll tank on the ship motion in six degrees of freedom. MOTSIM is a well validated code that has been proven to provide accurate motion prediction for various vessels. The CFD code allows for modeling of complex tank geometry as well as detailed investigation of locations in the tank where severe loads might be experienced. Comparisons of the simulation results with experimental data showed good agreement and significant effects of the anti-roll tank on decreasing the ship’s roll motion. This study also demonstrated the coupled code’s potential use for any type of sloshing problems including the design of roll-stabilization tanks and LNG carriers.

scholarly journals Rotifers in Lake Orta: a potential ecological and evolutionary model system

2016 ◽  
Vol 75 (s2) ◽  
Author(s):  
Stefan Sommer ◽  
Sarma Nandini ◽  
S.S.S. Sarma ◽  
Arpat Ozgul ◽  
Diego Fontaneto
Keyword(s):  
Copper Concentration ◽  
Current Knowledge ◽  
Evolutionary Model ◽  
Recovery Phase ◽  
Resting Stages ◽  
Resurrection Ecology ◽  
History Of ◽  
Chronic Pollution ◽  
Living Organisms ◽  
Potential Use

<p>Lake Orta experienced for a few decades a unique history of chronic pollution, with extreme changes in pH and copper concentration. Currently, the lake has recovered to its almost pristine oligotrophic conditions, but its sediments still preserve the record of all the changes that happened since the establishment of the first polluting factories in the 1920s, through to the liming activities in 1989-1990, and to the recovery phase that is still going on. Here we review the current knowledge for Lake Orta regarding rotifers, a diverse component of the zooplankton of the lake, through studies on living organisms and on their resting stages accumulated in the sediments. We also report a brief review of what is known in general on the effects of changes in pH and copper concentration on rotifers at the population, species and community level, providing expectations for such effects on the rotifers of Lake Orta. Then, we conclude our review with a perspective on the potential use of rotifers hatched from the resting stages in the sediment of Lake Orta with the description of experiments that can be performed in the future in the framework of resurrection ecology, in order to understand the mechanisms of past and future changes in the environment.</p>

scholarly journals A Global Path Planner for Safe Navigation of Autonomous Vehicles in Uncertain Environments

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6103
Author(s):  
Mohammed Alharbi ◽  
Hassan A. Karimi
Keyword(s):  
Autonomous Vehicles ◽  
Dynamic Environments ◽  
Complex Dynamic ◽  
Uncertain Environments ◽  
Sensor Performance ◽  
Safe Navigation ◽  
Path Planner ◽  
Main Barrier ◽  
Safe Path

Autonomous vehicles (AVs) are considered an emerging technology revolution. Planning paths that are safe to drive on contributes greatly to expediting AV adoption. However, the main barrier to this adoption is navigation under sensor uncertainty, with the understanding that there is no perfect sensing solution for all driving environments. In this paper, we propose a global safe path planner that analyzes sensor uncertainty and determines optimal paths. The path planner has two components: sensor analytics and path finder. The sensor analytics component combines the uncertainties of all sensors to evaluate the positioning and navigation performance of an AV at given locations and times. The path finder component then utilizes the acquired sensor performance and creates a weight based on safety for each road segment. The operation and quality of the proposed path finder are demonstrated through simulations. The simulation results reveal that the proposed safe path planner generates paths that significantly improve the navigation safety in complex dynamic environments when compared to the paths generated by conventional approaches.

Complex Dynamic Structures

1981 ◽  
pp. 172-179 ◽  
Author(s):  
B. Hess ◽  
E. M. Chance ◽  
A. R. Curtis ◽  
A. Boiteux
Keyword(s):  
Complex Dynamic ◽  
Dynamic Structures

scholarly journals Principles of neural control and variants of neural network architecture, applied to a complex dynamic system of sea-vessel

2020 ◽  
pp. 18-22
Author(s):  
А.И. Епихин ◽  
Е.В. Хекерт ◽  
М.А. Модина
Keyword(s):  
Neural Network ◽  
Power Plant ◽  
Dynamic System ◽  
Network Architecture ◽  
Neural Control ◽  
Block Diagram ◽  
Control Object ◽  
Network Control ◽  
Complex Dynamic ◽  
Complex Dynamic System

В статье рассматриваются возможности, особенности и перспективы внедрения принципов нейроуправления в контур регулирования, контроля и эксплуатации сложной динамической системы СЭУ-СУДНО. Отдельное внимание уделено базовым характеристикам и принципам нейроуправления. Рассмотрена структурная схема и принцип проектирования нейрорегулятора применительно к данной системе. Кроме того, формализована процедура настройки нейронной сети на моделирование входа/выхода объекта управления, а также принцип выбора архитектуры, определения критериев оптимизации нейронной сети для управления СЭУ-СУДНО. Рассмотрены альтернативные варианты для создания нейросетевой системы управления СЭУ-СУДНО. Отдельное внимание уделено принципам работы системы нейроуправления и ее ключевым характеристикам. Также формализована процедура выбора архитектуры нейронной сети для управления СЭУ-СУДНО и предложено несколько вариантов нейронных сетей для разных исходных параметров. The article discusses the possibilities, features and prospects of introducing the principles of neurocontrol for the regulation, control and operation of a complex dynamic system ship power plant. Special attention is paid to the basic characteristics and principles of neurocontrol. The block diagram and design principle of the neuroregulator in relation to this system are considered. In addition, the procedure for setting up a neural network for modeling the input / output of a control object has been formalized, as well as the principle of choosing an architecture, determining the criteria for optimizing a neural network for controlling the ship power plant-VESSEL. Alternative options for creating a neural network control system the ship power plant-VESSEL are considered. Special attention is paid to the principles of the neurocontrol system and its key characteristics. Also, the procedure for choosing the architecture of a neural network for controlling the ship power plant-VESSEL was formalized and several options for neural networks for different initial parameters were proposed.

scholarly journals Emergence and Evolution of Anthropogenic Landscapes in the Western Mediterranean and Adjacent Atlantic Regions

Fire ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 53 ◽  
Author(s):  
Virginia Iglesias ◽  
Boris Vannière ◽  
Isabelle Jouffroy-Bapicot
Keyword(s):  
Population Expansion ◽  
Western Mediterranean ◽  
Ecological Systems ◽  
Ecosystem Dynamics ◽  
Resource Exploitation ◽  
Pollen Data ◽  
Complex Dynamic ◽  
Anthropogenic Landscapes ◽  
Subsistence Strategies ◽  
Dynamic Structures

Socio-ecological systems are complex, dynamic structures driven by cross-scale interactions between climate, disturbance and subsistence strategies. We synthetize paleoecological data to explore the emergence and evolution of anthropogenic landscapes in southwestern Europe and northern Africa. Specifically, we estimate trends in vegetation and fire, and assess how changes in climate and resource exploitation altered ecosystem dynamics over the last 10,000 years. Pollen data reveal that a complex vegetation mosaic resulted from the conversion of forests into areas suitable for crops, especially after 7000 cal yr BP. Cross-scale analysis shows a progressive decoupling of climate and ecosystem trajectories, which displayed an overall south-to-north time-transgressive pattern consistent with models of population expansion. As human impact increased, so did the use of fire, and after 4000 cal yr BP, levels of biomass burning became homogeneous across the region. This region-wide rise in burning suggests that land-management overrode the effects of climate, fuel and topography. Thus, while increasing the returns and predictability of resources, rapidly-growing communities created a new form of frequent and extensive disturbance that led to profound and persistent changes in the landscape, including shrub encroachment, increased erosion and soil impoverishment.

Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz
Keyword(s):  
Experimental Evidence ◽  
Lipid Membranes ◽  
Energy Supply ◽  
Redox Reactions ◽  
Living Systems ◽  
Asymmetric Distribution ◽  
Conservation Of Energy ◽  
Asymmetrical Distribution ◽  
Energy Conserving ◽  
Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

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