Bioinspired Gradient Hydrogel Actuators with Rewritable Patterns and Programmable Shape Deformation

Author(s):  
Kangwei Mo ◽  
Jiehan Lin ◽  
Chunyu Chang ◽  
Peng Wei ◽  
Mei Jin

The botanical world inspires scientists to develop various smart actuators with diverse mechanical motions in response to external stimuli. However, it is challenging to obtain programmable and reversible hydrogel actuators....

2021 ◽  
Vol 9 ◽  
Author(s):  
Qinchao Zheng ◽  
Chenxue Xu ◽  
Zhenlin Jiang ◽  
Min Zhu ◽  
Chen Chen ◽  
...  

Smart actuators refer to integrated devices that are composed of smart and artificial materials, and can provide actuation and dampening capabilities in response to single/multi external stimuli (such as light, heat, magnetism, electricity, humidity, and chemical reactions). Due to their capability of dynamically sensing and interaction with complex surroundings, smart actuators have attracted increasing attention in different application fields, such as artificial muscles, smart textiles, smart sensors, and soft robots. Among these intelligent material, functional hydrogels with fiber structure are of great value in the manufacture of smart actuators. In this review, we summarized the recent advances in stimuli-responsive actuators based on functional materials. We emphasized the important role of functional nano-material-based additives in the preparation of the stimulus response materials, then analyzed the driving response medium, the preparation method, and the performance of different stimuli responses in detail. In addition, some challenges and future prospects of smart actuators are reported.


2021 ◽  
Author(s):  
Baoyi Wu ◽  
Huanhuan Lu ◽  
Xiaoxia Le ◽  
Wei Lu ◽  
Jiawei Zhang ◽  
...  

Shape deformation hydrogels, which are one of the most promising and essential classes of stimuli-responsive polymers, could provide large-scale and reversible deformation under external stimuli.


2013 ◽  
Vol 21 (3) ◽  
pp. 51-61 ◽  
Author(s):  
Mirosław Belej

Abstract The real estate market is an open system, which implies that it is able to exchange signals with other open systems and dynamic systems. The evolution of a market system over time can be described mathematically. If the system's sensitivity threshold to external stimuli is exceeded, it becomes destabilized and moves from a near-balanced state to a state that is far from equilibrium. Those dynamic processes often induce key changes in the system's trajectory of evolution. In search of equilibrium, the system becomes transformed in a process of discontinuous and discrete changes in state variables. The above statement constitutes the research hypothesis in this article. In this study, an attempt was made to develop a mathematical model for visualizing the evolutionary path of the real estate market in the form of continuous changes interrupted by discontinuous changes. The qualitative transformation of the system will be evaluated with the use of the catastrophe theory.


Author(s):  
Gore S. A. ◽  
Gholve S. B. ◽  
Savalsure S. M. ◽  
Ghodake K. B. ◽  
Bhusnure O. G. ◽  
...  

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.


2019 ◽  
Vol 6 (04) ◽  
Author(s):  
JESHIMA KHAN YASIN ◽  
ANIL KUMAR SINGH

Cytoplasmic streaming is one among the vital activities of the living cells. In plants cytolplasmic streaming could clearly be seen in hypocotyls of growing seedlings. To observe cytoplsmic streaming and its correlated intracellular trafficking an investigation was conducted in legumes in comparison with GFP-AtRab75 and 35S::GFP:δTIP tonoplast fusion protein expressing arabidopsis lines. These seedlings were observed under confocal microscopy with different buffer incubation treatments and under different stress conditions. GFP expressing 35S::GFP:δTIP tonoplast lines were looking similar to the control lines and differ under stress conditions. Movement of cytoplasmic invaginations within the tonoplast and cytoplasmic sub vesicle or bulb budding during cytoplasmic streaming was observed in hypocotyls of At-GFP tonoplast plants. We found the cytoplasmic bulbs/ vesicles or sub vesicle formation from the plasma membrane. The streaming speed also depends on the incubation medium in which the specimen was incubated, indicating that the external stimuli as well as internal stimuli can alter the speed of streaming


2020 ◽  
Vol 13 (12) ◽  
pp. e236152
Author(s):  
Naveen Parkash Gupta ◽  
Vinita Verma ◽  
Saurabh Chopra ◽  
Vivek Choudhury

Hyperekplexia is an exaggerated startle to external stimuli associated with a generalised increase in tone seen in neonates with both sporadic and genetic predisposition. This is an uncommon neurological entity that is misdiagnosed as seizure. A 28-days-old infant was admitted to us with characteristic intermittent generalised tonic spasm being treated as a seizure disorder. The infant had characteristic stiffening episode, exaggerated startle and non-habituation on tapping the nose. Hyperekplexia was suspected and confirmed by genetic testing (mutation in the β subunit of glycine was found). Initial improvement was seen with the use of clonazepam, which was not sustained. At the age of 4.5 years, the child is still having neurobehavioural issues like hyperactivity and sensory hyper-responsiveness. Usually, hyperekplexia is benign in nature. We report a case of hyperekplexia with non-sense mutation in the β subunit of GlyR gene having abnormal neurodevelopmental findings at 4.5 years.


Author(s):  
Laura Empson

This book analyses the complex power dynamics and interpersonal politics that lie at the heart of leadership in professional organizations, such as accounting, law, and consulting firms, investment banks, hospitals, and universities. It is based on scholarly research into many of the world’s leading professional organizations across a range of sectors, including interviews with over 500 senior professionals in sixteen countries. Drawing on the latest academic theory to analyse exactly how professionals in organizations come together to create ‘leadership’, it provides new insights into how leaders lead when there is no traditional hierarchy to support them, their own authority is contingent, and they must constantly renegotiate relationships with relatively autonomous professional peers. It explores how leaders persuade highly intelligent, educated, and opinionated professionals to work together; how change happens within professional organizations; and why leaders so often fail. Part I introduces the concept of plural leadership, analysing how leaders establish and maintain their positions within leadership constellations, and the implications for governance in the context of collective or distributed leadership. Part II examines the complex, challenging relationships between professionals as they seek to influence their organizations, including the phenomena of leadership dyads, insecure overachievers, social control, and the rise of the management professional. Part III examines the shifts in the locus of power as professional organizations grow, adapt, and react to external stimuli such as mergers and acquisitions and economic crises. The conclusion identifies the paradoxes inherent in professional organizations and examines the role of leaders in attempting to reconcile them.


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