New Cationic Linear Copolymers and Hydrogels of N-Vinyl Caprolactam and N-Acryloyl-N′-ethyl Piperazine: Synthesis, Reactivity, Influence of External Stimuli on the LCST and Swelling Properties

2012 ◽  
Vol 51 (41) ◽  
pp. 13354-13365 ◽  
Author(s):  
G. Roshan Deen ◽  
Eu Kiat Lim ◽  
Chin Hao Mah ◽  
Kuang Meng Heng
Keyword(s):  
Swelling Properties ◽  
External Stimuli

Preparation of nanocomposite hydrogels with nanoclay: characterization, swelling properties and dye adsorption behavior

2020 ◽  
Vol 65 (2) ◽  
pp. 119-133
Author(s):  
Nesrimne SEDIIKI ◽  
◽  
Djamel ALIOUCHE ◽  
Imene BOUDHENE ◽  
◽  
...  
Keyword(s):  
Dye Adsorption ◽  
Adsorption Behavior ◽  
Swelling Properties ◽  
Nanocomposite Hydrogels

Catastrophe Theory in Explaining Price Dynamics on the Real Estate Market

2013 ◽  
Vol 21 (3) ◽  
pp. 51-61 ◽  
Author(s):  
Mirosław Belej
Keyword(s):  
Real Estate ◽  
Catastrophe Theory ◽  
Open Systems ◽  
Real Estate Market ◽  
Sensitivity Threshold ◽  
State Variables ◽  
The Real ◽  
The Real Estate ◽  
The Real Estate Market ◽  
External Stimuli

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.

Smart Polymers and their Applications: A Review

2017 ◽  
Vol 8 (03) ◽  
Author(s):  
Gore S. A. ◽  
Gholve S. B. ◽  
Savalsure S. M. ◽  
Ghodake K. B. ◽  
Bhusnure O. G. ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Water Soluble ◽  
Solution Temperature ◽  
Smart Polymers ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Water Soluble Polymers ◽  
Commercial Applications ◽  
Stimuli Sensitive ◽  
External Stimuli

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.

Imine Based Self-Healing Hydrogel Triggered by Periodate

2020 ◽  
Author(s):  
Alexis Wolfel ◽  
Cecilia Inés Alvarez Igarzabal ◽  
Marcelo Ricardo Romero
Keyword(s):  
Functional Groups ◽  
Time Window ◽  
Crosslinking Reaction ◽  
Self Healing ◽  
Swelling Properties ◽  
Covalent Bonds ◽  
Smart Systems ◽  
Primary Amino ◽  
Vicinal Diols ◽  
Aldehyde Groups

<p>Design of materials with novel sensitivities and smart behaviour is important for the development of smart systems with automated responsiveness. We have recently reported the synthesis of hydrogels, cross-linked by <i>N,N'</i>-diallyltartardiamide (DAT). The covalent DAT-crosslinking points have vicinal diols which can be easily cleaved with periodate, generating valuable a-oxo-aldehyde functional groups, useful for further chemical modification. Based on those findings, we envisioned that a self-healable hydrogel could be obtained by incorporation of primary amino functional groups, from <a>2-aminoethyl methacrylate </a>hydrochloride (AEMA), coexisting with DAT into the same network. The a-oxo-aldehyde groups generated after the reaction with periodate would arise in the immediate environment of amine groups to form imine cross-links. For this purpose, DAT-crosslinked hydrogels were synthesized and carefully characterized. The cleavage of DAT-crosslinks with periodate promoted changes in the mechanical and swelling properties of the materials. As expected, a self-healing behavior was observed, based on the spontaneous formation of imine covalent bonds. In addition, we surprisingly found a combination of fast vicinal diols cleavage and a low speed self-crosslinking reaction by imine formation. Consequently, it was found a time-window in which a periodate-treated polymer was obtained in a transient liquid state, which can be exploited to choose the final shape of the material, before automated gelling. The singular properties attained on these hydrogels could be useful for developing sensors, actuators, among other smart systems.</p>

Intracellular trafficking and cytoplasmic streaming under abiotic stress conditions

2019 ◽  
Vol 6 (04) ◽  
Author(s):  
JESHIMA KHAN YASIN ◽  
ANIL KUMAR SINGH
Keyword(s):  
Plasma Membrane ◽  
Abiotic Stress ◽  
Confocal Microscopy ◽  
Fusion Protein ◽  
Intracellular Trafficking ◽  
Cytoplasmic Streaming ◽  
Living Cells ◽  
Stress Conditions ◽  
Vesicle Formation ◽  
External Stimuli

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

Abnormal neurodevelopment outcome in case of neonatal hyperekplexia secondary to missense mutation in GLRB gene

2020 ◽  
Vol 13 (12) ◽  
pp. e236152
Author(s):  
Naveen Parkash Gupta ◽  
Vinita Verma ◽  
Saurabh Chopra ◽  
Vivek Choudhury
Keyword(s):  
Genetic Testing ◽  
Missense Mutation ◽  
Genetic Predisposition ◽  
Seizure Disorder ◽  
Β Subunit ◽  
Tonic Spasm ◽  
Initial Improvement ◽  
External Stimuli ◽  
Neurodevelopment Outcome

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.

Leading Professionals

2017 ◽  
Author(s):  
Laura Empson
Keyword(s):  
Mergers And Acquisitions ◽  
Distributed Leadership ◽  
Investment Banks ◽  
Professional Organizations ◽  
Power Dynamics ◽  
Consulting Firms ◽  
Complex Power ◽  
Plural Leadership ◽  
External Stimuli

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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