scholarly journals Propagating wave in a fluid by coherent motion of 2D colloids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Koki Sano ◽  
Xiang Wang ◽  
Zhifang Sun ◽  
Satoshi Aya ◽  
Fumito Araoka ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Ionic Species ◽  
Coherent Motion ◽  
Electrostatic Repulsion ◽  
Strongly Correlated ◽  
Mechanical Motion ◽  
Long Distance ◽  
Van Der Waals Attraction ◽  
Living Organisms ◽  
Uniform Plane

AbstractJust like in living organisms, if precise coherent operation of tiny movable components is possible, one may generate a macroscopic mechanical motion. Here we report that ~1010 pieces of colloidally dispersed nanosheets in aqueous media can be made to operate coherently to generate a propagating macroscopic wave under a non-equilibrium state. The nanosheets are initially forced to adopt a monodomain cofacial geometry with a large and uniform plane-to-plane distance of ~420 nm, where they are strongly correlated by competitive electrostatic repulsion and van der Waals attraction. When the electrostatic repulsion is progressively attenuated by the addition of ionic species, the nanosheets sequentially undergo coherent motions, generating a propagating wave. This elaborate wave in time and space can transport microparticles over a long distance in uniform direction and velocity. The present discovery may provide a general principle for the design of macroscopically movable devices from huge numbers of tiny components.

Development of calix[4]arenes modified at their narrow- and wider-rims as potential metal ions sensor layers for microcantilever sensors: further studies

2021 ◽  
Author(s):  
Paris E. Georghiou ◽  
Shofiur Rahman ◽  
Yousif Assiri ◽  
Gopi Kishore Valluru ◽  
Melita Menelaou ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Computational Study ◽  
Aqueous Media ◽  
Experimental Studies ◽  
Ionic Species ◽  
Alkoxy Group ◽  
Self Assembled Monolayers ◽  
Microcantilever Sensors ◽  
Assembled Monolayers

The development of a microcantilever (MCL) sensing device capable of simultaneously detecting several metal ionic species in aqueous media with low limits of detection requires a variety of sensing layers which are ion-specific. Calix[4]arenes are robust molecules which can be easily modified and have been extensively studied for their ion binding properties. They are also capable of forming self-assembled monolayers (SAMs) onto the gold layers of MCLs and are capable of detecting various metal ions with different anionic counterions in aqueous solutions. In this paper we report on the effect of the alkoxy group in the narrow rim [O-(alkoxycarbonyl)methoxy] substituents of bimodal calix[4]arenes which have been used as metal ion MCL sensing layers, using classical solution state experimental studies. A DFT computational study to compare the experimental results with several metal ions is also reported herein.

Self-Assembly of a β-Sheet Protein Governed by Relief of Electrostatic Repulsion Relative to van der Waals Attraction

2000 ◽  
Vol 1 (4) ◽  
pp. 627-631 ◽  
Author(s):  
Michael R. Caplan ◽  
Peter N. Moore ◽  
Shuguang Zhang ◽  
Roger D. Kamm ◽  
Douglas A. Lauffenburger
Keyword(s):  
Self Assembly ◽  
Van Der Waals ◽  
Electrostatic Repulsion ◽  
Van Der Waals Attraction ◽  
Β Sheet

scholarly journals Particle Adsorption on Hydrogel Surfaces in Aqueous Media due to van der Waals Attraction

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Naoko Sato ◽  
Yurina Aoyama ◽  
Junpei Yamanaka ◽  
Akiko Toyotama ◽  
Tohru Okuzono
Keyword(s):  
Van Der Waals ◽  
Aqueous Media ◽  
Van Der Waals Attraction ◽  
Particle Adsorption

scholarly journals Synthesis and Characterization of Chitosan/Agar/SiO2 Nano Hydrogels For Removal of Amoxicillin and of Naproxen From Pharmaceutical Contaminants

2021 ◽  
Author(s):  
Omid Moradi ◽  
Samira Mhdavi ◽  
Sajjad Sedaghat
Keyword(s):  
Aqueous Media ◽  
Environmental Pollutants ◽  
Chemical Characterization ◽  
Solution Ph ◽  
Physical And Chemical Characterization ◽  
Pharmaceutical Contaminants ◽  
Living Organisms ◽  
Physical And Chemical

Abstract Today, environmental pollutants pose a threat to human societies and all living organisms, which is why they have attracted the attention of environmental researchers. In this study, in order to remove pharmaceutical contaminants Naproxen and Amoxicillin from aqueous media with SiO2 nanoparticles based on Agar and Chitosan was investigated. The study of structural properties, physical and chemical characterization of synthesized nanocomposite was investigated by FTIR, XRD, TEM, FE-SEM, DLS and EDX analyzes. In addition, the role of parameters affecting the removal of pharmaceutical contaminants such as solution pH, contact time, contaminant concentration and temperature were studied. Nanocomposites prepared from Agar and Chitosan showed good performance in absorbing naproxen and amoxicillin. According to the studies performed to remove naproxen, the max adsorption efficiency was obtained at a concentration of 20 mg/l with an absorbent dose of 0.05 g and a pH of 8 and at an optimum temperature of 25 °C and 99% in 15 min. Also, for amoxicillin with nanocomposite prepared with an initial concentration of 20 mg/l and an adsorbent dose of 0.05 g, a time of 10 min, a temperature of 25 °C and a pH of 8, the max removal efficiency of 91.15% was obtained.

Theory of films. - II. The triple-layer film

1973 ◽  
Vol 334 (1596) ◽  
pp. 59-70 ◽  
Keyword(s):  
Lipid Membranes ◽  
Van Der Waals ◽  
Electrostatic Repulsion ◽  
Diffuse Double Layer ◽  
Surface Charges ◽  
Free Standing ◽  
Triple Layer ◽  
Special Cases ◽  
Van Der Waals Attraction ◽  
Zero Frequency

The electrostatic and van der Waals forces and their coupling in aqueous systems with triple-layer geometry is considered. A general problem is formulated which includes the free-standing soap films, the swelling of clay plates and possibly the interaction between lipid membranes, as special cases. This problem is solved for the electrostatic repulsion and the zero-frequency contribution to the van der Waals attraction including the effects of fluctuating surface charges and the relaxation of the diffuse double layer.

Seed and Seedling Biology in Relation to Modelling Vegetation Dynamics Under Global Climate Change

1992 ◽  
Vol 40 (5) ◽  
pp. 599 ◽  
Author(s):  
MR Leishman ◽  
L Hughes ◽  
K French ◽  
D Armstrong ◽  
M Westoby
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Vegetation Dynamics ◽  
Global Climate ◽  
Strongly Correlated ◽  
Long Distance ◽  
Seed Biology ◽  
Functional Types ◽  
Order Of Magnitude ◽  
Dispersal Events

The distribution of many plant species will change with global climate change, depending on their ability to disperse into, and establish in, new communities. Past migrations of species under climate change have been an order of magnitude slower than the rate of predicted climate change for the next century. The limited evidence available suggests that chance long distance dispersal events will be critically important in determining migration rates. The JABOWA-derived gap replacement models and vital attributes/FATE models were examined, and the dispersal and establishment processes necessary to make improved projections of vegetation dynamics under climate change using these models were investigated. The minimum modifications of these models required to incorporate directional migration of species are described. To predict establishment success of species, it was suggested that a more fundamental understanding is needed of how establishment ability under different conditions relates to seed and seedling attributes and how this may be affected by elevated CO2. Finally, an examination was carried out of whether plant functional types based on vegetative attributes (used to model the response of adult plants) are correlated with functional types based on seed and seedling attributes. Available evidence suggests that the two sets of attributes are not strongly correlated; consequently, models of vegetation dynamics will need to incorporate seed biology explicitly.

Interaction between Sulfur(IV) Autoxidation Transients and Bioorganic Compounds

2004 ◽  
Vol 1 (3) ◽  
pp. 137
Author(s):  
Wanda Pasiuk-Bronikowska ◽  
Tadeusz Bronikowski ◽  
Marek Ulejczyk
Keyword(s):  
Sulfur Dioxide ◽  
Organic Compounds ◽  
Chemical Interaction ◽  
Cloud Condensation Nuclei ◽  
Aqueous Media ◽  
Radical Anions ◽  
Destructive Action ◽  
Bioorganic Compounds ◽  
Living Organisms

Environmental Context. Sulfur dioxide has long been known as a source of acidity in precipitation and of cloud condensation nuclei, but more recently it has been shown a source of radicals highly reactive with respect to various organic compounds. These radicals are formed as intermediates wherever sulfur dioxide, oxygen, and water come into contact, such as in a sulfur dioxide polluted environment (tropospheric clouds, surface waters, soil) and in living organisms (lungs, digestive tract). This work focusses on the destructive action of such intermediates upon organic compounds essential for life (such as enzymes and vitamins). Abstract. The oxidation of sulfur dioxide in aqueous media by molecular oxygen is here exploited as a source of sulfoxy radical anions. Experimental evidence is given for the chemical interaction between these radical anions and bioorganic compounds: lysozyme (Lys), haemoglobin (Hb), and cyanocobalamin (vitamin B12). Two opposite effects are described, one leading to the elimination of sulfoxy radical anions and the other resulting in multiplication of the radicals. The former effect is due to lysozyme and haemoglobin, which behave as sulfoxy radical scavengers, whereas the latter is caused by cyanocobalamin, which actively contributes to the formation of these radicals. Possible consequences of the effects for life are briefly discussed with a view to the noxious role of tropospheric sulfur dioxide.

scholarly journals Coherent sea-level fluctuations along the global continental slope

2006 ◽  
Vol 364 (1841) ◽  
pp. 885-901 ◽  
Author(s):  
Chris W Hughes ◽  
Michael P Meredith
Keyword(s):  
Sea Level ◽  
Continental Slope ◽  
Large Scale ◽  
The Arctic ◽  
Strongly Correlated ◽  
Long Distance ◽  
Tropical Regions ◽  
Sea Level Fluctuations ◽  
Wave Modes

Signals in sea-level or, more properly, sub-surface pressure (SSP; sea-level corrected for the inverse barometer effect) are expected to propagate rapidly along the continental slope due to the effect of sloping topography on wave modes, resulting in strongly correlated SSP over long-distances. Observations of such correlations around the Arctic and Antarctic are briefly reviewed, and then extended using satellite altimetry to the rest of the global continental slope. It is shown that such long-distance correlations are common, especially in extra-tropical regions. Simple correlations from altimetry cannot, however, establish the wave speed, or whether waves are responsible for the correlations as opposed to large-scale coherence in the forcing. A case study around South America is used to highlight some of the complications, and is found to strengthen the case for the importance of wave modes in such long-distance SSP coherence, although more detailed in situ data are required to resolve the cause of the correlations.

scholarly journals Lipocalins in arthropod chemical communication

2021 ◽  
Author(s):  
Jiao Zhu ◽  
Alessio Iannucci ◽  
Francesca Romana Dani ◽  
Wolfgang Knoll ◽  
Paolo Pelosi
Keyword(s):  
Chemical Communication ◽  
Binding Proteins ◽  
Aqueous Media ◽  
Vomeronasal Organ ◽  
Odorant Binding Proteins ◽  
Environmental Pressure ◽  
Large Numbers ◽  
Living Organisms ◽  
Odorant Binding ◽  
Chemosensory Organs

Abstract Lipocalins represent one of the most successful superfamilies of proteins. Most of them are extracellular carriers for hydrophobic ligands across aqueous media, but other functions have been reported. They are present in most living organisms including bacteria. In animals they have been identified in mammals, molluscs and arthropods; sequences have also been reported for plants. A sub-group of lipocalins, referred to as odorant-binding proteins (OBPs), mediate chemical communication in mammals by ferrying specific pheromones to the vomeronasal organ. So far, these proteins have not been reported as carriers of semiochemicals in other living organisms; instead chemical communication in arthropods is mediated by other protein families structurally unrelated to lipocalins. A search in the databases has revealed extensive duplication and differentiation of lipocalin genes in some species of insects, crustaceans and chelicerates. Their large numbers, ranging from a handful to few dozens in the same species, their wide divergence, both within and between species, and their expression in chemosensory organs suggest that such expansion may have occurred under environmental pressure, thus supporting the hypothesis that lipocalins may be involved in chemical communication in arthropods.

POSITIVE FEEDBACK-ASSISTED SHORT/LONG-RANGE CELL SIGNALINGS IN MAPK CASCADES

2009 ◽  
Vol 20 (11) ◽  
pp. 1769-1787
Author(s):  
YANBIN ZHANG ◽  
KENIAN CHEN ◽  
JUNWEI WANG ◽  
AIMIN CHEN ◽  
TIANSHOU ZHOU
Keyword(s):  
Long Range ◽  
Positive Feedback ◽  
Information Transfer ◽  
Spatial Information ◽  
Signal Propagation ◽  
Large Cell ◽  
Long Distance ◽  
Mapk Cascades ◽  
Range Cell ◽  
Living Organisms

In this paper, we study potentials of positive feedback in spatial phosphoprotein signal propagation. For this, we consider a signaling pathway of four-tiered protein kinase cascades with each tier involving single (de)phosphorylation reactions only. In the case of a small cell, we propose a short positive feedback for short-range cell signaling, which can generate bistability to facilitate the phosphoprotein signal propagation from the plasma membrane to the periphery of cell nucleus. In contrast, in the case of a large cell for which the long-range signaling cannot be achieved by the short feedback, we propose a long positive feedback, and find that it can facilitate the propagation of phosphoprotein signal over a long distance. These results imply that positive-feedback mechanisms would be employed by living organisms for spatial information transfer and cellular decision-making processing.

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