Binding, unbinding and aggregation of crescent-shaped nanoparticles on nanoscale tubular membranes

Soft Matter ◽  
2021 ◽  
Author(s):  
Eric J. Spangler ◽  
Alexander D. Olinger ◽  
P. B. Sunil Kumar ◽  
Mohamed Laradji
Keyword(s):  
Phase Diagram ◽  
Adhesion Strength ◽  
Radius Of Curvature ◽  
Tubular Membrane ◽  
Shaped Nanoparticles ◽  
Tubular Membranes

Binding/unbinding phase diagram of a crescent-shaped nanoparticle on a tubular membrane as a function of the tubular membrane radius of curvature and adhesion strength.

scholarly journals The mechanism of osmotically induced sealing of cardiac t tubules

2020 ◽  
Vol 319 (2) ◽  
pp. H410-H421
Author(s):  
Keita Uchida ◽  
Azadeh Nikouee ◽  
Ian Moench ◽  
Greta Tamkus ◽  
Yasmine Elghoul ◽  
...  
Keyword(s):  
Tubular Membrane ◽  
Threshold Phenomenon ◽  
T Tubules ◽  
Tubular Membranes ◽  
Intracellular Pressure

This study provides new insights into how t-tubular membranes respond to osmotic forces. In particular, the data show that osmotically induced sealing of cardiac t tubules is a threshold phenomenon initiated by detachment of t-tubular membrane from the underlying cytoskeleton. The findings are consistent with the hypothesis that final sealing of t tubules is driven by negative hydrostatic intracellular pressure coincident with cell shrinking.

Oxygen Separator Based on SrCo0.8Fe0.1Sn0.1O3-δ Permeable Membranes

2007 ◽  
Vol 334-335 ◽  
pp. 921-924 ◽  
Author(s):  
Chuan Gang Fan ◽  
Yan Bo Zuo ◽  
Jun Qing Lu ◽  
Si Wei Zhu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Permeation Rate ◽  
Tubular Membrane ◽  
Tubular Membranes ◽  
Extrusion Method

In this article, the densely SrCo0.8Fe0.1Sn0.1O3-δ (SSCF) tubular membranes were prepared by the traditional extrusion method. The prototype oxygen separator was constructed by the resulting SSCF tubular membrane. The resulting oxygen product had purity over 99%. At 920oC, a tubular membrane with a wall thickness of 1.4mm, had the permeation rate of 2.4ml/min.cm2, which kept unchanged during 1000hrs operation.

Preparation of Polyethersulfone Ultrafiltration Tubular Membranes with Superior Properties

2011 ◽  
Vol 221 ◽  
pp. 216-220 ◽  
Author(s):  
Jun Liu ◽  
En Hua Liu
Keyword(s):  
Low Temperature ◽  
Phase Inversion ◽  
Membrane Preparation ◽  
Coagulation Bath ◽  
Test Results ◽  
Tubular Membrane ◽  
Membrane Performance ◽  
Peg 400 ◽  
Optimized Conditions ◽  
Tubular Membranes

A novel polyethersulfone (PES) tubular membrane preparation by phase inversion via immersion precipitation using N,N-dimethylacetamide (DMAc) as the solvent, PEG-400 as the additive. The effects of membrane preparation conditioans on membrane performance were investigated. It was found that the flux was increased by adding ethanol into the coagulation bath. And the low temperature of coagulation bath also improve membrane’s rejection. Test results show that the flux can be up to 160 L•m-2h-1 and the rejection can reach more than 97% (for ovalbvmin) under optimized conditions.

scholarly journals Actin modulates shape and mechanics of tubular membranes

2020 ◽  
Vol 6 (17) ◽  
pp. eaaz3050
Author(s):  
A. Allard ◽  
M. Bouzid ◽  
T. Betz ◽  
C. Simon ◽  
M. Abou-Ghali ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Mammalian Cells ◽  
Intracellular Transport ◽  
Plant Cells ◽  
Tube Surface ◽  
Apparent Contradiction ◽  
Single Tube ◽  
Tubular Membrane ◽  
Tubular Membranes

The actin cytoskeleton shapes cells and also organizes internal membranous compartments. In particular, it interacts with membranes for intracellular transport of material in mammalian cells, yeast, or plant cells. Tubular membrane intermediates, pulled along microtubule tracks, are formed during this process and destabilize into vesicles. While the role of actin in tubule destabilization through scission is suggested, literature also provides examples of actin-mediated stabilization of membranous structures. To directly address this apparent contradiction, we mimic the geometry of tubular intermediates with preformed membrane tubes. The growth of an actin sleeve at the tube surface is monitored spatiotemporally. Depending on network cohesiveness, actin is able to entirely stabilize or locally maintain membrane tubes under pulling. On a single tube, thicker portions correlate with the presence of actin. These structures relax over several minutes and may provide enough time and curvature geometries for other proteins to act on tube stability.

scholarly journals Actin modulates shape and mechanics of tubular membranes

2019 ◽  
Author(s):  
A. Allard ◽  
M. Bouzid ◽  
T. Betz ◽  
C. Simon ◽  
M. Abou-Ghali ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Mammalian Cells ◽  
Intracellular Transport ◽  
Plant Cells ◽  
Tube Surface ◽  
Apparent Contradiction ◽  
Single Tube ◽  
Tubular Membrane ◽  
Tubular Membranes

The actin cytoskeleton shapes cells and also organizes internal membranous compartments. In particular, it interacts with membranes in intracellular transport of material in mammalian cells, yeast or plant cells. Tubular membrane intermediates, pulled along microtubule tracks, are involved during these processes, and destabilize into vesicles. While the role of actin in this destabilization process is still debated, literature also provide examples of membranous structures stabilization by actin. To directly address this apparent contradiction, we mimic the geometry of tubular intermediates with preformed membrane tubes. The growth of an actin sleeve at the tube surface is monitored spatio-temporally. Depending on network cohesiveness, actin is able to stabilize, or maintain membrane tubes under pulling. Indeed, on a single tube, thicker portions correlate with the presence of actin. Such structures relax over several minutes, and may provide enough time and curvature geometries for other proteins to act on tube stability.

Field ion microscopy

1988 ◽  
Vol 46 ◽  
pp. 434-435
Author(s):  
Gert Ehrlich
Keyword(s):  
Low Temperature ◽  
Sample Surface ◽  
Low Pressure ◽  
Radius Of Curvature ◽  
Field Ion Microscopy ◽  
Phosphor Screen ◽  
Ion Microscopy ◽  
Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

The buckling of thin EM specimens

1990 ◽  
Vol 48 (4) ◽  
pp. 850-851
Author(s):  
A.R. Thölén
Keyword(s):  
Electron Microscope ◽  
Elastic Properties ◽  
Crystal Surface ◽  
Specimen Surface ◽  
Radius Of Curvature ◽  
Thin Foils ◽  
Thin Electron ◽  
Regular Patterns

Thin electron microscope specimens often contain irregular bend contours (Figs. 1-3). Very regular bend patterns have, however, been observed around holes in some ion-milled specimens. The purpose of this investigation is twofold. Firstly, to find the geometry of bent specimens and the elastic properties of extremely thin foils and secondly, to obtain more information about the background to the observed regular patterns.The specimen surface is described by z = f(x,y,p), where p is a parameter, eg. the radius of curvature of a sphere. The beam is entering along the z—direction, which coincides with the foil normal, FN, of the undisturbed crystal surface (z = 0). We have here used FN = [001]. Furthermore some low indexed reflections are chosen around the pole FN and in our fcc crystal the following g-vectors are selected:

Point-Cathode Electron Gun Using Electron-Beam Bombardment for Cathode Tip Heating

1990 ◽  
Vol 48 (1) ◽  
pp. 198-199
Author(s):  
Ryo Iiyoshi ◽  
Susumu Maruse ◽  
Hideo Takematsu
Keyword(s):  
Electron Beam ◽  
Tungsten Wire ◽  
Local Heating ◽  
Electron Gun ◽  
Original Position ◽  
Beam Power ◽  
Radius Of Curvature ◽  
High Brightness ◽  
Beam Focusing ◽  
Time Operation

Point cathode electron gun with high brightness and long cathode life has been developed. In this gun, a straightened tungsten wire is used as the point cathode, and the tip is locally heated to higher temperatures by electron beam bombardment. The high brightness operation and some findings on the local heating are presented.Gun construction is shown in Fig.l. Small heater assembly (annular electron gun: 5 keV, 1 mA) is set inside the Wehnelt electrode. The heater provides a disk-shaped bombarding electron beam focusing onto the cathode tip. The cathode is the tungsten wire of 0.1 mm in diameter. The tip temperature is raised to the melting point (3,650 K) at the beam power of 5 W, without any serious problem of secondary electrons for the gun operation. Figure 2 shows the cathode after a long time operation at high temperatures, or high brightnesses. Evaporation occurs at the tip, and the tip part retains a conical shape. The cathode can be used for a long period of time. The tip apex keeps the radius of curvature of 0.4 μm at 3,000 K and 0.3 μm at 3,200 K. The gun provides the stable beam up to the brightness of 6.4×106 A/cm2sr (3,150 K) at the accelerating voltage of 50 kV. At 3.4×l06 A/cm2sr (3,040 K), the tip recedes at a slow rate (26 μm/h), so that the effect can be offset by adjusting the Wehnelt bias voltage. The tip temperature is decreased as the tip moves out from the original position, but it can be kept at constant by increasing the bombarding beam power. This way of operation is possible for 10 h. A stepwise movement of the cathode is enough for the subsequent operation. Higher brightness operations with the rapid receding rates of the tip may be improved by a continuous movement of the wire cathode during the operations. Figure 3 shows the relation between the beam brightness, the tip receding rate by evaporation (αis the half-angle of the tip cone), and the cathode life per unit length, as a function of the cathode temperature. The working life of the point cathode is greatly improved by the local heating.

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