scholarly journals The ATP-Dependent Remodeler RSC Transfers Histone Dimers and Octamers through the Rapid Formation of an Unstable Encounter Intermediate

Biochemistry ◽  
2010 ◽  
Vol 49 (45) ◽  
pp. 9882-9890 ◽  
Author(s):  
Claire E. Rowe ◽  
Geeta J. Narlikar
Keyword(s):  
Histone Dimers ◽  
Rapid Formation

scholarly journals Ripple Formation during Oblique Angle Etching

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 272
Author(s):  
Mehmet F. Cansizoglu ◽  
Mesut Yurukcu ◽  
Tansel Karabacak
Keyword(s):  
Plasma Etching ◽  
Incidence Angle ◽  
Incident Beam ◽  
Root Mean Square Roughness ◽  
Sticking Coefficient ◽  
Oblique Angle ◽  
Nano Fabrication ◽  
Ripple Formation ◽  
Rapid Formation ◽  
Roughness Analysis

Chemical removal of materials from the surface is a fundamental step in micro- and nano-fabrication processes. In conventional plasma etching, etchant molecules are non-directional and perform a uniform etching over the surface. However, using a highly directional obliquely incident beam of etching agent, it can be possible to engineer surfaces in the micro- or nano- scales. Surfaces can be patterned with periodic morphologies like ripples and mounds by controlling parameters including the incidence angle with the surface and sticking coefficient of etching particles. In this study, the dynamic evolution of a rippled morphology has been investigated during oblique angle etching (OAE) using Monte Carlo simulations. Fourier space and roughness analysis were performed on the resulting simulated surfaces. The ripple formation was observed to originate from re-emission and shadowing effects during OAE. Our results show that the ripple wavelength and root-mean-square roughness evolved at a more stable rate with accompanying quasi-periodic ripple formation at higher etching angles (θ > 60°) and at sticking coefficient values (Sc) 0.5 ≤ Sc ≤ 1. On the other hand, smaller etching angle (θ < 60°) and lower sticking coefficient values lead to a rapid formation of wider and deeper ripples. This result of this study can be helpful to develop new surface patterning techniques by etching.

scholarly journals Rapid Formation of Stem Cell Spheroids Using Two-Dimensional MXene Particles

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 957
Author(s):  
JunHwee Jang ◽  
Eun-Jung Lee
Keyword(s):  
Stem Cell ◽  
Mass Production ◽  
Processing Time ◽  
Activity Levels ◽  
Two Dimensional ◽  
Spheroid Formation ◽  
Cell Spheroids ◽  
Tissue Healing ◽  
Rapid Formation ◽  
Cell Sources

Cell spheroids have been studied as a biomimic medicine for tissue healing using cell sources. Rapid cell spheroid production increases cell survival and activity as well as the efficiency of mass production by reducing processing time. In this study, two-dimensional MXene (Ti3C2) particles were used to form mesenchymal stem cell spheroids, and the optimal MXene concentration, spheroid-production times, and bioactivity levels of spheroid cells during this process were assessed. A MXene concentration range of 1 to 10 μg/mL induced spheroid formation within 6 h. The MXene-induced spheroids exhibited osteogenic-differentiation behavior, with the highest activity levels at a concentration of 5 μg/mL. We report a novel and effective method for the rapid formation of stem cell spheroids using MXene.

Membrane Alterations Induced by Amphiphiles

1989 ◽  
Vol 16 (3) ◽  
pp. 274-280
Author(s):  
Boris Isomaa ◽  
Henry Hägerstrand ◽  
Gun I.L. Paatero
Keyword(s):  
Ion Transport ◽  
Lipid Bilayer ◽  
Erythrocyte Membrane ◽  
Cell Shape ◽  
Osmotic Fragility ◽  
Molecular Shape ◽  
Specific Interactions ◽  
Amphiphilic Compounds ◽  
Rapid Formation ◽  
Polar Parts

Amphiphilic compounds with distinct apolar and polar parts are readily intercalated into the erythrocyte membrane. When intercalated into the membrane, amphiphiles are probably orientated so that the polar head is at the polar-apolar interface of the lipid bilayer and the hydrophobic part within the apolar core of the bilayer. However, by virtue of their difference in molecular shape from the bulk lipids of the lipid bilayer, it is possible that the intercalated amphiphiles are partly segregated from bulk lipids and accumulate at protein-lipid interfaces in the bilayer, where the packing of the bilayer lipids may be less ordered. Our studies show that amphiphiles, when intercalated into the erythrocyte membrane, trigger alterations in several membrane-connected functions. Some of the alterations induced (decreased osmotic fragility, increased passive potassium fluxes) seem to be due to non-specific interactions of the amphiphiles with the membrane, whereas other functions (ion transport mediated by membrane proteins, regulation of cell shape) seem to be sensitive to particular features of the amphiphiles. Our studies indicate that the intercalation of amphiphiles into the erythrocyte membrane must involve rearrangements within the lipid bilayer. We have suggested that, when intercalated into the lipid bilayer, amphiphiles trigger a rapid formation of non-bilayer phases, which protect the bilayer against a collapse and bring about a trans-bilayer redistribution of intercalated amphiphiles as well as of bilayer lipids. At high sublytic concentrations, this process may also involve a release of microvesicles from the membrane.

Arylation with Aryllead Triacetates Produced in situ by Mercury-Lead Exchange

1985 ◽  
Vol 38 (8) ◽  
pp. 1155 ◽  
Author(s):  
RP Kozyrod ◽  
JT Pinhey
Keyword(s):  
Good Yield ◽  
Lead Tetraacetate ◽  
Keto Ester ◽  
Rapid Formation

The addition of lead tetraacetate to diphenylmercury in chloroform leads to the rapid formation of a solution of phenyllead triacetate, which has been used directly for the C-phenylation of ethyl 2-oxocyclopentanecarboxylate (1) and 2-nitropropane in good yield. This method of arylation has been examined for a range of diorganolead compounds and the β-keto ester (1), and the results indicate that the method should be widely applicable.

scholarly journals Plasmid Transfer between the Bacillus thuringiensis Subspecies kurstaki andtenebrionis in Laboratory Culture and Soil and in Lepidopteran and Coleopteran Larvae

2000 ◽  
Vol 66 (1) ◽  
pp. 118-124 ◽  
Author(s):  
D. John I. Thomas ◽  
J. Alun W. Morgan ◽  
John M. Whipps ◽  
Jon R. Saunders
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacterial Population ◽  
Laboratory Culture ◽  
Plasmid Transfer ◽  
Donor Strain ◽  
Lepidopteran Insect ◽  
Lepidopteran Insects ◽  
Rapid Formation ◽  
Coleopteran Insect

ABSTRACT Plasmid transfer between Bacillus thuringiensis subsp.kurstaki HD1 and B. thuringiensis subsp.tenebrionis donor strains and a streptomycin-resistantB. thuringiensis subsp. kurstaki recipient was studied under environmentally relevant laboratory conditions in vitro, in soil, and in insects. Plasmid transfer was detected in vitro at temperatures of 5 to 37°C, at pH 5.9 to 9.0, and at water activities of 0.965 to 0.995, and the highest transfer ratios (up to 10−1 transconjugant/donor) were detected within 4 h. In contrast, no plasmid transfer was detected in nonsterile soil, and rapid formation of spores by the introduced strains probably contributed most to the lack of plasmid transfer observed. When aB. thuringiensis subsp. kurstaki strain was used as the donor strain, plasmid transfer was detected in killed susceptible lepidopteran insect (Lacanobia oleracea) larvae but not in the nonsusceptible coleopteran insect Phaedon chocleriae. When a B. thuringiensis subsp.tenerbrionis strain was used as the donor strain, no plasmid transfer was detected in either of these insects even when they were killed. These results show that in larger susceptible lepidopteran insects there is a greater opportunity for growth of B. thuringiensis strains, and this finding, combined with decreased competition due to a low initial background bacterial population, can provide suitable conditions for efficient plasmid transfer in the environment.

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