Effects of Molecular Length on Nematic Mixtures — IV: Structure Effects on Viscosity of Ester Mixtures

1984 ◽  
pp. 111-136 ◽  
Author(s):  
J. David Margerum ◽  
Siu-May Wong ◽  
John E. Jensen ◽  
Camille van Ast
Keyword(s):  
Molecular Length

Chromic Acid Etching of Polyethylene

1973 ◽  
Vol 31 ◽  
pp. 72-73
Author(s):  
J. D. Muzzy ◽  
R. D. Hester ◽  
J. L. Hubbard
Keyword(s):  
Chromic Acid ◽  
Low Cost ◽  
Acid Etching ◽  
Crystalline Morphology ◽  
Bulk Specimen ◽  
Morphological Studies ◽  
Perfect Form ◽  
Molecular Length ◽  
Lamellar Texture ◽  
Cost Studies

Polyethylene is one of the most important plastics produced today because of its good physical properties, ease of fabrication and low cost. Studies to improve the properties of polyethylene are leading to an understanding of its crystalline morphology. Polyethylene crystallized by evaporation from dilute solutions consists of thin crystals called lamellae. The polyethylene molecules are parallel to the thickness of the lamellae and are folded since the thickness of the lamellae is much less than the molecular length. This lamellar texture persists in less perfect form in polyethylene crystallized from the melt.Morphological studies of melt crystallized polyethylene have been limited due to the difficulty of isolating the microstructure from the bulk specimen without destroying or deforming it.

Paramyosin: Molecular Length and Assembly

Science ◽  
1969 ◽  
Vol 163 (3872) ◽  
pp. 1196-1198 ◽  
Author(s):  
J. Kendrick-Jones ◽  
C. Cohen ◽  
A. G. Szent-Gyorgyi ◽  
W. Longley
Keyword(s):  
Molecular Length

scholarly journals X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

2012 ◽  
Vol 3 ◽  
pp. 12-24 ◽  
Author(s):  
Hicham Hamoudi ◽  
Ping Kao ◽  
Alexei Nefedov ◽  
David L Allara ◽  
Michael Zharnikov
Keyword(s):  
Chain Length ◽  
Photoelectron Spectroscopy ◽  
Self Assembled Monolayers ◽  
Phenylene Ethynylene ◽  
X Ray ◽  
Molecular Length ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Gold Thiolate

Self-assembled monolayers (SAMs) of nitrile-substituted oligo(phenylene ethynylene) thiols (NC-OPEn) with a variable chain length n (n ranging from one to three structural units) on Au(111) were studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and near-edge absorption fine-structure spectroscopy. The experimental data suggest that the NC-OPEn molecules form well-defined SAMs on Au(111), with all the molecules bound to the substrate through the gold–thiolate anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36° for all the target systems. In contrast, the average twist of the OPEn backbone (planar conformation) was found to depend on the molecular length, being close to 45° for the films comprising the short OPE chains and ~53.5° for the long chains. Analysis of the data suggests that the attachment of the nitrile moiety, which served as a spectroscopic marker group, to the OPEn backbone did not significantly affect the molecular orientation in the SAMs.

scholarly journals Genotypic detection of some virulence factors among Aeromonas hydrophila Isolated from Diarrhea Cases (Iraq)

2018 ◽  
Vol 9 (SPL1) ◽  
Author(s):  
Ilham A Bunyan ◽  
Israa K Obais
Keyword(s):  
Virulence Factors ◽  
Aeromonas Hydrophila ◽  
Molecular Detection ◽  
Virulence Gene ◽  
Molecular Study ◽  
Protease Gene ◽  
Allelic Ladder ◽  
Specific Pcr ◽  
Molecular Length ◽  
Positive Results

The present study included the detection ofsome virulence factorsof Aeromonas hydrophila under molecular level to clinical isolates were taken from patients suffering from diarrhea during the period from July (2017) to October (2017). Molecular detection of Hemolysin gene (ahh) was done for all isolates. The results showed that all isolates (100%) gave positive results for this virulence gene. the positive results were detected by the presence of (130) bp bands when compared with allelic ladder. The genomic DNA of the samples was extracted and bands were observed by performing agarose gel electrophoresis. When PCR was performed,results clearly indicate that all isolated organisms contained serine protease gene and all the amplified products produced a band at the level of (900 bp) when compared with the allelic ladder. Molecular detection of this gene was carried out by using a specific PCR primer were done by comparison with allelic ladder which gave a (309bp) It was found that (Aerolysin) gene present in (12) (75%) of the positive samples. Lip gene was also detected in A. hydrophila samples and found that all 16 samples (100%) gave positive results to this gene which gave molecular length (382) bp. Molecular study was carried out to show the sequence identity of cytotonic enterotoxins gene in Aeromonas spp. to that in A. hydrophila. Analysis of the A. hydrophila genome revealed a number of a putative virulence factors,including a gene that heat-labile cytotonic enterotoxin (alt). Our study showed that all (16) isolates (100%) gave positive results to this gene,which gave molecular length (442)bp. Molecular detection of cytotonic enterotoxins gene (ast) was done for (16) A. hydrophila isolates and the results showed that all isolates have this gene (100%). The positive results for (ast) virulence were detected by the presence of (331) bp band compared with allelic ladder.

A Porous Media Model for Thin Film Lubrication

1995 ◽  
Vol 117 (1) ◽  
pp. 16-21 ◽  
Author(s):  
J. A. Tichy
Keyword(s):  
Reynolds Equation ◽  
Squeezing Flow ◽  
Thin Film Lubrication ◽  
Porous Layers ◽  
Porosity Parameter ◽  
Porous Media Model ◽  
Molecular Length ◽  
Load Increase ◽  
Thickness Parameter ◽  
Film Lubrication

A rheological model has been developed which can be applied to boundary lubrication. The model is applicable to thin films in which the molecular length scale is the same order as the film thickness. The micro structure is simulated by porous layers attached to the contact surfaces. The model contains three material properties: (1) viscosity, (2) the thickness of the porous layer, and (3) a porosity parameter. A modified Reynolds equation is developed. Behavior in two types of contacts is calculated: squeezing flow between crossed cylinders (Chan and Horn’s, 1985 drainage experiment) and a one-dimensional converging wedge contact. The effect of the layer thickness parameter is to increase the load and reduce the friction coefficient. Increasing the porosity parameter value tends to reduce the magnitude of the load increase.

Impact of Cationic Molecular Length of Ionic Liquid Electrolytes on Cell Performances of 18650 Supercapacitors

2021 ◽  
Author(s):  
Phatsawit Wuamprakhon ◽  
Ruttiyakorn Donthongkwa ◽  
Kanit Hantanasirisakul ◽  
Vinich Promarak ◽  
Jumras Limtrakul ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Porous Carbon ◽  
Room Temperature ◽  
Series Resistance ◽  
Room Temperature Ionic Liquids ◽  
Specific Cell ◽  
Equivalent Series Resistance ◽  
Molecular Length ◽  
Cell Capacitance

The specific cell capacitance, equivalent series resistance (ESR) and equivalent distributed resistance (EDR) of porous carbon-based supercapacitors linearly depend on the cation molecular length (1 dimension) of room-temperature ionic liquids.

How do smectic liquid crystals of different molecular length mix in thin films?

2002 ◽  
Vol 9 (S1) ◽  
pp. 443-446 ◽  
Author(s):  
H.R. Keymeulen ◽  
W.H. de Jeu ◽  
J.T. Slattery ◽  
M. Veum
Keyword(s):  
Thin Films ◽  
Liquid Crystals ◽  
Smectic Liquid Crystals ◽  
Molecular Length

scholarly journals Bundling of actin filaments by alpha-actinin depends on its molecular length.

1990 ◽  
Vol 110 (6) ◽  
pp. 2013-2024 ◽  
Author(s):  
R K Meyer ◽  
U Aebi
Keyword(s):  
Smooth Muscle ◽  
Actin Filament ◽  
Actin Filaments ◽  
Actin Binding ◽  
Molar Ratio ◽  
Cross Linking ◽  
Actin Bundle ◽  
Actin Bundles ◽  
Chicken Gizzard ◽  
Molecular Length

Cross-linking of actin filaments (F-actin) into bundles and networks was investigated with three different isoforms of the dumbbell-shaped alpha-actinin homodimer under identical reaction conditions. These were isolated from chicken gizzard smooth muscle, Acanthamoeba, and Dictyostelium, respectively. Examination in the electron microscope revealed that each isoform was able to cross-link F-actin into networks. In addition, F-actin bundles were obtained with chicken gizzard and Acanthamoeba alpha-actinin, but not Dictyostelium alpha-actinin under conditions where actin by itself polymerized into disperse filaments. This F-actin bundle formation critically depended on the proper molar ratio of alpha-actinin to actin, and hence F-actin bundles immediately disappeared when free alpha-actinin was withdrawn from the surrounding medium. The apparent dissociation constants (Kds) at half-saturation of the actin binding sites were 0.4 microM at 22 degrees C and 1.2 microM at 37 degrees C for chicken gizzard, and 2.7 microM at 22 degrees C for both Acanthamoeba and Dictyostelium alpha-actinin. Chicken gizzard and Dictyostelium alpha-actinin predominantly cross-linked actin filaments in an antiparallel fashion, whereas Acanthamoeba alpha-actinin cross-linked actin filaments preferentially in a parallel fashion. The average molecular length of free alpha-actinin was 37 nm for glycerol-sprayed/rotary metal-shadowed and 35 nm for negatively stained chicken gizzard; 46 and 44 nm, respectively, for Acanthamoeba; and 34 and 31 nm, respectively, for Dictyostelium alpha-actinin. In negatively stained preparations we also evaluated the average molecular length of alpha-actinin when bound to actin filaments: 36 nm for chicken gizzard and 35 nm for Acanthamoeba alpha-actinin, a molecular length roughly coinciding with the crossover repeat of the two-stranded F-actin helix (i.e., 36 nm), but only 28 nm for Dictyostelium alpha-actinin. Furthermore, the minimal spacing between cross-linking alpha-actinin molecules along actin filaments was close to 36 nm for both smooth muscle and Acanthamoeba alpha-actinin, but only 31 nm for Dictyostelium alpha-actinin. This observation suggests that the molecular length of the alpha-actinin homodimer may determine its spacing along the actin filament, and hence F-actin bundle formation may require "tight" (i.e., one molecule after the other) and "untwisted" (i.e., the long axis of the molecule being parallel to the actin filament axis) packing of alpha-actinin molecules along the actin filaments.

Sign in / Sign up

Export Citation Format

Share Document