The formation of free ions and electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane–chloroform mixtures at low concentrations of AOT

2020 ◽  
Vol 22 (26) ◽  
pp. 14671-14681 ◽  
Author(s):  
Alexander I. Bulavchenko ◽  
Nikita O. Shaparenko ◽  
Nikolay B. Kompan’kov ◽  
Pavel S. Popovetskiy ◽  
Marina G. Demidova ◽  
...  
Keyword(s):  
Electrophoretic Mobility ◽  
Au Nanoparticles ◽  
Free Ions ◽  
Low Concentrations

The electrophoretic mobility of Ag and Au nanoparticles in n-hexadecane–chloroform mixtures was studied as a function of the chloroform content (from 0 to 100 vol%).

Effects of cytochalasin B on the aggregation, electrophoretic mobility and surface morphology of chick neural retina cells

1975 ◽  
Vol 17 (3) ◽  
pp. 371-379
Author(s):  
G.E. Jones
Keyword(s):  
Surface Morphology ◽  
Electrophoretic Mobility ◽  
Cytochalasin B ◽  
Neural Retina ◽  
Initial Rise ◽  
Low Concentrations ◽  
Significant Difference ◽  
Site Of Action ◽  
High Concentrations ◽  
Free Media

Over a concentration range of o-5-10 mug/cm-3, cytochalasin B caused a biphasic change in the electrophoretic mobility of disaggregated neural retina cells. An initial rise in anodal mobility at low concentrations of the drug was transformed into a reduction in the mobility below that of the control at a concentration of 10 mug/cm-3. The effect of cytochalasin B was found to be reversible by washing treated cells in cytochalasin B-free media. This was investigated at a concentration of cytochalasin at which the greatest difference existed between the mobilities of the control and experimental cell suspensions. Reaggregation of cell dispersions failed to show any significant difference in the rate of aggregation between cytochalasin B-treated cells and the control. Scanning electron microscopy of cells fixed while in suspension also showed little significant change in the surface morphology upon application of cytochalasin B. In high concentrations of the drug cells appeared somewhat smoother in outline, but no correlation was found between changes in surface morphology and the variations in cell electrophoretic mobility. It is concluded that the observed changes in electrophoretic mobility may be attributed to a binding of cytochalasin B to the cell membrane. This lends support to the hypothesis that the primary site of action of cytochalasin B may be the plasma membrane.

Electrophoretic mobility of microsomes from rat liver

1977 ◽  
Vol 23 (1) ◽  
pp. 285-297
Author(s):  
D. Blad ◽  
L. Winqvist ◽  
G. Dallner
Keyword(s):  
Electrophoretic Mobility ◽  
Liver Microsomes ◽  
Protein Species ◽  
Electrophoretic Mobilities ◽  
Low Concentrations ◽  
Structural Differences ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
And Control ◽  
Phosphate Groups

The electrophoretic mobilities of rough and smooth microsomes were studied using free electrophoresis in a sucrose gradient. Rough microsomes have a higher net negative surface charge but removal of the ribosomes decreases their mobility to that of smooth microsomes. Treatment with neuraminidase and phospholipases C and D does not affect the mobility of total smooth microsomes, but this mobility is increased by approximately 20% after trypsin and papain treatment and by approximately 12% after phospholipase A treatment. Further treatment of trypsin-digested smooth microsomes with phospholipase C re-establishes the original mobility. This effect is not caused by the removal of lipid phosphate groups, but by the liberation of negatively charged protein species that are normally buried under trypsin-sensitive proteins. Low concentrations of trypsin also solubilize enzyme proteins from smooth liver microsomes of phenobarbital-treated rats, but the electrophoretic mobility is not increased, indicating structural differences between induced and control membranes.

scholarly journals Fabrication of SERS Substrates Using Au Nanoparticles Prepared by Laser Ablation in Distilled Water and Detection of Tetracycline at Low Concentrations

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Nguyen The Binh ◽  
Nguyen Quang Dong
Keyword(s):  
Laser Ablation ◽  
Malachite Green ◽  
Au Nanoparticles ◽  
High Sensitivity ◽  
Sers Substrate ◽  
Au Nps ◽  
Si Substrates ◽  
Sers Substrates ◽  
Low Concentrations ◽  
Average Size

We studied to produce SERS substrates using gold (Au) nanoparticles (AuNPs) prepared by pulse laser ablation (PLA) in water. The colloidal Au NPs with average size of 23nm were deposited on a silicon wafer to form AuNPs/Si SERS substrate. Malachite green was chosen as a test analyte to examine the sensitivity of the SERS substrates. The SERS enhancement factor of the AuNPs/Si was found to be about 106.  The high sensitivity of the AuNPs/Si substrates was confirmed by the SERS spectra of malachite green detected with high quality at concentrations of 0.1ppm. The SERS substrates can detect SERS spectra of tetracycline at low concentrations of around 1ppm.

scholarly journals EFFECT OF PROTEINS ON ELECTROPHORETIC MOBILITY AND SEDIMENTATION VELOCITY OF RED CELLS

1936 ◽  
Vol 19 (5) ◽  
pp. 715-726 ◽  
Author(s):  
B. R. Monaghan ◽  
H. L. White
Keyword(s):  
Electrophoretic Mobility ◽  
Bulk Viscosity ◽  
Sedimentation Velocity ◽  
Red Cells ◽  
Red Cell ◽  
Cell Surfaces ◽  
Concentrated Solutions ◽  
Low Concentrations ◽  
Different Types ◽  
The Difference

The isoelectric point of normal red cells cannot be measured but is certainly lower than that of any plasma protein. Red cells are easily damaged so that they will adsorb proteins from low concentrations. Normal red cells do not adsorb protein even from concentrated solutions, as is evidenced by the finding that the ratio of the mobility of the cells to that of the proteins themselves is at least as high in concentrated casein, albumin, gelatin, or fibrinogen solutions as in dilute. The finding that the observed mobility of red cells is unchanged or only slightly decreased when bulk viscosity is increased by added protein is interpreted as indicating that the red cell surfaces are hydrated. The aggregating effect of certain proteins has been determined and is assumed to be due to their dehydrating effect on the cells. Some types of cells, as beef, are not aggregated, presumably because they are resistant to this dehydrating effect. The difference in the behavior of different types of red cells demonstrates the importance of the nature of the cell as well as of the medium in determining the rate of aggregation and therefore of sedimentation.

scholarly journals Characterization of the serum lipoproteins and their apoproteins in hypercholesterolaemic guinea pigs

1977 ◽  
Vol 167 (1) ◽  
pp. 9-21 ◽  
Author(s):  
M J Chapman ◽  
G L Mills
Keyword(s):  
Electrophoretic Mobility ◽  
Guinea Pigs ◽  
Corn Oil ◽  
Average Particle Size ◽  
High Density Lipoproteins ◽  
Control Group ◽  
Chow Diet ◽  
Average Particle ◽  
Low Density ◽  
Low Concentrations

1. Hypercholesterolaemia was induced in male guinea pigs after 6 days on a chow diet supplemented with 1.6% (w/w) cholesterol and 15% (w/w) corn oil. Both the VLD (very-low-density) and LD (low-density) lipoproteins were increased in cholesterol-fed animals, although the low concentrations of HD (high-density) lipoproteins remained essentially unchanged. LD lipoproteins of d 1.019-1.100 were the major class, accounting for 74% of the total substances of d less than 1.100. 2. Both VLD and LD lipoproteins exhibited alterations in their chemical composition, physical properties and apolipoprotein content. The VLD lipoproteins in cholesterolaemic animals were rich in cholesterol (25.9%), deficient in protein (4.9%) and exhibited electrophoretic mobility greater than that of beta-globulin; their average particle size (64.5 nm) was larger than that in controls (46.3 nm). The LD lipoproteins in animals fed on the experimental diet were also richer in cholesterol (53.1%) and of larger diameter (24.3 nm) than in the control group (41.1% and 21.4 nm respectively). 3. The apolipoprotein-B content of both VLD and LD lipoproteins was elevated in cholesterolaemic animals, particularly in the VLD class, where it represented 74.8% of the total protein moiety. 4. Apo-VLD lipoprotein exhibited an increase from 6 to 19% in its complement of tetramethylurea-soluble apolipoproteins with low electrophoretic mobility (relative mobility less than 0.29); this was primarily accounted for by apolipoproteins characterized by high arginine (7.2 and 6.4% respectively) and glutamic acid (20.1 and 20.0% respectively) contents. 5. By contrast, there was little change in the soluble apolipoproteins of LD lipoproteins in hypercholesterolaemic animals.6. These studies show the response of the guinea pig to dietary fat and cholesterol to be distinct from that elicited by similar stimuli in the rabbit, rat, pig and dog.

scholarly journals Evaluation of the X-Ray Absorption by Gold Nanoparticles Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
R. Künzel ◽  
E. Okuno ◽  
R. S. Levenhagen ◽  
N. K. Umisedo
Keyword(s):  
Gold Nanoparticles ◽  
Ionization Chamber ◽  
Au Nanoparticles ◽  
Low Energy ◽  
Distilled Water ◽  
Gold Concentration ◽  
X Ray ◽  
Cdte Detector ◽  
Low Concentrations ◽  
X Ray Absorption

The increase in the X-ray absorption due to gold nanoparticles was investigated by using aqueous solutions containing gold (Au) nanoparticles. A sample with 15 nm in size nanoparticles and 0.5 mg/mL gold concentration and a distilled water sample were used. Transmitted X-ray beams through the samples were registered with a CdTe detector and with an ionization chamber. Results show an enhancement in the X-ray absorption in the range 20%–6% for beams generated from 20 kV to 120 kV tube voltages, respectively. Results show that the use of gold nanoparticles, even at low concentrations, should result in a significant contrast enhancement for low-energy X-ray beams.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

1995 ◽  
Vol 53 ◽  
pp. 584-585
Author(s):  
Uwe Lücken ◽  
Michael Felsmann ◽  
Wim M. Busing ◽  
Frank de Jong
Keyword(s):  
Life Science ◽  
Focal Length ◽  
Objective Lens ◽  
High Contrast ◽  
Contrast Imaging ◽  
X Ray ◽  
Forming Mechanism ◽  
Similar Image ◽  
High Contrast Imaging ◽  
Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

1987 ◽  
Vol 45 ◽  
pp. 924-925
Author(s):  
F. A. Durum ◽  
R. G. Goldman ◽  
T. J. Bolling ◽  
M. F. Miller
Keyword(s):  
Inclusion Bodies ◽  
Large Scale ◽  
Recombinant Dna ◽  
Test System ◽  
Cell Protein ◽  
Gram Negative Bacteria ◽  
Cytoplasmic Inclusions ◽  
Isolation And Purification ◽  
E Coli ◽  
Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

Phase behavior of cationic and anionic surfactants at low concentrations

1992 ◽  
Vol 50 (1) ◽  
pp. 694-695
Author(s):  
E. Naranjo
Keyword(s):  
Phase Behavior ◽  
Structural Characterization ◽  
Dynamic Systems ◽  
Anionic Surfactants ◽  
Intermolecular Forces ◽  
Stable Form ◽  
Surfactant Mixtures ◽  
Low Concentrations ◽  
Cationic And Anionic Surfactants ◽  
General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

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