Electrical Charge Density of Spleen Cells sensitized against L-strain Fibroblasts

Nature ◽  
1963 ◽  
Vol 200 (4907) ◽  
pp. 691-692 ◽  
Author(s):  
P. S. VASSAR ◽  
H. E. TAYLOR ◽  
C. F. A. CULLING
Keyword(s):  
Charge Density ◽  
Electrical Charge ◽  
Spleen Cells ◽  
Electrical Charge Density

scholarly journals Live Measurement of Electrical Charge Density in Materials using Off-Axis Electron Holography

2019 ◽  
Vol 25 (S2) ◽  
pp. 44-45
Author(s):  
E. Voelkl ◽  
F. Zheng ◽  
V. Migunov ◽  
M. Beleggia ◽  
R.E. Dunin-Borkowski
Keyword(s):  
Charge Density ◽  
Electrical Charge ◽  
Electron Holography ◽  
Electrical Charge Density

Quantification of the electrostatic properties of the glomerular filtration barrier modeled as a charged fiber matrix separating anionic from neutral Ficoll

2013 ◽  
Vol 304 (6) ◽  
pp. F781-F787 ◽  
Author(s):  
Carl M. Öberg ◽  
Bengt Rippe
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Glomerular Filtration ◽  
Surface Charge Density ◽  
Electrostatic Interactions ◽  
The Body ◽  
Electrical Charge ◽  
Glomerular Filtration Barrier ◽  
Filtration Barrier ◽  
Fiber Matrix

In the current study we explore the electrostatic interactions on the transport of anionic Ficoll (aFicoll) vs. neutral Ficoll (nFicoll) over the glomerular filtration barrier (GFB) modeled as a charged fiber matrix. We first analyze experimental sieving data for the rat glomerulus, and second, we explore some of the basic implications of a theoretical model for the electrostatic interactions between a charged solute and a charged fiber-matrix barrier. To explain the measured difference in glomerular transport between nFicoll and aFicoll (Axelsson J, Sverrisson K, Rippe A, Fissell W, Rippe B. Am J Physiol 301: F708–F712, 2011), the present simulations demonstrate that the surface charge density needed on a charged fiber matrix must lie between −0.005 C/m2 and −0.019 C/m2, depending on the surface charge density of the solute. This is in good agreement with known surface charge densities for many proteins in the body. In conclusion, the current results suggest that electrical charge makes a moderate contribution to glomerular permeability, while molecular size and conformation seem to be more important. Yet, the weak electrical charge obtained in this study can be predicted to nearly totally exclude albumin from permeating through “high-selectivity” pathways in a charged-fiber matrix of the GFB.

scholarly journals THE ROLE OF THYMOCYTES AND BONE MARROW CELLS IN DEFINING THE RESPONSE TO THE DINITROPHENYL HAPTEN ATTACHED TO POSITIVELY AND NEGATIVELY CHARGED SYNTHETIC POLYPEPTIDE CARRIERS

1973 ◽  
Vol 137 (1) ◽  
pp. 183-195 ◽  
Author(s):  
Yuval Karniely ◽  
Edna Mozes ◽  
G. M. Shearer ◽  
Michael Sela
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Electrical Charge ◽  
Spleen Cells ◽  
Net Charge ◽  
Cellular Basis ◽  
Charged Carrier ◽  
Synthetic Polypeptide ◽  
Positively Charged ◽  
Marrow Cells

An inverse relationship exists between the net electrical charge of immunogens and the antibodies they elicit (1). Results of an earlier study have demonstrated that the net charge phenomenon has a cellular basis, since the immune response potential of murine spleen cells to 2,4-dinitrophenyl (DNP) on a negatively charged synthetic polypeptide carrier was reduced by cell fractionation over negatively charged glass beads, whereas the response to the same hapten on a positively charged carrier was unaffected (14). To verify that the net charge correlation is expressed at the cellular level, spleen cells were fractionated over positively charged poly-L-lysine-coated glass bead columns, and their immunocompetence to DNP on positively and negatively charged carriers was tested by cell transfers in irradiated recipient mice. In this case, the fractionated cells showed reduced response potential to DNP on the positively charged carrier only. Thus, the cellular basis of the net charge phenomenon has been demonstrated for both positively and negatively charged immunogens (for the same specificity) by cell separation techniques over columns of opposite charge. In order to establish whether the cell population relevant for the charge properties of immunogens was of thymus or marrow origin, thymocytes and bone marrow cells were selectively passed over positively or negatively charged columns and mixed with unfractionated cells of the complementary type. Transfers of the filtered and unfiltered cell mixtures in irradiated recipient mice immunized with DNP on either a positive or a negative synthetic polypeptide carrier indicated that fractionation of thymocytes, but not of marrow cells, correlated with the spleen population. Thus, thymocytes fractionated over negatively charged columns and mixed with unfractionated marrow cells exhibited reduced response to DNP on the negative carrier, but normal responses to DNP on the positive carrier. The opposite result was obtained when thymocytes were passed over positively charged columns. No effect on the anti-DNP response was detected by filtration of bone marrow cells over columns of either charge. These findings indicate that it is possible to distinguish between thymocytes on the basis of their capacity to react with more acidic or more basic surfaces and that a population of thymus-derived cells may recognize immunogens on the basis of their overall electrical charge. No evidence was found by these techniques that marrow-derived cells contribute to the net charge phenomenon.

scholarly journals Charged Modification of Hydrogel for Nerve Regeneration

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Mahrokh Dadsetan ◽  
Andrew M. Knight ◽  
Catalina Vallejo ◽  
Lichun Lu ◽  
Anthony J. Windebank ◽  
...  
Keyword(s):  
Charge Density ◽  
Neurite Outgrowth ◽  
Nerve Regeneration ◽  
Cell Attachment ◽  
Hydrolytic Degradation ◽  
Oxidative Degradation ◽  
Electrical Charge ◽  
Swelling Ratio ◽  
Positively Charged

Natural and synthetic hydrogels have attracted much attention for nerve regeneration. Previous studies have shown that electrical charge has significant effect on stimulation of neurite outgrowth. In this work, incorporation of a positively charged monomer into the photocrosslinkable oligo(polyethylene glycol) fumarate (OPF) hydrogel has been investigated. We have evaluated the effect of localized positive charge on neurite outgrowth in culture with an objective that positively charged hydrogels ultimately can be used for stimulating in vivo nerve regeneration. The effect of charged modification has been also studied on mechanical properties and swelling ratio of these hydrogels. Our data indicated that with increasing charge density hydrogels swelling ratio increased in water, however it remained constant in PBS. We also demonstrated that compressive modulus and tensile strength of the hydrogels improved with incorporation of electrical charge into the hydrogels. Biodegradation of modified hydrogels was investigated in a series of biomimetic solutions. OPF hydrogels appeared to be more susceptible to oxidative degradation as opposed to the hydrolytic degradation in enzymes and acidic solution, and the degradation rate was correlated to the PEG molecular weight and charge density of the hydrogels. To investigate the effect of charge modification on nerve cell attachment and differentiation, dissociated dorsal root ganglion (DRG) cells were plated onto the modified and unmodified hydrogels surfaces. DRG cells attached and extended their neurites more readily on the surface of positively charged hydrogels as opposed to the unmodified hydrogels.

Incommensurate modulated phases of the NbxTa1-xTe4 charge density wave system

1992 ◽  
Vol 50 (1) ◽  
pp. 58-59
Author(s):  
S. Ritchie ◽  
J. C. Bennett ◽  
A. Prodan ◽  
F.W. Boswell ◽  
J.M. Corbett
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Direct Evidence ◽  
Density Wave ◽  
Wave System ◽  
Modulated Phases ◽  
Metal Atoms ◽  
Incommensurate Modulation ◽  
End Members ◽  
Modulation Wave Vector

A continuous sequence of compounds having composition NbxTa1-xTe4; 0 ≤ x ≤ 1 have been studied by electron diffraction and microscopy. Previous studies have shown that the end members of the series, TaTε4 and NbTε4 possess a quasi-one-dimensional character and exhibit charge density wave (CDW) distortions. In these compounds, the subcell structure is tetragonal with axes (a × a × c) and consists of the metal atoms (Nb or Ta) centered within an extended antiprismatic cage of Te atoms. At room temperature, TaTε4 has a commensurate modulation structure with a 2a × 2a × 3c unit cell. In NbTε4, an incommensurate modulation with × ∼ 16c axes is observed. Preliminary studies of the mixed compounds NbxTα1-xTε4 showed a discontinuous jump of the modulation wave vector commensurate to incommensurate when the Nb dopant concentration x, exceeded x ≃ 0.3, In this paper, the nature of the compositional dependence of is studied in greater detail and evidence is presented for a stepwise variation of . This constitutes the first direct evidence for a Devil's staircase in CDW materials.

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