Spinal neurite reabsorption and regrowth in vitro depend on the polarity of an applied electric field

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 31-41
Author(s):  
C.D. McCaig
Keyword(s):  
Electric Field ◽  
Neural Tube ◽  
Applied Field ◽  
Growth Cones ◽  
Individual Growth ◽  
Electrical Field ◽  
Field Reversal ◽  
Specific Change ◽  
Applied Electrical Field

Retraction and regrowth of frog neural tube neurites have been studied in vitro in control cultures and in the presence of a small, continuously applied electrical field. In control cultures, some degree of retraction was seen in 39% of neurites while 7% were reabsorbed completely. Reabsorption of anodal-facing neurites was at least twice as common, with 67% showing some retraction and 17% almost totally reabsorbed. Cathodal-facing neurites were spared from retraction. Following extreme reabsorption of anodal-facing neurites, reversal of the electric field promoted regeneration in 47% (9/19) of cases studied. growth cone morphology also was determined by the polarity of the applied field. Anodal-facing growth cones had fewer filopodia than cathodal-facing growth cones sharing the same cell body. Field reversal induced a polarity-specific change in filopodia number on individual growth cones: a shift from anodal to cathodal increased filopodia numbers and vice versa. Some possible mechanisms involved and the significance of these results are discussed.

Xenopus temporal retinal neurites collapse on contact with glial cells from caudal tectum in vitro

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 409-417
Author(s):  
A.R. Johnston ◽  
D.J. Gooday
Keyword(s):  
Cell Surface ◽  
Glial Cells ◽  
Optic Tectum ◽  
Surface Characteristics ◽  
Time Lapse ◽  
Growth Cones ◽  
Individual Growth

Nasal and temporal retinal neurites were confronted in culture with glial cells from the rostral and caudal parts of the optic tectum and with glial cells from the diencephalon. Twenty of each of the six classes of encounter between individual growth cones and isolated glial cells were analysed by time-lapse videorecording. The results show that growth cones from the temporal retina collapse when they contact glial cells from the caudal tectum, but do not collapse when they contact glia from other areas. Growth cones of nasal retinal fibres do not collapse on contact with any of the glial types examined. This suggests that the inhibitory phenomena described by others are in part due to the cell surface characteristics of glial cells, and that there are differences between glia from the front and back of the optic tectum.

scholarly journals The effect of an AC electric field on the dielectric properties of Pb(Mg1/3Nb2/3)O3 ceramic

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
E.C. Lima ◽  
J.D.S. Guerra ◽  
E.B. Araujo
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Statistical Model ◽  
Dielectric Response ◽  
Freezing Temperature ◽  
Dielectric Dispersion ◽  
Electrical Field ◽  
Ac Electric Field ◽  
Applied Electrical Field

The dynamic dielectric response of Pb(Mg1/3Nb2/3 )O3 ceramic was experimentally studied as a function of the EAC amplitude field. An increase in real dielectric permittivity was obtained by increasing the applied electrical field within the investigated temperature range for frequencies below 10 kHz. The temperature of maximum dielectric permittivity and freezing temperature decreased with an increase in E AC. Nonlinear permittivity was studied and found to behave similarly to freezing temperature. A statistical model was used to fit the dielectric dispersion of real dielectric permittivity with temperature and frequency. The results are discussed in terms of different factors’ contributions to dielectric permittivity under different EAC field conditions.

scholarly journals Cortical Network Synchrony Under Applied Electrical Field in vitro

2018 ◽  
Vol 12 ◽  
Author(s):  
Min D. Tang-Schomer ◽  
Taylor Jackvony ◽  
Sabato Santaniello
Keyword(s):  
Cortical Network ◽  
Electrical Field ◽  
Network Synchrony ◽  
Applied Electrical Field

Analysis of the Bias Dependent Spectral Response of a-SiC:H p-i-n Photodiode

2002 ◽  
Vol 715 ◽  
Author(s):  
P. Louro ◽  
A. Fantoni ◽  
Yu. Vygranenko ◽  
M. Fernandes ◽  
M. Vieira
Keyword(s):  
Bias Voltage ◽  
Voltage Dependence ◽  
Spectral Response ◽  
Surface Recombination ◽  
Electrical Field ◽  
Field Reversal ◽  
Current Voltage ◽  
Voltage Dependent ◽  
And Inversion ◽  
Device Operation

AbstractThe bias voltage dependent spectral response (with and without steady state bias light) and the current voltage dependence has been simulated and compared to experimentally obtained values. Results show that in the heterostructures the bias voltage influences differently the field and the diffusion part of the photocurrent. The interchange between primary and secondary photocurrent (i. e. between generator and load device operation) is explained by the interaction of the field and the diffusion components of the photocurrent. A field reversal that depends on the light bias conditions (wavelength and intensity) explains the photocurrent reversal. The field reversal leads to the collapse of the diode regime (primary photocurrent) launches surface recombination at the p-i and i-n interfaces which is responsible for a double-injection regime (secondary photocurrent). Considerations about conduction band offsets, electrical field profiles and inversion layers will be taken into account to explain the optical and voltage bias dependence of the spectral response.

Induction of melanocyte precursors from neural crest cells surrounding the neural tube-like structures developed in vitro using mouse ES cell culture

2007 ◽  
Vol 27 (1) ◽  
pp. 45-52
Author(s):  
Koh-ichi Atoh ◽  
Manae S. Kurokawa ◽  
Hideshi Yoshikawa ◽  
Chieko Masuda ◽  
Erika Takada ◽  
...  
Keyword(s):  
Cell Culture ◽  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Es Cell ◽  
Mouse Es Cell

scholarly journals Preparation of Fe3O4-Ag Nanocomposites with Silver Petals for SERS Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1288
Author(s):  
Thi Thuy Nguyen ◽  
Fayna Mammeri ◽  
Souad Ammar ◽  
Thi Bich Ngoc Nguyen ◽  
Trong Nghia Nguyen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hot Spots ◽  
Surface Enhanced Raman Spectroscopy ◽  
Electrical Field ◽  
Stabilizing Agents ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Sensing ◽  
Applied Electrical Field ◽  
Positively Charged

The formation of silver nanopetal-Fe3O4 poly-nanocrystals assemblies and the use of the resulting hetero-nanostructures as active substrates for Surface Enhanced Raman Spectroscopy (SERS) application are here reported. In practice, about 180 nm sized polyol-made Fe3O4 spheres, constituted by 10 nm sized crystals, were functionalized by (3-aminopropyl)triethoxysilane (APTES) to become positively charged, which can then electrostatically interact with negatively charged silver seeds. Silver petals were formed by seed-mediated growth in presence of Ag+ cations and self-assembly, using L-ascorbic acid (L-AA) and polyvinyl pyrrolidone (PVP) as mid-reducing and stabilizing agents, respectively. The resulting plasmonic structure provides a rough surface with plenty of hot spots able to locally enhance significantly any applied electrical field. Additionally, they exhibited a high enough saturation magnetization with Ms = 9.7 emu g−1 to be reversibly collected by an external magnetic field, which shortened the detection time. The plasmonic property makes the engineered Fe3O4-Ag architectures particularly valuable for magnetically assisted ultra-sensitive SERS sensing. This was unambiguously established through the successful detection, in water, of traces, (down to 10−10 M) of Rhodamine 6G (R6G), at room temperature.

scholarly journals Electrical Field-Assisted Gene Delivery from Polyelectrolyte Multilayers

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 133
Author(s):  
Yu-Che Cheng ◽  
Shu-Lin Guo ◽  
Kun-Da Chung ◽  
Wei-Wen Hu
Keyword(s):  
Gene Delivery ◽  
Electric Field ◽  
Treatment Time ◽  
Transfection Efficiency ◽  
Polyelectrolyte Multilayers ◽  
Aqueous Environment ◽  
Layer By Layer ◽  
Electrical Field ◽  
Lbl Assembly ◽  
Electric Field Treatment

To sustain gene delivery and elongate transgene expression, plasmid DNA and cationic nonviral vectors can be deposited through layer-by-layer (LbL) assembly to form polyelectrolyte multilayers (PEMs). Although these macromolecules can be released for transfection purposes, their entanglement only allows partial delivery. Therefore, how to efficiently deliver immobilized genes from PEMs remains a challenge. In this study, we attempt to facilitate their delivery through the pretreatment of the external electrical field. Multilayers of polyethylenimine (PEI) and DNA were deposited onto conductive polypyrrole (PPy), which were placed in an aqueous environment to examine their release after electric field pretreatment. Only the electric field perpendicular to the substrate with constant voltage efficiently promoted the release of PEI and DNA from PEMs, and the higher potential resulted in the more releases which were enhanced with treatment time. The roughness of PEMs also increased after electric field treatment because the electrical field not only caused electrophoresis of polyelectrolytes and but also allowed electrochemical reaction on the PPy electrode. Finally, the released DNA and PEI were used for transfection. Polyplexes were successfully formed after electric field treatment, and the transfection efficiency was also improved, suggesting that this electric field pretreatment effectively assists gene delivery from PEMs and should be beneficial to regenerative medicine application.

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