scholarly journals Some related aspects of platypus electroreception: temporal integration behaviour, electroreceptive thresholds and directionality of the bill acting as an antenna

1998 ◽  
Vol 353 (1372) ◽  
pp. 1211-1219 ◽  
Author(s):  
Tore T. Fjällbrant ◽  
Paul R. Manger ◽  
John D. Pettigrew
Keyword(s):  
Electric Field ◽  
Close Relationships ◽  
Temporal Integration ◽  
Radar Target ◽  
Electrical Field ◽  
Number Of Factors ◽  
Observed Behaviour ◽  
Prey Localization ◽  
Field Decay ◽  
Electrical Stimuli

This paper focuses on how the electric field from the prey of the platypus is detected with respect to the questions of threshold determination and how the platypus might localize its prey. A new behaviour in response to electrical stimuli below the thresholds previously reported is presented. The platypus shows a voluntary exploratory behaviour that results from a temporal integration of a number of consecutive stimulus pulses. A theoretical analysis is given, which includes the threshold dependence on the number of receptors and temporal integration of consecutive stimuli pulses, the close relationships between electrical field decay across the bill, electroreceptive thresholds and directionality of the platypus bill acting as an antenna. It is shown that a lobe shape, similar to that which has been measured, can be obtained by combining responses in a specific way from receptors sensing the electric field decay across the bill. Two possible methods for such combinations are discussed and analysed with respect to measurements and observed behaviour of the platypus. A number of factors are described which need to be considered when electroreceptive thresholds are to be determined. It is shown that some information about the distance to the source is theoretically available from the pattern of field decay across the platypus's bill. The paper includes a comparative analysis of radar target tracking and platypus prey localization.

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.

scholarly journals The Polymerization of MMA and ST to Prepare Material with Gradient Refractive Index in Electric Field

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Yao Huang ◽  
Daming Wu ◽  
Dongyun Ren ◽  
Qingyun Meng ◽  
Xiaojun Di
Keyword(s):  
Molecular Weight ◽  
Refractive Index ◽  
Electric Field ◽  
Cylindrical Sample ◽  
Electrical Field ◽  
Molecular Weights ◽  
The Matrix ◽  
Gradient Refractive Index ◽  
Scattering Material ◽  
Different Parts

Light scattering material with gradient refractive index was prepared under the electrical field by taking methyl methacrylate (MMA) monomer as the matrix with the addition of a little preheated styrene (ST) and peroxidation benzoin formyl (BPO). The material obtained under electrical field presented different transmittance and molecular weight at different parts of the cylindrical sample along the axis of the direction of electric field which led to the layering phenomenon and gradient refractive index. The disparity of molecular weight between different layers can be as much as 230 thousand. There were several peaks in the figure of GPC test of the sample under electric field. This proved that there were polymers with different molecular weights in the sample. Therefore, it can be concluded that electrical field has a significant effect on polymerization.

scholarly journals EFFECT OF ALUMINUM FOILS NUMBER AND ITS LENGTH IN IMPROVEMENT OF ELECTRIC FIELD DISTRIBUTION OF HIGH VOLTAGE CONDENSER BUSHING

2021 ◽  
Vol 25 (4) ◽  
pp. 67-83
Author(s):  
Zahraa G. Mustafa ◽  
◽  
Kassim R. Hameed ◽  
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
High Voltage ◽  
Ansys Software ◽  
Electrical Field ◽  
Stress Control ◽  
Electrical Stress ◽  
Maximum Value ◽  
Contour Plots ◽  
High Voltage System

High voltage condenser bushing is one of the important component that is widely used in the high voltage system. At high voltage levels more than 52kV the distribution of electric field in condenser bushing is irregular between the lead conductor and the grounded metallic flange. This paper studied the effects of changing in both: the number layers of aluminum foils and Oil impregnated Paper (OIP), increasing the length of aluminum foils layers, and also increasing the thickness of OIP layer on the distribution of electric potential and electric field in condenser bushing by using Finite Element Method (FEM) and built the bushing model in ANSYS software. The harmonic analysis was performed of the bushing model at maximum value of withstand voltage test at 50Hz, from the analysis results are obtained the maximum value of electric field on the inner and outer surface of the bushing, the obtained electric field values were good and acceptable compared to the permissible electrical stress values of the dielectric insulators. This work can also aid in the design of high voltage bushing stress control, a knowledge of the electrical field distribution in bushing geometry. Moreover the results of analysis are shown as contour plots, graphs plotted, and tables.

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.

Electric Field Induced Patterning of Polymer Films

2001 ◽  
Vol 705 ◽  
Author(s):  
David G. Bucknall ◽  
G. Andrew ◽  
D. Briggs
Keyword(s):  
Simple Model ◽  
Electric Field ◽  
Polymer Film ◽  
Polymer Films ◽  
Strong Electric Field ◽  
Length Scales ◽  
Observed Behaviour

AbstractBy confining a polymer film between two electrodes one of which is solid but thin enough to be flexible, a characteristic lateral morphology is produced when a strong electric field is applied across the film. A simple model to describe the observed behaviour is presented which accounts for the length scales of the observed morphology. This model demonstrates that feature sizes ranging from microns to nanometers can be obtained through selective choice of key parameters.

Electrochemical Influence of Collagen Piezoelectric Effect in Bone Healing

2007 ◽  
Vol 544-545 ◽  
pp. 981-984 ◽  
Author(s):  
Karem Noris-Suárez ◽  
Joaquín Lira-Olivares ◽  
Ana M. Ferreira ◽  
Armando Graterol ◽  
Jose L. Feijoo ◽  
...  
Keyword(s):  
Electric Field ◽  
Bone Healing ◽  
Bone Growth ◽  
Piezoelectric Effect ◽  
Osteoblastic Activity ◽  
Electrical Stimuli ◽  
Biomimetic Deposition

Bone healing and growth are controlled by the rate of deposition of hidroxiapatite (HA). This process have been so far accredited to the work of osteoblasts, which are attracted by the electrical dipoles produced either by piezoelectricity, due to deformation of the bone, specially the collagen in it, or due to outside electrical stimuli. The present work shows that even without osteoblasts present, the piezoelectric dipoles produced by deformed collagen, can produce the precipitation of HA by electrochemical means, without catalyzer as in biomimetic deposition. These findings could clarify the contribution of osteoblasts in bone growth as compared to the electrochemical action by itself. Further studies ascertaining the osteoblastic activity due to the electric field are being advanced.

Experimental Study of Melt Electrospinning in Parallel Electrical Field

2011 ◽  
Vol 221 ◽  
pp. 111-116 ◽  
Author(s):  
Ming Feng Hao ◽  
Yong Liu ◽  
Xue Tao He ◽  
Peng Cheng Xie ◽  
Wei Min Yang
Keyword(s):  
Experimental Study ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Melt Spinning ◽  
Fiber Diameter ◽  
The Other ◽  
Electrical Field ◽  
Melt Electrospinning ◽  
Plate Area

In this paper, self-designed electrospinning equipment was used to make a series of electrospinning experiments with materials of polypropylene. The influences of the receiver area, the upper plate area, and the overlapping area between the receiver and the upper plate, on the melt spinning electric field, the spinning efficiency, and the fiber diameter, were investigated respectively. The results showed that when the other parameters were kept unchanged, with the increase of the receiver’s diameter, the electric field strength and spinning efficiency increased, and the fiber diameter increased at first and then decreased; the bigger the overlapping area between the receiver and the upper plate, the more stable the vertical spinning path.

Physicochemical and Electro-Rheological Characterization of Kaolinite / CMS / Silicone Oil Fluid

2010 ◽  
Vol 446 ◽  
pp. 33-41
Author(s):  
Thomas Reiss ◽  
Saoussen Laribi ◽  
Jean-Marie Fleureau ◽  
Jean Francois Tassin
Keyword(s):  
Electric Field ◽  
Yield Stress ◽  
Applied Electric Field ◽  
Silicone Oil ◽  
Rheological Behaviour ◽  
Rheological Characterization ◽  
Clay Particles ◽  
Observed Behaviour ◽  
Composite Nature

The aim of this study is to elaborate electro-rheological fluids based on kaolinite. the scientific characterization made it possible the identification of the composite nature and the checking of the intercalation of the polymer among the clay particles The rheological behaviour of the fluid depends on the electric field. A yield stress of the suspensions is observed, which increases with the applied electric field. An interpretation based on the different modes of association between the clay particles is proposed to account qualitatively for the observed behaviour.

On the K-dependence of the electrical field in a crystalline slab of oscillating charges

1981 ◽  
Vol 59 (7) ◽  
pp. 929-933 ◽  
Author(s):  
J. Grindlay
Keyword(s):  
Electric Field ◽  
Trigonometric Series ◽  
Wave Vector ◽  
Short Range ◽  
Electrical Field ◽  
Ewald Sum ◽  
Convergent Trigonometric Series ◽  
Short Range Part ◽  
Range Part

The short range part of the electric field of a crystalline slab array of oscillating charges (a) is related to the Ewald sum and (b) can be represented by a rapidly convergent trigonometric series involving the wave vector K. Values for the coefficients of the first few terms of this series are reported for lattice sites in the sc, fcc, bcc, NaCl, CsCl structures and the symmetry directions (1,0,0), (1,1,0), (1,1,1).

Sign in / Sign up

Export Citation Format

Share Document