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[Electron microscopic and histochemical examination of hepatocytes in rat embryos exposed to the effect of a static electric field].

Static electric field with intensity of 150-80 V/cm has no teratogenic and embryolethal effect on the rat embryos. However, it provokes disturbance of the morphofunctional state of embryo liver, causes destructive-dystrophic changes in the parenchyma cells, decreases the content of nucleic acids, induces disturbances of the membrane systems of mitochondria and other cell structures.

Animals↗
PubMed1981

Temporal variation of the static electric field inside an animal cage.

The temporal variation of a static electric field inside an animal cage was investigated with a newly developed small, simple field meter. The field inside the cage was found to be highly dependent on the surface conductivity of the dielectric material. As the surface of the cage became dirty because of animal occupancy, the static electric field inside it became considerably smaller from the moment the field was turned on. Clean cages also modified the static electric field inside them, the field decaying from an initial to a much lower value over several hours. The mechanism of field attenuation for both cases is surface leakage. Surface leakage for a clean cage takes place much more slowly than for a dirty cage. This was confirmed by measuring DC insulation resistance. To examine this phenomenon further, the field in a metal cage width high electrical conductivity was measured. The static electric field inside the metal cage was also found to be reduced. An improved cage design that avoids these problems, is suggested for the study of the biologic effects of static electric fields.

Animals↗
PubMed1987

Plastic ESR tubes: does static electricity affect the results?

Static electrical charges were applied to the inside and outside surfaces of plastic ESR tubes, and this had no demonstrable effect on the results of the test. A further study confirmed that the plastic apparatus gave identical results to the standard Westergren method using glass tubes.

Blood Sedimentation↗
PubMed1998

Static-electric field induction by a silicone cushion for the treatment of hypertrophic and keloid scars.

Silicone gel and silicone occlusive sheeting are widely used at present for the treatment of hypertrophic and keloid scars, without any scientific explanation as to their mode of action. In a recent paper the possibility was raised that static electricity generated by friction-activated silicone sheeting could be the reason for this effect, and that it can, with time, cause involution of hypertrophic and keloid scars. The objective of this study was to test this hypothesis and to observe whether a continuous and also an increased negatively charged static-electric field will shorten the treatment period. A device to implement these requirements gradually evolved over a 5-year period. A number of prototypes were tested until the final product was attained. Some of the patients in this study were treated initially with a silicone sponge inserted in the cushion. Later this version was changed to the final design described herein. A silicone cushion was developed with the purpose of increasing a negative static-electric charge to accelerate the regression process. The cushion is custom-made using a silicone occlusive sheeting envelope of 0.75-mm thickness, which does not deteriorate with use, and is partially filled with high viscosity silicone oil. Its edges are sealed, and its size is designed to extend a little beyond the scarred area. Static electricity readings, generated by activating the cushion by pumping action with the fingers, stretching or deforming the cushion, are invariably much higher when compared with those obtained with silicone occlusive sheeting and silicone gel sheeting. The interaction between the negatively charged ions of the cushion and the ionic charges of the tissue fluids may be the critical factor in achieving hypertrophic and keloid scars involution. Of the 30 patients enrolled in the study, 3 patients dropped out. Treatment with the silicone cushions yielded 63.3 percent cessation of itching and burning followed by pallor and flattening of the scar, some markedly so, over a few weeks to 6-month period. An additional 26.6 percent had their scars resolved in up to 12 months of treatment. Good contact of the cushion over the scar has been shown to be important in this clinical trial, and much creativity is needed for making elastic strap bindings that ensure this contact. The clinical trials extended over a 12-month period. Ten patients (33.3 percent) who had recalcitrant scars with little response to the use of the silicone cushion were given intralesional corticosteroid injections, in addition to the continued use of the cushion, resulting in a fairly rapid resolution of these scars over a period of months to a year.

Adolescent↗
PubMed1995

Failure to produce taste-aversion learning in rats exposed to static electric fields and air ions.

Taste-aversion (TA) learning was measured to determine whether exposure to high-voltage direct current (HVdc) static electric fields can produce TA learning in male Long Evans rats. Fifty-six rats were randomly distributed into four groups of 14 rats each. All rats were placed on a 20 min/day drinking schedule for 12 consecutive days prior to receiving five conditioning trials. During the conditioning trials, access to 0.1% sodium saccharin-flavored water was given for 20 min, followed 30 min later by one of four treatments. Two groups of 14 rats each were individually exposed to static electric fields and air ions, one group to +75 kV/m (+2 x 10(5) air ions/cm3) and the other group to -75 kV/m (-2 x 10(5) air ions/cm3). Two other groups of 14 rats each served as sham-exposed controls, with the following variation in one of the sham-exposed groups: This group was subdivided into two subsets of seven rats each, so that a positive control group could be included to validate the experimental design. The positive control group (n = 7) was injected with cyclophosphamide 25 mg/kg, i.p., 30 min after access to saccharin-flavored water on conditioning days, whereas the other subset of seven rats was similarly injected with an equivalent volume of saline. Access to saccharin-flavored water on conditioning days was followed by the treatments described above and was alternated daily with water "recovery" sessions in which the rats received access to water for 20 min in the home cage without further treatment. Following the last water-recovery session, a 20 min, two-bottle preference test (between water and saccharin-flavored water) was administered to each group. The positive control group did show TA learning, thus validating the experimental protocol. No saccharin-flavored water was consumed in the two-bottle preference test by the cyclophosphamide-injected, sham-exposed group compared to 74% consumed by the saline-injected sham-exposed controls (P < .0001). Saccharin-preference data for the static field-exposed groups showed no TA learning compared to data for sham-exposed controls. In summary, exposure to intense static electric fields and air ions did not produce TA learning as assessed by this particular design.

Air↗
PubMed1995

Artefacts due to static electricity in a dental school.

The diagnostic usefulness of radiographs is diminished by errors of film handling, and retakes mean increased radiation doses. Avoiding artefacts due to static electricity is part of a quality assurance programme. The number of types of artefacts originating from static electricity in the Department of Radiology, School of Dentistry, Copenhagen, were recorded over a five-week period with low temperatures and low air humidity. During the period 3137 intra-oral and 638 extra-oral films were processed by seven assistants and a number of trainees. A total of 48 artefacts on 47 extra-oral films was observed. The artefacts were classified into four types. Only one case of classical 'lightning' was found, while nine were of a hitherto undescribed type ('animals' or 'cactus flowers'). The most common type appeared as dots arranged in straight lines; their origin was obscure, but it was suspected that they were caused by the processing machine. The one typical 'lightning' case occurred on a Status-X film, consistent with the theory that friction may be a causative factor. Although individual frequencies varied, all the radiography assistants and trainees were associated with the artefacts recorded.

Artifacts↗
PubMed1975

A device for the complete elimination of static electricity in paraffin sectioning.

In paraffin sectioning static electricity is often induced by friction between the knife and the block. The section can be discharged by ionizing the air in the vicinity of the paraffin. This can be achieved by mounting a strip containing radioactive polonium near the microtome knife. This approach implies a certain radiological risk. An alternative solution is to apply a high electric field close to the knife. The latter method may offer hazards related to the high tension and production of ozone. In comparing the risks and benefits of the two methods we have concluded that the application of a high electric field offers less risks to people in the working area than the installation of a radioactive source. The costs of the two methods are of the same order.

Costs and Cost Analysis↗
PubMed1977

The arrhythmogenic effect of static electricity on the dog heart.

Seven dogs, three with surgically-induced acute myocardial infarction, were subjected to the effects of static electricity discharged from our fingertips onto the external end of a transvenous right ventricular pacemaker. Initiation of ventricular beats occurred regularly when shocks were perceptible to the generating person and, not infrequently, when energy levels were below perception. In one dog with myocardial infarction, ventricular fibrillation was clearly related to the static discharge. The data obtained in this study support the recommendations of the Electrical Safety Hazard committee that critical care areas not be carpeted in order to minimize static discharges. In addition to low static floor covering in these areas, one can reduce static charge by the use of foot coverings such as those worn in the operating room. We found that no static charge could be developed when wearing the expandable operating room "booties." Since static charges were transmitted through our fingertips, probably the best means of protecting the electrically sensitive patient against the hazard of static electricity is to instruct personnel to wear rubber gloves whenever direct contact with the external ends of a pacing catheter becomes necessary. Routinely, such exteriorized pacemaker ends should also be covered with a nonconductive substance.

Animals↗
PubMed1990

[Hygienic regulation of static electric field generated by devices with electron-ray tube].

When detecting and hygienically assessing the static electric field generated by the devices with a half-tone storage tube it is necessary to take account of the impact of a number of characteristics of field intensity ranging on the obtained results. Taking into consideration the above characteristics during the research permits to lower error in the derived values and approximate them to the characteristics affecting the organisms of those using devices with a half-tone storage tube.

Beta Particles↗
PubMed1975

[Mutagenic action of static electric fields on Drosophila melanogaster females].

The effect of the 24-hours' action of 1500 v/cm and 3300 v/cm static electric fields (SEF) on the non-disjunction and sex-linked recessive lethal mutations in Drosophila melanogaster females was studied. Both SEFs increased the frequency of sex-linked recessive lethals, that was shown to be independent of the boltage of the field. The action of SEF exerted on effect on the frequency of non-disjunction of X-chromosomes.

Animals↗
PubMed1976

Dielectric increment of low molecular weight RNA in dioxane after application of static electric fields.

A soluble RNA with a molecular weight between 15 000 and 23 000 was extracted from calf thymus and chromatographically purified. The RNA was slightly soluble in doxane (approx. 2.5 mug/ml) and RNA-dioxane solutions were used to fill a cell (452.02 pF capacitance) to which static electric fields of variable strength were applied. The dielectric permittivity of the solutions was measured at a fixed time interval after the application of the electric field. The RNA solutions showed a dielectric increment proportional to the strength of the applied field and to the RNA concentration. The existence of a hystersis effect was proven and the effect of the electric field on the RNA molecule might be related to a dielectric saturation phenomenon parallel to long-term changes of the molecule.

Animals↗
PubMed1980

Insulin-lecithin interaction in non-aqueous solvents and its change after application of a static electric field.

The interaction between dipalmitoyl lecithin and egg lecithin with insulin was studied in a non-aqueous solvent such as dioxane-chloroform (1:1) by dielectric constant measurements and absorption spectra. The electrostatic character of the interaction results from the dielectric measurements and the effect of an external application of a static electric field (F = 30 kV/cm) is apparently related to the strength of such an interaction. The different strength of interaction of insulin with the two types of lecithins results also from experiments with a two-phase system.

Animals↗
PubMed1997

Effects of a low-voltage static electric field on energy metabolism in astrocytes.

Mouse astrocytes (glial cells) in primary cultures were exposed to a low-voltage static DC electric field with no current flow and thus with no generation of magnetic fields. The electric field altered the rate of glycolysis, measured by 2-deoxyglucose accumulation. The magnitude and direction of this effect depended on the polarization of the field and the applied voltage. The maximum effect was an increase of approximately 30%, which occurred with field across the cells at an intensity that can be calculated to be 0.3 mV/cm or less. Reversal of the polarization converted the stimulation to a small but statistically significant inhibition.

Animals↗
PubMed1997

Assessment of errors in static electrical impedance tomography with adjacent and trigonometric current patterns.

In electrical impedance tomography (EIT), difference imaging is often preferred over static imaging. This is because of the many unknowns in the forward modelling which make it difficult to obtain reliable absolute resistivity estimates. However, static imaging and absolute resistivity values are needed in some potential applications of EIT. In this paper we demonstrate by simulation the effects of different error components that are included in the reconstruction of static EIT images. All simulations are carried out in two dimensions with the so-called complete electrode model. Errors that are considered are the modelling error in the boundary shape of an object, errors in the electrode sizes and localizations and errors in the contact impedances under the electrodes. Results using both adjacent and trigonometric current patterns are given.

Computer Simulation↗
PubMed1978

[Neutralization of static electricity charged on running vinyl chloride sheet by the use of soft beta-ray sources (author's transl)].

The feasibility of 147Pm and 3H beta-ray sources as static eliminator was experimentally investigated. A sheet of vinyl chloride of 0.1 mm in thickness was used as an example of electrified materials. Its surface charge densities before and after beta-ray neutralization were measured as the function of electrostatic charge changing the speed of the sheet and the distance between the beta-ray source and the sheet. With a 147Pm beta-ray source of 200mCi in effective activity, almost complete neutralization was found for the sheet with the charge density less than 6 X 10(-6) C/m2 running at the speed of 0.18 m/s. In the case of the running speed of 0.5 m/s frequently used in industry, the electrostatic charge below 3 X 10(6) C/m2, where corona discharger is not so effective, was also perfectly eliminated. It was found that the optimal distance between the beta-ray source and the sheet was 10 cm in the case of 147Pm. The use of 3H beta-ray source of 1 Ci was not satisfactory. These results demonstrate that 147 Pm beta-ray source operates most efficiently as static eliminator when the charge density of material and/or its moving speed is not high.

Chemical Phenomena↗
PubMed1994

Quasi-static electric field in a cylindrical volume conductor induced by external coils.

An expansion technique based on modified Bessel functions is used to obtain an analytical solution for the electric field induced in a homogeneous cylindrical volume conductor by an external coil. The current in the coil is assumed to be changing slowly so that quasi-static conditions can be justified. Valid for any coil type, this solution is ideal for fast computation of the induced electric field at a large number of points. Efficient implementation of this method in a computer code is described and numerical results are presented for a perpendicular circular coil and a tangential double-square coil.

Electric Conductivity↗