scholarly journals Turkestan Cockroaches Avoid Entering a Static Electric Field upon Perceiving an Attractive Force Applied to Antennae Inserted into the Field

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 621
Author(s):  
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Hideyoshi Toyoda
Keyword(s):  
Electric Field ◽  
Attractive Force ◽  
Avoidance Behaviour ◽  
Static Electric Field ◽  
Free Electrons ◽  
Iron Plate ◽  
Electrostatic Induction ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Positively Charged

This study analysed the mechanism of avoidance behaviour by adult Turkestan cockroaches (Shelfordella lateralis Walker) in response to a static electric field (S-EF) formed in the space between a negatively charged polyvinyl chloride-insulated iron plate (N-PIP) and a grounded metal net (G-MN). The negative surface charge supplied to the iron plate by a voltage generator caused the G-MN to polarise positively via electrostatic induction. In the S-EF, the negative charge of the N-PIP created a repulsive force that pushed free electrons in the field toward the ground via the G-MN. When insects released in the space surrounded by the S-EF inserted their antennae into the S-EF, they pulled them back reflexively and moved backward. The analysis indicated that an electric current flowed transiently toward the ground when an insect inserted its antennae into the S-EF. The insect became positively charged via this discharge and was attracted to the opposite pole (N-PIP). In response to this attractive force, the insect pulled its antennae back quickly. The positive electrification caused by the removal of free electrons from the antenna tip triggered the avoidance behaviour.

scholarly journals Body Water-Mediated Conductivity Actualizes the Insect-Control Functions of Electric Fields in Houseflies

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 561 ◽  
Author(s):  
Yoshihiro Takikawa ◽  
Takeshi Takami ◽  
Koji Kakutani
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Arc Discharge ◽  
Body Water ◽  
The Body ◽  
Static Electric Field ◽  
Free Electrons ◽  
Water Conductivity ◽  
Control Functions ◽  
Negative Pole

In the present study, the relationship between body water loss and conductivity was examined in adult houseflies (Musca domestica). The events an insect experiences in an electric field are caused by the conductive nature of the insect body (i.e., movement of electricity within or its release from the insect). After houseflies were dehydrated, rehydrated, refrigerated, and frozen and thawed, they were placed in static and dynamic electric fields. Untreated houseflies were deprived of their free electrons to become positively charged and then attracted to the insulated negative pole in the static electric field and were exposed to corona and arc discharge from non-insulated negative pole in the dynamic electric field. There was no current in the bodies of dehydrated and frozen flies; hence, there was no attractive force or discharge exposure. In the remaining insects, the results were identical to those in the untreated control insects. These results indicated that the reduction of body water conductivity inhibited the release of electricity from the body in the static electric field and the discharge-mediated current flow through the body in the dynamic electric field. The insect was affected by the electric fields because of its conductivity mediated by body water.

Anionic poly(amino acid)s dissolve F-actin and DNA bundles, enhance DNase activity, and reduce the viscosity of cystic fibrosis sputum

2005 ◽  
Vol 289 (4) ◽  
pp. L599-L605 ◽  
Author(s):  
Jay X. Tang ◽  
Qi Wen ◽  
Andrew Bennett ◽  
Brian Kim ◽  
Catherine A. Sheils ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Aspartic Acid ◽  
Elastic Moduli ◽  
Histone H1 ◽  
Dnase Activity ◽  
Normal Airway ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Mucolytic Agents ◽  
Positively Charged

Bundles of F-actin and DNA present in the sputum of cystic fibrosis (CF) patients but absent from normal airway fluid contribute to the altered viscoelastic properties of sputum that inhibit clearance of infected airway fluid and exacerbate the pathology of CF. Previous strategies to remove these filamentous aggregates have focused on DNase to enzymatically depolymerize DNA to constituent monomers and gelsolin to sever F-actin to small fragments. The high densities of negative surface charge on DNA and F-actin suggest that the bundles of these filaments, which alone exhibit a strong electrostatic repulsion, may be stabilized by multivalent cations such as histones, antimicrobial peptides, and other positively charged molecules prevalent in airway fluid. This study reports that bundles of DNA or F-actin formed after addition of histone H1 or lysozyme are efficiently dissolved by soluble multivalent anions such as polymeric aspartate or glutamate. Addition of poly-aspartate or poly-glutamate also disperses DNA and actin-containing bundles in CF sputum and lowers the elastic moduli of these samples to levels comparable to those obtained after treatment with DNase I or gelsolin. Addition of poly-aspartic acid also increased DNase activity when added to samples containing DNA bundles formed with histone H1. When added to CF sputum, poly-aspartic acid significantly reduced the growth of bacteria, suggesting activation of endogenous antibacterial factors. These findings suggest that soluble multivalent anions have potential alone or in combination with other mucolytic agents to selectively dissociate the large bundles of charged biopolymers that form in CF sputum.

scholarly journals The passage of electricity through gaseous mixtures

1909 ◽  
Vol 82 (557) ◽  
pp. 500-517 ◽  
Keyword(s):  
Electric Field ◽  
Sulphur Dioxide ◽  
Current Theory ◽  
Molecular Aggregates ◽  
Gaseous Mixtures ◽  
Positive Ions ◽  
Positive Nucleus ◽  
Electrostatic Induction ◽  
Gas Molecules ◽  
Positively Charged

According to the current theory with regard to the production of ions in a gas subjected to the action of Röntgen rays, the act of ionisation consists in the expulsion of one or more corpuscles ( i. e . negatively charged units of electricity) from each of a certain number of molecules constituting the gas. The residual portion of each of these molecules is then said to be positively charged, although the nature of this charge is not in any way specified. There are thus present in the gas negatively charged nuclei ( i. e . the expelled corpuscles) and positively charged nuclei (the residual portions of the ionised molecules); owing to the forces due to electrostatic induction these nuclei attract several of the gas molecules, and the resulting molecular aggregates constitute the gaseous ions, both negative and positive. Suppose, now, that a mixture of two gases, e. g ., sulphur dioxide and oxygen, is subjected to the action of Röntgen rays; the positive nucleus would be of greater volume and mass in the case of sulphur dioxide than of oxygen, and in consequence it is quite possible that the resulting ions should show similar differences. Accordingly, if the two groups of positive ions move in the same electric field, a difference in velocities might thus reasonably be expected.

scholarly journals Hyaluronan/Diethylaminoethyl Chitosan Polyelectrolyte Complexes as Carriers for Improved Colistin Delivery

2021 ◽  
Vol 22 (16) ◽  
pp. 8381
Author(s):  
Natallia V. Dubashynskaya ◽  
Sergei V. Raik ◽  
Yaroslav A. Dubrovskii ◽  
Elena V. Demyanova ◽  
Elena S. Shcherbakova ◽  
...  
Keyword(s):  
Delivery System ◽  
Polyelectrolyte Complex ◽  
Multidrug Resistant ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Polyelectrolyte Complexes ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Positively Charged

Improving the therapeutic characteristics of antibiotics is an effective strategy for controlling the growth of multidrug-resistant Gram-negative microorganisms. The purpose of this study was to develop a colistin (CT) delivery system based on hyaluronic acid (HA) and the water-soluble cationic chitosan derivative, diethylaminoethyl chitosan (DEAECS). The CT delivery system was a polyelectrolyte complex (PEC) obtained by interpolymeric interactions between the HA polyanion and the DEAECS polycation, with simultaneous inclusion of positively charged CT molecules into the resulting complex. The developed PEC had a hydrodynamic diameter of 210–250 nm and a negative surface charge (ζ-potential = −19 mV); the encapsulation and loading efficiencies were 100 and 16.7%, respectively. The developed CT delivery systems were characterized by modified release (30–40% and 85–90% of CT released in 15 and 60 min, respectively) compared to pure CT (100% CT released in 15 min). In vitro experiments showed that the encapsulation of CT in polysaccharide carriers did not reduce its antimicrobial activity, as the minimum inhibitory concentrations against Pseudomonas aeruginosa of both encapsulated CT and pure CT were 1 μg/mL.

scholarly journals Emerging mechanisms of drug-induced phospholipidosis

2019 ◽  
Vol 401 (1) ◽  
pp. 31-46 ◽  
Author(s):  
Bernadette Breiden ◽  
Konrad Sandhoff
Keyword(s):  
Head Group ◽  
Lysosomal Storage ◽  
Vesicle Membrane ◽  
Drug Induced ◽  
Cationic Amphiphilic Drugs ◽  
Amphiphilic Drugs ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Positively Charged ◽  
Excessive Accumulation

Abstract Drug-induced phospholipidosis is a lysosomal storage disorder characterized by excessive accumulation of phospholipids. Its cellular mechanism is still not well understood, but it is known that cationic amphiphilic drugs can induce it. These drugs have a hydrophilic amine head group that can be protonated in the endolysosomal compartment. As cationic amphiphiles, they are trapped in lysosomes, where they interfere with negatively charged intralysosomal vesicles, the major platforms of cellular sphingolipid degradation. Metabolic principles observed in sphingolipid and phospholipid catabolism and inherited sphingolipidoses are of great importance for lysosomal function and physiological lipid turnover at large. Therefore, we also propose intralysosomal vesicles as major platforms for degradation of lipids and phospholipids reaching them by intracellular pathways like autophagy and endocytosis. Phospholipids are catabolized as components of vesicle surfaces by protonated, positively charged phospholipases, electrostatically attracted to the negatively charged vesicles. Model experiments suggest that progressively accumulating cationic amphiphilic drugs inserting into the vesicle membrane with their hydrophobic molecular moieties disturb and attenuate the main mechanism of lipid degradation as discussed here. By compensating the negative surface charge, cationic enzymes are released from the surface of vesicles and proteolytically degraded, triggering a progressive lipid storage and the formation of inactive lamellar bodies.

Charges on the surfaces of two chlorites

Clay Minerals ◽  
1981 ◽  
Vol 16 (4) ◽  
pp. 347-359 ◽  
Author(s):  
Angela A. Jones
Keyword(s):  
Surface Charge ◽  
Surface Area ◽  
Negative Charge ◽  
Total Surface Area ◽  
Acid System ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Ph Dependent ◽  
Positively Charged

AbstractTwo chlorites, sheridanite and clinochlore, have been examined to determine their surface charge characteristics. In order to increase their surface area and to produce a measurable surface charge, the chlorites were treated with 10−3m, 10−2m, and 10−1m HCl in 10−2m MgCl2 solutions. These treatments are shown not to alter the crystallinity of the chlorites and to produce a small pH-dependent negative charge which is not directly related to the total surface area. The clinochlore, (Si6.13Al1.84)(Al1.53FeIII0.53FeII0.18Mg9.52)O20(OH)16, is more readily attacked by the acids than the sheridanite, (Si5.43Al2.55)(Al2.90FeII0.05Mg8.86)O20(OH)16, and also produces material with greater surface area and pH-dependent, negative, surface charge. It is concluded that: (i) isomorphous substitutions in the lattice are not reflected in a permanent surface charge; (ii) the observed surface charge arises not only at the edges of the particles but also at points where the chlorite is predisposed to attack by acids; (iii) in the chlorite-acid system used, anions—probably mainly silicate—block positively charged sites.

scholarly journals A Simple and Scalable Method for the Preparation of Magnetite/Graphene Oxide Nanocomposites under Mild Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Tamás Szabó ◽  
Lilla Nánai ◽  
Dániel Nesztor ◽  
Balázs Barna ◽  
Ondřej Malina ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Room Temperature ◽  
Composition Range ◽  
Chemical Degradation ◽  
Wide Composition Range ◽  
Nanostructured Composite ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Harsh Conditions ◽  
Positively Charged

Nanostructured composite dispersions containing magnetic nanoparticles (MNPs) and graphene oxide (GO) lamellae have been prepared by a simple and easily scalable room temperature procedure. We show that, owing to the enormous surface area and negative surface charge developed in aqueous GO suspensions, large amounts of positively charged MNPs can be electrostatically attached to the layered host. This procedure is superior to many previous synthesis pathways because it exploits the charge-regulated adhesion of naked MNPs to GO resulting in the formation of stable and uniform nanocomposite materials in a wide composition range without any preliminary functionalization steps or harsh conditions that may lead to chemical degradation of the graphene-based nanosheets.

Assessment of Damage to Human Platelets after Aggregation and Other Injuries by Microscopic Observation and Estimation of Serotonin Uptake

1970 ◽  
Vol 23 (02) ◽  
pp. 261-275 ◽  
Author(s):  
G Zbinden ◽  
J. N Mehrishi ◽  
S Tomlin
Keyword(s):  
Platelet Aggregation ◽  
Electrophoretic Mobility ◽  
Human Platelets ◽  
Freezing And Thawing ◽  
Low Degree ◽  
Microscopic Evaluation ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Charged Macromolecules ◽  
5 Ht Uptake

SummaryThe severity of platelet damage induced by hyper- and hypotonic NaCl solutions and freezing and thawing was assessed by microscopic evaluation and measuring inhibition of 5-HT uptake. The same techniques were used to quantitate the effects of aggregating agents. The positively charged macromolecules PS, Poly-L und Poly-O reduced the net negative surface charge as determined by microelectrophoresis, caused platelet aggregation and inhibited 5-HT uptake. The damaging effects of Poly-L and Poly-O were more severe and more closely related to concentration than that of PS. The negatively charged macromolecules Poly-IC and NaPS increased the anodic electrophoretic mobility. Poly-IC and heparin caused a low degree of platelet clumping and no inhibition of 5-HT uptake. NaPS produced severe platelet damage with extensive clumping and complete inhibition of 5-HT uptake. Na laurate had the same effect, but did not alter electrophoretic mobility. ADP caused concentration-dependent platelet aggregation and inhibition of 5-HT uptake. The effects of ADP and NaPS were compared in agitated and non-agitated platelet samples containing identical concentrations of the 2 compounds. Agitation was found to increase the degree of platelet clumping and to reduce 5-HT uptake.

Surface charge and extracellular polymer of sludge in the anaerobic degradation process

1996 ◽  
Vol 34 (5-6) ◽  
pp. 309-316 ◽  
Author(s):  
X. S. Jia ◽  
Herbert H. P. Fang ◽  
H. Furumai
Keyword(s):  
Surface Charge ◽  
Growth Phase ◽  
Anaerobic Degradation ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Batch Experiments ◽  
High Substrate Concentration ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Extracellular Polymer

Changes of surface charge and extracellular polymer (ECP) content were investigated in batch experiments for three anaerobic sludges, each of which had been enriched at 35°C and pH 639-7.3 for more than 40 batches using propionate, butyrate and glucose, individually, as the sole substrate. Results showed that both ECP and the negative surface charge were dependent on the growth phase of microorganisms. They increased at the beginning of all batches when the microorganisms were in the prolific-growth phase, having high substrate concentration and food-to-microorganisms ratio. Both later gradually returned to their initial levels when the microorganisms were in the declined-growth phase, as the substrate became depleted. The negative surface charge increased linearly with the total-ECP content in all series with slopes of 0.0187, 0.0212 and 0.0157 meq/mg-total-ECP for sludge degrading propionate, butyrate and glucose, respectively. The change of surface charge for the first two sludges was mainly due to the increase of proteinaceous fraction of ECP; but, for glucose-degrading sludge, that could be due to the increases of both proteinaceous and carbohydrate fractions of ECP. The negative-charged nature of anaerobic sludge implies that cations should be able to promote granulation of anaerobic sludge.

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