Electrical measurements of immersed paint coatings on metal. II. Effect of osmotic pressure and ionic concentration of solution on paint breakdown

2007 ◽  
Vol 9 (2) ◽  
pp. 96-106 ◽  
Author(s):  
D. M. Brasher ◽  
T. J. Nurse
Keyword(s):  
Osmotic Pressure ◽  
Ionic Concentration ◽  
Electrical Measurements ◽  
Paint Coatings

The Sensitivity of the Pedal Ganglion of the Slug to Osmotic Pressure Changes

1956 ◽  
Vol 33 (3) ◽  
pp. 493-501
Author(s):  
G. A. KERKUT ◽  
B. J. R. TAYLOR
Keyword(s):  
Osmotic Pressure ◽  
Ionic Concentration ◽  
The Body ◽  
Bathing Solution ◽  
Pedal Ganglion ◽  
Bathing Medium ◽  
Rates Of Change ◽  
Fluid Concentration ◽  
Locke Solution ◽  
Pressure Changes

1. The effects of different dilutions of Locke solution on the electrical activity of the isolated pedal ganglion of the slug can be reproduced by adding different concentrations of glucose of mannitol to a given concentration of Locke. 2. This indicates that certain cells in the pedal ganglion are sensitive to the osmotic pressure of the solution and not its ionic concentration. 3. The preparation is sensitive to slow changes in the concentration of the bathing medium. The cells increased their activity when the bathing solution was slowly changed from 0.7 Locke to 0.6 Locke, the change taking 43 min. This corresponds approximately to a change of 1% of the body fluid concentration over 4 min. Such rates of change are found in the normal intact animal. 4. The sensitivity of the preparation compares well with that of the mammalian osmoreceptors.

scholarly journals Evaporation-induced stimulation of bacterial osmoregulation for electrical assessment of cell viability

2016 ◽  
Vol 113 (26) ◽  
pp. 7059-7064 ◽  
Author(s):  
Aida Ebrahimi ◽  
Muhammad Ashraful Alam
Keyword(s):  
Cell Viability ◽  
Osmotic Pressure ◽  
Electrical Conductance ◽  
Ionic Concentration ◽  
Droplet Microfluidics ◽  
Cell Multiplication ◽  
Bacterial Cells ◽  
Label Free ◽  
The Road ◽  
Viability Assay

Bacteria cells use osmoregulatory proteins as emergency valves to respond to changes in the osmotic pressure of their external environment. The existence of these emergency valves has been known since the 1960s, but they have never been used as the basis of a viability assay to tell dead bacteria cells apart from live ones. In this paper, we show that osmoregulation provides a much faster, label-free assessment of cell viability compared with traditional approaches that rely on cell multiplication (growth) to reach a detectable threshold. The cells are confined in an evaporating droplet that serves as a dynamic microenvironment. Evaporation-induced increase in ionic concentration is reflected in a proportional increase of the droplet’s osmotic pressure, which in turn, stimulates the osmoregulatory response from the cells. By monitoring the time-varying electrical conductance of evaporating droplets, bacterial cells are identified within a few minutes compared with several hours in growth-based methods. To show the versatility of the proposed method, we show detection of WT and genetically modified nonhalotolerant cells (Salmonella typhimurium) and dead vs. live differentiation of nonhalotolerant (such as Escherichia coli DH5α) and halotolerant cells (such as Staphylococcus epidermidis). Unlike the growth-based techniques, the assay time of the proposed method is independent of cell concentration or the bacteria type. The proposed label-free approach paves the road toward realization of a new class of real time, array-formatted electrical sensors compatible with droplet microfluidics for laboratory on a chip applications.

Rectal Absorption in the Desert Locust, Schistocherca Gregaria Forskål

1964 ◽  
Vol 41 (1) ◽  
pp. 69-80
Author(s):  
J. E. PHILLIPS
Keyword(s):  
Water Balance ◽  
Osmotic Pressure ◽  
Schistocerca Gregaria ◽  
Tap Water ◽  
Ionic Concentration ◽  
Malpighian Tubules ◽  
Desert Locust ◽  
Ionic Regulation ◽  
Rectal Absorption ◽  
Salt And Water Balance

1. The physiology of the excretory system and its role in salt and water balance have been studied in the desert locust, Schistocerca gregaria. 2. Collections and analyses were made of hindgut fluid (derived from the Malpighian tubules) and rectal fluid from locusts kept under various dietary régimes. 3. In starved locusts supplied with tap water very little fluid accumulates in the rectum, the output of the Malpighian tubules being almost completely reabsorbed. Relatively more salt than water is reabsorbed with the result that the rectal fluid attains a lower ionic concentration but higher osmotic pressure than the haemolymph. No fluid is voided. 4. In starved locusts supplied with hypertonic saline the rectum is distended with, fluid which has an osmotic pressure and ionic concentration considerably above that of the haemolymph. Very little fluid is voided. 5. Substantial elimination of fluid from the rectum occurs only in fed locusts, in association with the voiding of faeces. 6. These results are discussed in relation to the mechanism of osmotic and ionic regulation.

scholarly journals STUDIES OF THE INNER AND OUTER PROTOPLASMIC SURFACES OF LARGE PLANT CELLS

1943 ◽  
Vol 27 (2) ◽  
pp. 139-142 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Osmotic Pressure ◽  
Outer Surface ◽  
Plant Cells ◽  
Central Vacuole ◽  
Electrical Measurements ◽  
Surface Layers ◽  
Large Plant ◽  
Protoplasmic Surface

In Nitella, Chara, Hydrodictyon, and Valonia the inner and outer non-aqueous protoplasmic surface layers can be separated by certain plasmolytic agents which penetrate the outer surface more rapidly than the inner and hence raise the osmotic pressure of the protoplasm lying between them and cause it to increase in thickness by taking up water from the central vacuole. We may therefore conclude that the two surfaces differ. This idea is confirmed by earlier electrical measurements which show that when sap is placed outside the cell the chain See PDF for Structure produces an E.M.F. of several millivolts.

Metabolic Heat Dissipation and Internal Solute Levels of Artemia Embryos During Changes in Cell-Associated Water

1989 ◽  
Vol 145 (1) ◽  
pp. 263-282 ◽  
Author(s):  
J. S. GLASHEEN ◽  
STEVEN C. HAND
Keyword(s):  
Water Content ◽  
Osmotic Pressure ◽  
San Francisco ◽  
Heat Dissipation ◽  
Salt Lake ◽  
Dry Mass ◽  
Ionic Concentration ◽  
Organic Osmolytes ◽  
Cellular Dehydration ◽  
Metabolic Arrest

Embryos (cysts) of the brine shrimp Artemia enter a profound, yet reversible, state of metabolic arrest in response to cellular dehydration. We have monitored metabolic activity during this transition in embryos from the Great Salt Lake population by using microcalorimetric measurements of heat dissipation. Embryo hydration states can be precisely controlled by immersing cysts in solutions of varying ionic strength. When developing embryos were incubated in a 2.0moll−1NaCl solution, heat dissipation fell after 20 h to 1.13 mWg−1 dry mass, or 21 % of the value obtained when embryos were in control solutions of 0.25 moll−1. At higher ionic concentrations, heat dissipation declined to as low as 3% of control values. Recovery from dehydration was rapid. Energy flow increased to 135% of control values within 2h after returning cysts to the control medium. These metabolic transitions were correlated with embryo hydration levels measured across the same dehydration series. Total cyst water ranged from 112±2.6 gH2O 100 g−1 dry mass in 0.25 mol l−1 NaCl to 46±0.6 gH2O 100 g−1 dry mass in 5.0 mol l−1 NaCl. At the first point where heat dissipation was markedly suppressed (the 2.0 mol l−1 incubation), cyst water content was 72.8 ±0.9 gH2O 100 g−1 dry mass. This water content is similar to the ‘critical’ hydration level required to suppress carbohydrate catabolism and respiration in San Francisco Bay Artemia embryos (Clegg, 1976a,b). However, hydration characteristics of the two populations differed in solutions of lower ionic concentration. Total osmotic pressure in fully hydrated cysts was 1300 mosmol kg−1 H2O. A comprehensive inventory of the internal osmolytes indicated that inorganic ions (Na+, K+, Cl−, Mg2+, Ca2+, Pi) accounted for 21% of the osmotic activity and 1.48% of embryo dry mass. Organic solutes (trehalose, glycerol, ninhydrinpositive substances, and trimethylamine-N-oxide+betaine) contributed 60% of the osmotic pressure and 22% of the dry mass. Macromolecular components (protein, lipids, glycogen and DNA) were also quantified and formed the bulk of embryo mass. Taken together, 97.4% of the cyst dry mass was identified. At the cellular dehydration state promoting metabolic arrest, the concentrations of inorganic and organic osmolytes were 480–590 mmol kg−1 H2O and 1200–1480 mmol kg−1 H2O, respectively. The influence of these osmolyte concentrations is considered in the context of macromolecular assembly and metabolic control.

CBED study of low-temperature InP grown by gas source MBE

1993 ◽  
Vol 51 ◽  
pp. 810-811
Author(s):  
R. Rajesh ◽  
M.J. Kim ◽  
J.S. Bow ◽  
R.W. Carpenter ◽  
G.N. Maracas
Keyword(s):  
Low Temperature ◽  
Second Phase ◽  
Material System ◽  
Ion Milling ◽  
Electrical Measurements ◽  
Gas Source ◽  
Structural And Electrical Properties ◽  
The One ◽  
Lt Inp ◽  
Gas Source Mbe

In our previous work on MBE grown low temperature (LT) InP, attempts had been made to understand the relationships between the structural and electrical properties of this material system. Electrical measurements had established an enhancement of the resistivity of the phosphorus-rich LT InP layers with annealing under a P2 flux, which was directly correlated with the presence of second-phase particles. Further investigations, however, have revealed the presence of two fundamentally different types of precipitates. The first type are the surface particles, essentially an artefact of argon ion milling and containing mostly pure indium. The second type and the one more important to the study are the dense precipitates in the bulk of the annealed layers. These are phosphorus-rich and are believed to contribute to the improvement in the resistivity of the material.The observation of metallic indium islands solely in the annealed LT layers warranted further study in order to better understand the exact reasons for their formation.

Effect of MCl (M = Na, K) addition on microstructure and electrical conductivity of forsterite

2020 ◽  
Vol 92 (1) ◽  
pp. 10901
Author(s):  
Saloua El Asri ◽  
Hamid Ahamdane ◽  
Lahoucine Hajji ◽  
Mohamed El Hadri ◽  
Moulay Ahmed El Idrissi Raghni ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Sol Gel ◽  
Complex Impedance ◽  
Transmission Spectra ◽  
Electrical Measurements ◽  
Cation Type ◽  
Edx Analyses ◽  
The Fourier Transform

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740  °C and at 630–700  °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.

LABORATORY PRACTICE AT THE COURSE SPECIAL METHODS AND MEANS OF ELECTRICAL MEASUREMENTS IN THE CONTEXT OF ERASMUS ALIOT PROJECT

2018 ◽  
Vol 27 (103) ◽  
pp. 273-279
Author(s):  
E. J. Maevskaya, ◽  
◽  
O. О. Topuzanov, ◽  
V. L. Biliaiev, ◽  
S. N. Oginskaya, ◽  
...  
Keyword(s):  
Electrical Measurements ◽  
Laboratory Practice
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