scholarly journals Physiological Effects of a Hypotonic Environment

1940 ◽  
Vol 17 (4) ◽  
pp. 378-385
Author(s):  
G. P. WELLS ◽  
ISABEL C. LEDINGHAM ◽  
MARY GREGORY

1. The cilia of Pleurobrachia, Mytilus and Arenicola show inhibition, followed by accommodation, as a result of sudden downward or upward changes in the salinity of the bathing medium. 2. Variations in sensitivity occur between different species, and between different types of cilia in the same species. 3. When Mytilus gills are suddenly transferred from 100 to 30% sea water, they take up water very rapidly. Accommodation, as indicated by the mechanical activity, continues long after osmotic equilibrium has been reached. Therefore, accommodation is not an adjustment of the water content of the cell. 4. The results are discussed, and compared with those obtained on other types of contractile tissues.

2019 ◽  
Vol 9 (2) ◽  
pp. 42-46
Author(s):  
Nuzlya Ramadhana

In the cultivation of milkfish, water quality is very concerned about in order to minimize fish mortality when cultivated. Several important factors in the cultivation of milkfish are the level of salt content in the water, temperature and pH. Currently, farmers monitor water quality manually by coming directly to see water quality. If there are dead fish, the cultivator will replace the new water. This will have an impact on fish production which will decrease. The milkfish pond uses brackish water for pond waters. The salt content is between the sea water content and the fresh water content. The grade level may change from season to season. This change is due to biological processes that occur in these waters as well as the interaction between pond waters and the surrounding environment. The results showed that the results of the design of the salt concentration monitoring system in the milkfish ponds that have been carried out using Arduino Uno, conductivity sensors, pH sensors, temperature sensors, wifi modules, Mi-Fi and Smartphones to access android applications. The results of testing the microcontroller functionality that have been made are in accordance with the design and are running well. The system designed to transmit information in the form of salinity values, pH sensors, temperature sensors and TDS values ??with sensor accuracy that is linear with measurement results using conventional measuring instruments with the highest error values ??of 1.3%, 2.06%, 0.702% and 1.5 respectively. %.


1953 ◽  
Vol 1 (4) ◽  
pp. 225-244
Author(s):  
C.W.C. Beekom

The effect of sea floods on grassland is described and recommendations are made for the restoration of inundated grassland. Turf may be heavily damaged after +or- 4 weeks inundation with water containing more than 20 g. NaCl per 1. At lower salt concentrations Poa sp. and Trifolium repens are still badly damaged but other species, notably Lolium perenne, Agrostis stolonifera and Alopecurus sp., are capable of immediate regrowth after drainage. If grassland remains submerged during spring, rising temperatures promote active growth of the grasses followed by rapid decay caused by lack of oxygen. L. perenne is especially sensitive to submergence in warm weather. The dominant weed communities which appear on land on which the turf has been destroyed by sea-water are described. Reseeding is recommended as the quickest method of restoring badly damaged turf. The flooded land should first be thoroughly drained and then repeatedly harrowed to produce a shallow seed-bed on which herbage mixtures can be sown without the application of gypsum. Given average weather conditions, normal permanent grassland mixtures can be sown at salt concentrations, measured in spring, of up to 8-10 g. NaCl per 1. of moisture in the 5-20 cm. soil layer. At a salt concentration of about 10 g. per 1. measured in spring, L. perenne tends to dominate over other species while Poa sp. and T. repens suffer during the summer. At a salt concentration of 10-15 g. per 1. in spring, Poa sp. and T. repens should be omitted from seed mixtures, instead mixtures consisting of different types of L. perenne, Festuca pratensis and Phleum pratense should be sown. When the salt concentration of the soil moisture is higher that 15 g. per 1. in spring, sowing should be delayed and the weeds checked by mowing or grazing. Temporary rises of the salt concentration in dry symmers to 25 g. per 1. are tolerated by L. perenne, F. pratensis and Ph. pratense; similar rises up to 15-18 g. per 1. are tolerated by Poa sp. and T. repens.-W.J.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1978 ◽  
Vol 75 (1) ◽  
pp. 253-263
Author(s):  
J. E. TREHERNE ◽  
Y. PICHON

Reprint requests should be addressed to Dr Treherne. Sabella is a euryhaline osmoconformer which is killed by direct transfer to 50% sea water, but can adapt to this salinity with progressive dilution of the sea water. The giant axons were adapted to progressive dilution of the bathing medium (both in vivo and in vitro) and were able to function at hyposmotic dilutions (down to 50%) sufficient to induce conduction block in unadapted axons. Hyposmotic adaptation of the giant axon involves a decrease in intracellular potassium concentration which tends to maintain a relatively constant resting potential during adaptation despite the reduction in external potassium concentration. There is no appreciable change in the intracellular sodium concentration, but the relative sodium permeability of the active membrane increases during hyposmotic adaptation. This increase partially compensates for the reduction in sodium gradient across the axon membrane, during dilution of the bathing media, by increasing the overshoot of the action potentials recorded in hyposmotically adapted axons.


1979 ◽  
Vol 82 (1) ◽  
pp. 227-238
Author(s):  
M. ANDERSON

1. Intracellular recordings were made from the myoepithelial cells of the proventriculus of the marine polychaete worm Syllis spongiphila. Overshooting responses were elicited either by carbamylcholine added to the bathing medium or by directly applied intracellular current pulses. 2. In control artificial sea water (ASW) directly applied current pulses elicited regenerative responses of 68–119 mV in amplitude and 70–1800 ms in duration; these responses were associated with contractions of the myoepithelial cells. 3. Both pharmacologically and electrically elicited responses were reversibly abolished in Ca-free ASW and were unaffected by TTX or lowsodium solutions. Regenerative responses were elicited by direct intracellular stimulation in calcium-free ASW containing 1 mM-B2+ or 10 mM-Sr2+. Directly elicited responses were blocked reversibly in ASW containing calcium and 15-20 mM-Co2+ or 2.5-10 mM-Ni2+; they were blocked irreversibly in ASW containing calcium and 10 mM-La3+ or 100 μM-Zn2+. 4. Regenerative responses were elicited in Ca-free solutions containing 10-50 mM-Mn2+; these responses were not associated with contractions, were consistently of longer duration than responses elicited in control ASW, and were blocked by 20 mM-Co2+ or 10 mM-La3+. The overshoots of Mn2+ responses elicited in both Na-free and Na-containing, Ca-free solutions increased as the external concentration of Mn2+ was increased, with a slope of about 27 mV per 10-fold change in concentration of Mn2+. In Cacontaining solutions the slope was reduced to about 15mV per 10-fold change. 5. The results indicate that the myoepithelial cells generate Ca-spikes and that Mn2+ ions, in addition to Sr2+ and Ba2+ ions, pass through the Ca2+ channels of the myoepithelial cell membranes. Although Mn^ can replace Ca2+ in generating spikes, it apparently cannot replace Ca2+ in initiating contraction, and it many compete with Ca2+ in activating repolarization of the cell.


2020 ◽  
Vol 10 (8) ◽  
pp. 2753 ◽  
Author(s):  
Diana-Petronela Burduhos-Nergis ◽  
Petrica Vizureanu ◽  
Andrei Victor Sandu ◽  
Costica Bejinariu

This study aims to evaluate the corrosion resistance of carbon steel, used for carabiners manufacturing, coated with three different types of phosphate layer. The phosphate layers have been obtained by phosphate conversion coating with three different types of phosphate solutions: zinc-based solution, zinc-iron-based phosphate solution, and manganese-based phosphate solution. Additionally, the test was performed on zinc phosphate samples impregnated with molybdenum bisulfate-based oil and zinc phosphate samples further coated with a layer of elastomer-based paint. Considering the areas where the carabiners are used (civil engineering, navigation, oil industry, rescue operations, etc.), the corrosive environments studied are rainwater, Black Sea water, and fire extinguishing solution. The structure of the deposited layers was studied by scanning electron microscopy, while the interface structure between the alloy and corrosive environment was analyzed by electrochemical impedance spectroscopy. According to this study, the corrosion resistance of zinc-based phosphate coated samples and zinc/iron-based phosphate coated samples is higher than that of the studied carbon steel samples, despite the corrosion environment. Also, the most aggressive corrosion environment was the fire extinguishing solution.


2019 ◽  
Vol 11 (18) ◽  
pp. 2132 ◽  
Author(s):  
Agnieszka Faulkner ◽  
Claire E. Bulgin ◽  
Christopher J. Merchant

Coastal tidal effects on thermal plumes are investigated, exploiting remote sensing of two major coastal industrial installations. The installations use sea water as a coolant, which is then released back into coastal environments at a higher-than-ambient temperature, allowing the plume to be delineated from the ambient waters. Satellite-based thermal sensors observing the Earth at spatial resolutions of 90 and 100 m are used. It is possible to identify coastal features and thermal spatial distributions. This paper presents coastal tidal effects on detected plumes for two case studies: an intertidal embayment and open water exposure, both on the coast of the UK. We correlated the behaviours of thermal plumes using remotely sensed high resolution thermal imagery with tidal phases derived from tide gauges. The results show very distinct behaviours for the flood and ebb tides. The detected surface plume location was dependent on flow switching direction for the different types of tide. The detected surface area was dependent on the strength of the currents, with the largest area observed during the strongest currents. Understanding the dispersion of the plume is essential to influence understanding of any potential ecological impacts.


1999 ◽  
Vol 1999 (1) ◽  
pp. 1059-1063
Author(s):  
J. R. Bergueiro ◽  
A. Pita ◽  
M. A. Mayol ◽  
M. Rallo ◽  
J. López-Ruiz

ABSTRACT The authors have studied the biodegradation of an Arabian Light crude oil in sterile marine water by the CUES229 marine bacteria and the BIOLEN IG30 biologic activator, both in the presence and the absence of zeolites. Two different types of zeolites, a natural one (NZ) and an artificial one (Zestek56), were used to degrade the crude in the first experiment, arising a 20% increment in the degradation in the presence of natural zeolite when compared with a similar sample without zeolites, and a 9% in the artificial zeolite. Next set of experiment were made using reactors filled with 250 g of sea water and 0.02 g of zeolite and injecting CUES 229 bacteria up to 108 cells/ml. Samples were introduced in a shaker at 110 rpm and with regulated temperature at 30-C. Time evolution of the biodegradation was deduced from gas chromatography at the time intervals 1; 7 and 15 days. Later, a similar experiment, but with BIOLEN IG30, was also made. Biodegradation of aliphatic hydrocarbons was observed –after 15 days- until the C14 fractions, using zeolites plus Biolen IG30, and until the C18 fractions, using zeolite plus CUES 229 bacteria.


2019 ◽  
Vol 11 (12) ◽  
pp. 1684-1691 ◽  
Author(s):  
Sameera M. M. Mousally ◽  
Khadijah M. Al-Zaydi ◽  
Christian Petrier ◽  
Sana T. Arab ◽  
Moamen S. Refat

This paper deals with studying the sonochemical effect for water treatment purposes from the dibenzothiophene (DBT) as polycyclic aromatic sulfur hydrocarbons, one of the most impurities found in waste water coming from petroleum industry. A comparison for the results obtained from previous studies at 20 kHz and with our results at 352 kHz has been done. The influence of organic compounds in the water matrix, as a mixture with dibenzothiophene was also evaluated. The results indicated that some competition occurs in the case of the mixture Bisphenol A/dibenzothiophene. The results presented in this work depict the study of the interesting potential of ultrasound to treat different types of water contaminated with polycyclic aromatic sulfur hydrocarbons such as dibenzothiophene and comparison for the degradation profile with benzothiophene which explained previously by us.


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