The Evaporation of Water from Helix Aspersa

1964 ◽  
Vol 41 (4) ◽  
pp. 759-769
Author(s):  
JOHN MACHIN
Keyword(s):  
Water Content ◽  
Water Loss ◽  
Vapour Pressure ◽  
Freezing Point ◽  
Muscular Activity ◽  
Helix Aspersa ◽  
Distilled Water ◽  
Atmospheric Conditions ◽  
Evaporative Water ◽  
Dry Air

1. Observations of intact specimens of Helix aspersa together with experiments with isolated skin preparations are described. 2. Under normal atmospheric conditions increases in haemocoelic pressure, probably due to general muscular activity, are sufficient to maintain the superficial mucous coating of the skin. 3. Under conditions of rapid water loss more intense muscular undulations serve to spread mucus which collects in the grooves to more exposed areas of the skin. 4. The water content, the rate of water loss in dry air, the equilibrium in saturated air and depression of freezing point of isolated mucus samples have been measured. 5. The vapour pressure of mucus has been shown to be within 0.4% of that of distilled water under the same conditions. 6. The significance of the above findings is discussed in relation to evaporative water loss and water uptake of an intact snail.

Studies on the water economy of some Australian frogs.

1965 ◽  
Vol 13 (2) ◽  
pp. 317 ◽  
Author(s):  
MR Warburg
Keyword(s):  
High Temperatures ◽  
Water Uptake ◽  
Water Loss ◽  
Vapour Pressure ◽  
Arid Regions ◽  
Vapour Pressure Deficit ◽  
Evaporative Water ◽  
Dry Air ◽  
Reduced Water ◽  
Semi Arid

The rate of evaporative water loss of several species of frog found in Australia and their ability to survive at high temperatures were studied at various temperatures in both dry and in humid air, and at constant vapour pressure deficit. The species studied were: Bufonidae, Bufo marinus (L.); Leptodactylidae, Crinia signifera Girard, Pseudophryne bibroni Gunther, Limnodynastes tasmaniensis Gunther, L. dorsalis (Gray), L. ornatus (Gray), Neobatrachus pictus Peters, N. centralis (Parker); Hylidae, Hyla ewingi (Dumeril & Bibron) and H. rubella Gray. To a certain extent, the trend for increased adaptation to terrestrial conditions follows the trend for reduced water loss. The rate of water uptake after dehydration is greatest in the burrowing frogs inhabiting arid and semi-arid regions. Survival at high temperatures in dry air was found to be a good criterion for judging the degree of adaptation of these frogs to life in arid regions.

Changes in specific airway resistance during prolonged breathing of moist air

1970 ◽  
Vol 48 (9) ◽  
pp. 592-597 ◽  
Author(s):  
G. Norris Melville ◽  
W. T. Josenhans ◽  
W. T. Ulmer
Keyword(s):  
Relative Humidity ◽  
Water Content ◽  
Water Loss ◽  
Healthy Subjects ◽  
Airway Resistance ◽  
Tap Water ◽  
Distilled Water ◽  
Moist Air ◽  
Specific Airway Resistance ◽  
Water Elimination

Effects of increased water content of inspired air at 21–38 °C on specific airway resistance (sRaw) in 107 healthy subjects were measured with a body plethysmograph. Mean sRaw increased insignificantly at 23 °C with 92% relative humidity (water content, 20.7 g∙m−3) for up to 71 h but became significant at 6 h with water content 25 g∙m−3. Increases were greater when evaporated tap water was inhaled than when distilled water was used. It is postulated that the increase in sRaw is due to mucosal swelling and to contaminants in tap water. A theory of respiratory "water elimination" is proposed to replace the concept of respiratory water loss.

scholarly journals Airway Surface Liquid Osmolality Measured Using Fluorophore-Encapsulated Liposomes

2001 ◽  
Vol 117 (5) ◽  
pp. 423-430 ◽  
Author(s):  
Sujatha Jayaraman ◽  
Yuanlin Song ◽  
A.S. Verkman
Keyword(s):  
Epithelial Cells ◽  
Water Loss ◽  
Airway Epithelial Cells ◽  
Evaporative Water Loss ◽  
Airway Surface Liquid ◽  
Airway Epithelial ◽  
Evaporative Water ◽  
Dry Air ◽  
Surface Liquid ◽  
Sulforhodamine 101

The airway surface liquid (ASL) is the thin layer of fluid coating the luminal surface of airway epithelial cells at an air interface. Its composition and osmolality are thought to be important in normal airway physiology and in airway diseases such as asthma and cystic fibrosis. The determinants of ASL osmolality include epithelial cell solute and water transport properties, evaporative water loss, and the composition of secreted fluids. We developed a noninvasive approach to measure ASL osmolality using osmotically sensitive 400-nm-diam liposomes composed of phosphatidylcholine/cholesterol/polyethylene glycol-phosphatidylcholine (1:0.3:0.08 molar ratio). Calcein was encapsulated in the liposomes at self-quenching concentrations (30 mM) as a volume-sensitive marker, together with sulforhodamine 101 (2 mM) as a volume-insensitive reference. Liposome calcein/sulforhodamine 101 fluorescence ratios responded rapidly (<0.2 s) and stably to changes in solution osmolality. ASL osmolality was determined from calcein/sulforhodamine 101 fluorescence ratios after addition of microliter quantities of liposome suspensions to the ASL. In bovine airway epithelial cells cultured on porous supports at an air–liquid interface, ASL thickness (by confocal microscopy) was 22 μm and osmolality was 325 ± 12 mOsm. In anesthetized mice in which a transparent window was created in the trachea, ASL thickness was 55 μm and osmolality was 330 ± 36 mOsm. ASL osmolality was not affected by pharmacological inhibition of CFTR in airway cell cultures or by genetic deletion of CFTR in knockout mice. ASL osmolality could be increased substantially to >400 mOsm by exposure of the epithelium to dry air; the data were modeled mathematically using measured rates of osmosis and evaporative water loss. These results establish a ratio imaging method to map osmolality in biological compartments. ASL fluid is approximately isosmolar under normal physiological conditions, but can become hyperosmolar when exposed to dry air, which may induce cough and airway reactivity in some patients.

scholarly journals Hydrophilic Polymers and Wetting Agents Affect Absorption and Evaporative Water Loss

HortScience ◽  
1993 ◽  
Vol 28 (6) ◽  
pp. 633-635 ◽  
Author(s):  
Allyson M. Blodgett ◽  
David J. Beattie ◽  
John W. White ◽  
George C. Elliott
Keyword(s):  
Water Absorption ◽  
Water Content ◽  
Water Loss ◽  
Hydrophilic Polymers ◽  
Wetting Agent ◽  
Hydrophilic Polymer ◽  
Evaporative Water ◽  
Maximum Water ◽  
Maximum Water Content ◽  
Container Capacity

A plantless system using subirrigation was developed to measure water absorption and loss in soilless media amended with hydrophilic polymers, a wetting agent, or combinations of these amendments. Peat-perlite-vermiculite and bark-peat-perlite controls achieved 67% and 52% of container capacity, respectively, after 20 daily irrigation cycles. Maximum water content of amended media was 78% of container capacity. Adding only a hydrophilic polymer did not increase total water content significantly. Adding a wetting agent increased water absorption in both media. However, when hydrophilic polymer and wetting agent were present, the medium absorbed more water than with wetting agent alone. More extractable water was removed from media containing wetting agent. Water loss rate by evaporation was not affected significantly by medium, hydrophilic polymer, wetting agent, or any combination of these variables.

The Physiology of Excretion in the Cotton Stainer, Dysdercus Fasciatus Signoret

1965 ◽  
Vol 43 (3) ◽  
pp. 511-521
Author(s):  
M. J. BERRIDGE
Keyword(s):  
Water Content ◽  
Large Volume ◽  
Water Loss ◽  
Malpighian Tubules ◽  
Gut Contents ◽  
Osmotic Gradient ◽  
Rapid Rate ◽  
Evaporative Water ◽  
Cotton Stainer ◽  
Two Phases

1. The intestine of Dysdercus is discontinuous in the larval instars, and urine from the Malpighian tubules is therefore uncontaminated by gut contents. 2. Excretion has been studied during the fifth instar, which lasts 8 days. Feeding only occurs in the first 4 days, during which there is a marked fall in water content. In the last part of the instar, when the animal only drinks, the water content returns to its original level. 3. The urine of Dysdercus is always liquid. There is a rapid rate of excretion during the first half of the instar, but when feeding ceases there is no further micturition and urine is retained in the rectum. Therefore there are two phases of excretion, designated excretory and post-excretory phases respectively. 4. The rectal epithelium is incapable of reabsorbing water against an osmotic gradient. 5. The urine which is retained in the rectum during the post-excretory phase acts as a water store; evaporative water loss is balanced by withdrawing water from this reservoir. During the excretory phase, a large volume of liquid is lost via the excretory system, but the loss is made good by drinking.

Water Relations in an Insect, Thermobia Domestica

1972 ◽  
Vol 57 (2) ◽  
pp. 285-296
Author(s):  
A. Y. K. OKASHA
Keyword(s):  
Water Content ◽  
Water Relations ◽  
Water Loss ◽  
Uptake Mechanism ◽  
Dry Air ◽  
Thermobia Domestica ◽  
General Terms ◽  
Moulting Cycle ◽  
Percentage Water Content

1. The percentage water content of Thermobia can be increased by starvation. 2. After desiccation (3 days in dry air) the water content of starved insects is still above normal; yet such insects will take up water from a infsaturated atmosphere (83% R.H.). 3. The rate of water loss into dry air from starved insects is not dependent upon water content. 4. Both water content and rate of water loss remain constant throughout the moulting cycle. 5. In general terms the uptake mechanism is not dependent upon water content. 6. Severe starvation before desiccation seems to impair or inhibit the uptake mechanism.

scholarly journals Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals

2017 ◽  
Vol 284 (1867) ◽  
pp. 20171478 ◽  
Author(s):  
E. C. Eto ◽  
P. C. Withers ◽  
C. E. Cooper
Keyword(s):  
Water Vapour ◽  
Water Loss ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Water Vapour Pressure ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Water Vapour Pressure Deficit

Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars ( Melopsittacus undulatus ) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy.

scholarly journals ROUTES OF TRANSPIRATORY WATER LOSS IN A DRYHABITAT TENEBRIONID BEETLE

1991 ◽  
Vol 157 (1) ◽  
pp. 425-437 ◽  
Author(s):  
KARL ERIK ZACHARIASSEN
Keyword(s):  
East Africa ◽  
Water Permeability ◽  
Water Loss ◽  
Air Humidity ◽  
Evaporative Water ◽  
Dry Air ◽  
Dominant Component ◽  
Tenebrionid Beetle ◽  
Abdominal Surface ◽  
Respiratory Gases

Routes of evaporative water loss in the tenebrionid beetle Phrynocolus petrosus Gerstaecker from dry savanna in East Africa were investigated. The humidity of the air surrounding the abdomen, the air surrounding the head and pronotum and the air inside the subelytral cavity was varied independently, and the effects on organismal rate of water loss were observed. The rate of organismal water loss dropped when the humidity around the head and pronotum and inside the subelytral cavity increased. Saturation of these air compartments, which both exchange respiratory gases with the tracheae through the spiracles, reduced the organismal rate of water loss by more than 80%, even when the large abdominal surface was surrounded by dry air. The results indicate that the transcuticular water loss makes up only about 20% of the total transpiratory water loss in these beetles, i.e. transcuticular water permeability is very low. The results also indicate that the average air humidity inside the subelytral cavity of normal intact beetles is close to saturation. Water loss from the subelytral chamber is reduced accordingly, and appears to make up less than 10% of the total transpiratory water loss. The water loss over the pronotal spiracles amounts to about 70%, and is thus the dominant component of transpiratory water loss in these beetles.

Transpiration Through the Cuticles of Some Aquatic Insects

1956 ◽  
Vol 33 (1) ◽  
pp. 107-118
Author(s):  
M. W. HOLDGATE
Keyword(s):  
Critical Temperature ◽  
Water Loss ◽  
Aquatic Insects ◽  
Structural Basis ◽  
Distilled Water ◽  
Dry Air ◽  
Wide Range ◽  
Cuticular Permeability ◽  
Mineral Dusts ◽  
Water Gain

1. Measurement of the rate of water loss in dry air from ten species of aquatic insects, representing six orders, has shown that the cuticles are in all cases more permeable than are those of typical terrestrial species. There is, however, a wide range of permeability within the group. 2. The rate of water loss increases exponentially with temperature. There is no ‘critical temperature’. The steepness of the exponential relating transpiration and temperature is greatest in the least permeable examples. 3. Chloroform treatment produces a marked increase in water loss, but abrasion by mineral dusts has very little effect. 4. Adult specimens of ‘Notonecta obliqua’ immersed in distilled water gain weight at a rate which suggests that the cuticle is comparatively permeable under these conditions also. The rate of water uptake is increased by chloroform treatment. 5. The results support the general theory advanced by Holdgate and Seal (1955), but no sound interpretation of the structural basis of cuticular permeability can yet be advanced.

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