scholarly journals The Effect of Pitressin and Pitocin on Water Balance in Bufo Regularis Reuss

1951 ◽  
Vol 28 (3) ◽  
pp. 374-384
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Water Absorption ◽  
Water Uptake ◽  
Marked Decrease ◽  
Urine Flow ◽  
Diuretic Effect ◽  
Posterior Pituitary ◽  
Antagonistic Action ◽  
Diuretic Action ◽  
Main Factor

1. In Bufo regularis the injection of either pitressin or pitocin is followed by an increase in the rate of water absorption through the skin, together with a marked decrease in urine flow. The response to pitressin is greater than that to pitocin. 2. The effect of pitocin in increasing water uptake can be attributed to the activity of the 5-10% of the pressor fraction which it contains. 3. A mixture of pitressin and pitocin has the same effect on water balance as a corresponding dose of pituitrin. Pitressin alone has a greater anti-diuretic effect than it has when pitocin is added. 4. Taking into account the antagonistic action of pitocin to pitressin it is possible to account for the anti-diuretic action of pitocin in terms of its pressor fraction content. 5. It is concluded that the pressor fraction is the main factor responsible for both the dermal and the renal components of the water-balance effect produced in B. regularis by injection of mammalian posterior pituitary extracts. This conclusion is discussed in relation to the findings of other workers.

Water Uptake and Moulting in Bufo Regularis Reuss

1951 ◽  
Vol 28 (3) ◽  
pp. 369-373 ◽  
Author(s):  
R. F. EWER
Keyword(s):  
Water Uptake ◽  
Urine Flow ◽  
Posterior Pituitary

1. In Bufo regularis Reuss moulting is accompanied by an increase in the rate of water uptake through the skin. An increase in urine flow is also observed, starting some time after the rate of water uptake has begun to increase. 2. No increase in rate of water uptake occurs following thyroxine feeding on 4 successive days. 3. The possibility that posterior pituitary activity is responsible for the observed increase in rate of water uptake during moulting is discussed.

The Effects of Posterior Pituitary Extracts on Water Balance in Bufo Carens and Xenopus Laevis, together with some General Considerations of Anuran Water Economy

1952 ◽  
Vol 29 (3) ◽  
pp. 429-439
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Xenopus Laevis ◽  
Water Uptake ◽  
Seasonal Variations ◽  
Biological Significance ◽  
Weight Increase ◽  
Posterior Pituitary ◽  
Large Weight ◽  
Water Economy ◽  
Diuretic Response

1. The effects of pitressin and pitocin on water balance in Bufo carens and Xenopus laevis have been investigated. Bufo carens is most sensitive to pitressin, and shows an increased water uptake together with a well-marked anti-diuretic response. Xenopus reacts equally to the two extracts by an increase in water uptake, but there is no anti-diuresis. 2. The effects of pitressin and pitocin in causing lymph accumulation and resorbtion of fluid from the bladder have been studied in Bufo regularis. Pitressin has the greater effect, and there are indications of seasonal variations in the magnitude of the response. 3. The normal rates of water uptake of B. regularis, B. carens and Xenopus laevis have been measured. The two species of Bufo take up water rapidly, but Xenopus does so much more slowly. After desiccation the water uptake of Bufo regularis increases very considerably. This does not occur in Xenopus. 4. There is a large weight increase after injection of posterior pituitary extracts in Bufo regularis and B. carens, but not in Xenopus laevis. The findings of other workers on the magnitude of the weight increase after posterior pituitary injections are summarized. 5. The results are discussed in relation to the identity of the active principles of the anuran posterior pituitary and to the biological significance of the responses.

The Effect of Pituitrin Injection on the Water Balance of Bufo Regularis Reuss

1950 ◽  
Vol 27 (1) ◽  
pp. 40-49
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Water Content ◽  
Water Uptake ◽  
Lymphatic System ◽  
Biological Significance ◽  
Body Water ◽  
Urine Flow ◽  
The Body ◽  
Excess Water

1. A method of cannulating the cloaca of Anura is described. 2. Using this method it is found that in Bufo regularis the increase in body water which follows pituitrin injection is the result of an increased rate of water uptake, together with a diminished urine flow. 3. The excess water is mostly retained in the lymph spaces, while the water content of the tissues of the body increases very little. 4. The bearing of these results on the problem of the identification of the substance or substances which elicit the amphibian water balance effect, and the biological significance of the organization of the anuran lymphatic system are discussed.

scholarly journals Enhancement of mechanical, thermal and water uptake performance of TPU/jute fiber green composites via chemical treatments on fiber surface

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Tuffaha Fathe Salem ◽  
Seha Tirkes ◽  
Alinda Oyku Akar ◽  
Umit Tayfun
Keyword(s):  
Water Absorption ◽  
Water Uptake ◽  
Mechanical Test ◽  
Fiber Surface ◽  
Melt Flow Index ◽  
Jute Fiber ◽  
Morphological Properties ◽  
Flow Index ◽  
Melt Flow ◽  
Treatment Type

AbstractChopped jute fiber (JF) surfaces were modified using alkaline, silane and eco-grade epoxy resin. Surface characteristics of jute fibers were confirmed by FTIR and EDX analyses. JF filled polyurethane elastomer (TPU) composites were prepared via extrusion process. The effect of surface modifications of JF on mechanical, thermo-mechanical, melt-flow, water uptake and morphological properties of TPU-based eco-composites were investigated by tensile and hardness tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test, water absorption measurements and scanning electron microscopy (SEM) techniques, respectively. Mechanical test results showed that silane and epoxy treated JF additions led to increase in tensile strength, modulus and hardness of TPU. Glass transition temperature (Tg) of TPU rose up to higher values after JF inclusions regardless of treatment type. Si-JF filled TPU exhibited the lowest water absorption among composites. Surface treated JFs displayed homogeneous dispersion into TPU and their surface were covered by TPU according to SEM micro-photographs.

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

scholarly journals Water uptake of various electrospun nonwovens

2020 ◽  
Vol 6 (3) ◽  
pp. 155-158
Author(s):  
Katharina Wulf ◽  
Volkmar Senz ◽  
Thomas Eickner ◽  
Sabine Illner
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Water Absorption ◽  
Water Uptake ◽  
Biomedical Applications ◽  
High Surface ◽  
Volume Ratio ◽  
Polymer Composition ◽  
Water Wetting ◽  
Morphology Changes

AbstractIn recent years, nanofiber based materials have emerged as especially interesting for several biomedical applications, regarding their high surface to volume ratio. Due to the superficial nano- and microstructuring and the different wettability compared to nonstructured surfaces, the water absorption is an important parameter with respect to the degradation stability, thermomechanic properties and drug release properties, depending on the type of polymer [1]. In this investigation, the water absorption of different non- and plasma modified biostable nanofiber nonwovens based on polyurethane, polyester and polyamide were analysed and compared. Also, the water absorption by specified water wetting, the contact angle and morphology changes were examined. The results show that the water uptake is highly dependent on the surface modification and the polymer composition itself and can therefore be partially changed.

Gastric emptying, absorption, and carbohydrate oxidation during prolonged exercise

1992 ◽  
Vol 72 (2) ◽  
pp. 468-475 ◽  
Author(s):  
N. J. Rehrer ◽  
A. J. Wagenmakers ◽  
E. J. Beckers ◽  
D. Halliday ◽  
J. B. Leiper ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Crossover Study ◽  
Water Absorption ◽  
Water Uptake ◽  
Prolonged Exercise ◽  
Carbohydrate Oxidation ◽  
O2 Consumption ◽  
Digestive Function ◽  
Jejunal Perfusion ◽  
Over Time

This study was designed to examine aspects of digestive function that may limit assimilation of water and oxidation of orally ingested carbohydrate (CHO) during exercise. Eight males completed a crossover study in which each cycled on four occasions for 80 min at 70% maximal O2 consumption. Beverage was consumed at 0, 20, 40, and 60 min. Beverages were water, 4.5% glucose (4.5G), 17% glucose (17G), and 17% maltodextrin (17MD). CHO beverages contained 20 meq/l NaCl and were 13C enriched to measure exogenous CHO oxidation. Gastric (beverage) volume was measured at 80 min. Water uptake was estimated by including 2H2O in the beverage and measuring 2H accumulation in blood. Jejunal perfusion tests were conducted at rest with the same subjects and beverages. In 60 min, 1,294 +/- 31 (SE) ml were ingested; at 80 min, volumes emptied with H2O (1,257 +/- 32 ml) and 4.5G (1,223 +/- 32 ml) were greater than with 17G (781 +/- 56 ml) and 17MD (864 +/- 71 ml; P less than 0.05). Total CHO oxidized was similar with all beverages, but there was a greater increase in exogenous CHO oxidation over time with 17G and 17MD than with 4.5G; 54, 19, and 18% of the CHO ingested with 4.5G, 17G, and 17MD, respectively, was oxidized. This represents 57, 32, and 27%, respectively, of the CHO emptied from the stomach. 2H accumulation in the blood was more rapid with H2O and 4.5G than with 17G or 17MD. Net jejunal water absorption was greater from 4.5G than from water. Net water absorption was also observed from 17MD, whereas net secretion was observed with 17G.(ABSTRACT TRUNCATED AT 250 WORDS)

Water Uptake and Embryonic Development in Eggs of Chorthippus Brunneus Thunberg (Saltatoria: Acrididae)

1969 ◽  
Vol 50 (2) ◽  
pp. 327-333
Author(s):  
F. MORIARTY
Keyword(s):  
Sodium Chloride ◽  
Embryonic Development ◽  
Water Absorption ◽  
Osmotic Pressure ◽  
Water Uptake ◽  
Water Loss ◽  
Chloride Solutions ◽  
Sodium Chloride Solutions ◽  
Close Relationship ◽  
Further Development

1. The pattern of water absorption by eggs of Chorthippus brunneus varies greatly between individuals. 2. The time at which water is absorbed does not have a close relationship with the stage of embryonic development. 3. Water absorption is not essential for prediapause development. 4. Eggs can only undergo blastokinesis and further development, after diapause is broken, if some water has been absorbed. 5. The rate of water loss or gain varies with the osmotic pressure of sodium chloride solutions. 6. Eggs which have started to absorb water appear to become desiccated more rapidly than eggs which have not.

Water absorption effect on the in-plane shear properties of jute–glass–carbon-reinforced composites using Iosipescu test

2018 ◽  
Vol 53 (21) ◽  
pp. 3033-3045 ◽  
Author(s):  
MA Abd El-baky ◽  
MA Attia
Keyword(s):  
Water Absorption ◽  
Water Uptake ◽  
Sea Water ◽  
Water Immersion ◽  
Cost Effective ◽  
Stacking Sequence ◽  
Plane Shear ◽  
Noticeable Effect ◽  
Shear Properties ◽  
Glass Carbon

The main objective of the present paper is to study the water absorption of jute–glass–carbon-reinforced epoxy composites and its subsequent effect on the in-plane shear performance of these composites. The effects of the reinforcement hybridization, stacking sequence and relative fabric amounts on the shear behavior of dry and wet conditioned composite specimens are reported and discussed. Composites have been fabricated in inter-ply configuration using the hand lay-up process. The prepared specimens have been subjected to distilled water and sea water immersion at room temperature for 60 days. Results indicated that water uptake of jute-reinforced composite and its hybrids with glass and/or carbon follows Fickian-like behavior. Water uptake induces a significant decrease in the in-plane shear strength. Hybridizing jute fabric with glass and/or carbon fabrics improves the in-plane shear properties of both dry and wet specimens. The stacking sequence and relative fabric amounts have a noticeable effect on the studied shear properties. Also, the hybrid composite with jute as facings and glass as core, JGJ, offers the most balanced set of properties on a cost-effective basis compared to the other studied hybrids.

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