Effect of water immersion on renin-aldosterone and renal handling in normal man

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.

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Effect of water-immersion stress on prostaglandin E2 in rat gastric mucosa

Gastroenterologia Japonica ◽

10.1007/bf02815803 ◽

1981 ◽

Vol 16 (3) ◽

pp. 236-241 ◽

Cited By ~ 18

Author(s):

Tetsuo Arakawa ◽

Kenzo Kobayashi ◽

Hajime Nakamura ◽

Shinji Chono ◽

Hiroaki Yamada ◽

...

Keyword(s):

Gastric Mucosa ◽

Prostaglandin E2 ◽

Water Immersion ◽

Effect Of Water ◽

Rat Gastric Mucosa

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Effect of Water Absorption Behaviour on Tensile Properties of Hybrid Jute-Roselle Woven Fibre Reinforced Polyester Composites

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.18.4.2021.02.0705 ◽

2021 ◽

Vol 18 (4) ◽

Author(s):

Agung Efriyo Hadi ◽

Tezara Cionita ◽

Deni Fajar Fitriyana ◽

Januar Parlaungan Siregar ◽

Ahmed Nurye Oumer ◽

...

Keyword(s):

Tensile Strength ◽

Water Absorption ◽

Fibre Composite ◽

Unsaturated Polyester ◽

Water Immersion ◽

Tensile Modulus ◽

Natural Fibre ◽

Jute Fibre ◽

Thickness Swelling ◽

Effect Of Water

Incorporating natural fibre as reinforcement in the polymer matrix has shown a negative effect since the natural fibre is hydrophilic. The natural fibre easily absorbs water which causes an effect on the mechanical properties of the composites. The objective of this paper is to investigate the water absorption behaviour of hybrid jute-roselle woven fibre reinforced unsaturated polyester composite and the effect of water absorption in terms of tensile strength and tensile modulus. The effect of hybrid composite on the thickness swelling will be tested. The fabrication method used in this study is the hand lay-up technique to fabricate 2-layer and 3-layer composites with layering sequences of woven jute (J)/roselle (Ro) fibre. The results of the study showed that pure roselle fibres for 2 and 3-layer composites have the highest water absorption behaviour 3.86% and 5.51%, respectively, in 28 days) as well as thickness swelling effect, whereas hybrid J-Ro and J-J-Ro composites showed the least water absorption (2.65% and 3.76%, respectively) in 28 days) in both the tests. The hybridisation between jute and roselle fibres reduced water absorption behaviour and improved the fibres dimensional stability. The entire composites showed a decreasing trend for both tensile strength and tensile modulus strength after five weeks of water immersion. Jute fibre composite hybridised with roselle fibre can be used to reduce the total reduction of both tensile strength and tensile modulus throughout the whole immersion period. Moreover, the tensile testing showed that jute fibre composite hybridised with roselle fibre have produced the strongest composite with the highest tensile and modulus strength compared to other types of composites. The hybridisation of diverse fibre reinforcements aids in minimising the composite water absorption and thickness swelling, hence reducing the effect of tensile characteristics.

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Effect of water immersion on the microtopography of the skin of chicken carcasses

Journal of the Science of Food and Agriculture ◽

10.1002/jsfa.2740330609 ◽

1982 ◽

Vol 33 (6) ◽

pp. 549-554 ◽

Cited By ~ 33

Author(s):

Connor J. Thomas ◽

Thomas A. McMeekin

Keyword(s):

Water Immersion ◽

Effect Of Water

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Effect of Water Immersion versus Air Insufflation on Gastroenterology Trainee Insertion Times With the Full Spectrum Endoscopy (FUSE) Non-variable Stiffness Colonoscope

The American Journal of Gastroenterology ◽

10.14309/00000434-201710001-00515 ◽

2017 ◽

Vol 112 ◽

pp. S272

Author(s):

Melissa Latorre ◽

Ahmad N. Bazarbashi ◽

David S. Lee

Keyword(s):

Water Immersion ◽

Variable Stiffness ◽

Full Spectrum ◽

Effect Of Water ◽

Air Insufflation

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Effect of water immersion on multi- and mono-metallic VMD

Forensic Science International ◽

10.1016/j.forsciint.2017.12.020 ◽

2018 ◽

Vol 283 ◽

pp. 118-127 ◽

Cited By ~ 6

Author(s):

Romain Steiner ◽

Andy Bécue

Keyword(s):

Water Immersion ◽

Effect Of Water

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Dissociation of Renin-Aldosterone and Renal Prostaglandin E during Volume Expansion Induced by Immersion in Normal Man

Clinical Science ◽

10.1042/cs0590055 ◽

1980 ◽

Vol 59 (1) ◽

pp. 55-62 ◽

Cited By ~ 3

Author(s):

M. Epstein ◽

M. D. Lifschitz ◽

R. Re ◽

E. Haber

Keyword(s):

Plasma Renin Activity ◽

Volume Expansion ◽

Water Immersion ◽

Plasma Renin ◽

Normal Subjects ◽

Plasma Aldosterone ◽

Renin Activity ◽

Prostaglandin E ◽

Plasma Aldosterone Concentration ◽

Normal Man

1. The relationship of the renin-angiotensin-aldosterone axis with renal prostaglandin E is complex. Although studies have suggested that these two hormonal systems respond to experimental manipulations in a parallel manner, their interdependence has not been assessed fully during volume expansion. Since studies have demonstrated that in normal man the central hypervolaemia induced by water immersion to the neck produces a prompt and profound suppression of plasma renin activity and plasma aldosterone concentration without concomitant alteration of plasma composition, immersion afforded a unique opportunity to assess simultaneously the effects of central hypervolaemia on plasma renin activity, plasma aldosterone concentration and prostaglandin E excretion. 2. Seven normal subjects were studied twice while in balance on a diet containing 10 mmol of sodium/day, 100 mmol of potassium/day: with indomethacin administration (50 mg given every 6 h for five doses) and without indomethacin. Urinary prostaglandin E excretion was measured hourly and plasma renin activity and plasma aldosterone concentration at 30 min intervals. 3. Immersion was associated with a marked suppression of plasma renin activity (59 ± 7%) and plasma aldosterone concentration (55 ± 3%) with a return to pre-study values during the recovery hour. Concomitantly, urinary prostaglandin E excretion increased from 4.7 to a peak of 10.9 ng/min. Although administration of indomethacin lowered the basal rate of urinary prostaglandin E excretion and plasma renin activity, it did not prevent the subsequent augmentation of urinary prostaglandin E or the suppression of plasma renin activity and plasma aldosterone during the subsequent 4 h of immersion. 4. These results demonstrate a dissociation of renin-aldosterone and prostaglandin E during hypervolaemia and suggest that whereas prostaglandin E may constitute one of the major determinants of renin release clinically and experimentally, these two hormonal systems can be dissociated from each other in response to central volume expansion in man.

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