Mechanisms Of Water Retention Research Articles

コーティングカラーの流動特性に関する研究 第３報 コーティングカラーの新しい保水性測定法の開発

A new method for evaluating water retention and dewatering behavior of coating colors by base paper is proposed by developing an apparatus to measure the amount of absorbed liquid as a function of time. The device is composed of an upper chamber containing coating color and a lower chamber containing water, the two being separated by a flexible plastic foil. The water in lower chamber is connected to a measuring glass capillary. The paper sample was attached to a plastic plate by double sided-sticking tape and was placed on the filter surface at the top of the upper chamber. Dewatering from coating color was measured by tracing the movement of meniscus in the capillary with automatic optical detector. The movement of meniscus was converted to the amount of dewatering, which was then analyzed by personal computer. The result of this method was compared with those of the conductivity method. The features of dewatering curve were dependent on the type and particle size of pigments, the type and amount of soluble binders.Dewatering behavior of coating color was found to be sensitive to dispersion state of the pigment and pH of the color. Thus the present method proved to be effective for directly and automatically evaluate dewatering phenomena of coating color by base paper. This method is superior to the conductivity method because of higher reproducibility and directness of the measurement, thus providing direct and useful information about water retention mechanism of coating colors.

Mechanism of dehydration and intumescence of soluble silicates

The properties and structure of films prepared from solutions of potassium silicate were studied by thermal analysis, IR spectroscopy, and X-ray diffraction. Various SiO2:K2O molar ratios from 2.55 to 4.72 were prepared and studied to determine the effect of molar ratio on the hygroscopic nature, solubility, and intumescence. The results provided insight into the physical structure, and mechanism of water absorption of the potassium silicate films. The molar ratio has a profound effect on the solubility, water absorption, and intumescence of the potassium silicate film. The primary mechanism of water absorption and retention is by ionic hydration. Decrease in the ionic hydration driving force as the molar ratio is increased results in decreasing solubility. Since intumescence results from the release of water vapour, the degree of intumescence decreases as the amount of ionically bonded water decreases with increase in molar ratio.

団粒性用土 「赤玉」 の水分保持機能について

「赤玉」 は団粒性用土であるため, 排水性が良く, しかも団粒中の微細間隙によって保水能力が優れているといわれている。 本研究では, 一般的にいわれている 「赤玉」 の性質を確認するため, 団粒状態とその団粒を練りつぶしたペースト状態での水分保持機能を比較検討した。 その結果, 団粒体は団粒間間隙が生じることにより, 一粒の団粒より間隙率が9%増加した。 ペースト体は液体水分の移動が大きいため, 団粒体より蒸発速度が早かった。 団粒体では, 液体水分の移動が極端に小さいことが予想されたが, 蒸発実験初期では液体水分の移動がかなり大きかったし, 液体水分の移動が極端に小さくなるのは永久しおれの水分量以下のときであった。

Total body water, total exchangeable sodium and potassium in patients with convalescent acute myocardial infarction one to two months after onset.

Total exchangeable sodium (Nae), potassium (Ke), and total body water (TBW) were measured by the multiple isotope dilution method, in 10 healthy subjects (normal), 10 patients with congestive heart failure (CHF), and 47 patients with acute myocardial infarction (AMI), 1-2 months after onset. According to Killip's classification, 29 patients with AMI were classified as class I, and 18 patients were classified as class II and III (referred to as class II & III). No differences were found in plasma and urine sodium and potassium concentrations. By the multiple isotope dilution method, significant elevations in Nae/BSA (body surface area) were observed in the following order: normal, class I, class II & III and patients with CHF. Compared with normal subjects, Nae/BSA and Nae/Ke were elevated in class I patients. Elevations of Nae/Ke and TBW/BSA in both class II & III patients with AMI and patients with CHF indicated severe cardiac impairment. Both Nae/BSA (p = -0.60) and Ke/BSA (p = 0.71) had negative and positive correlations with the left ventricular ejection fractions (EF) measured by catheterization in 20 patients with AMI. This indicates a major sodium and water retention mechanism due to impaired cardiac function in AMI. It is worth noting that conspicuous abnormalities in body fluid compositions, particularly in class I patients with AMI as well as class II & III, remained despite no evidence of cardiac failure.

Renal function abnormalities, prostaglandins, and effects of nonsteroidal anti-inflammatory drugs in cirrhosis with ascites: An overview with emphasis on pathogenesis

The ability of the kidneys to excrete sodium and free water is often impaired in patients with cirrhosis. Sodium retention is a sine qua non for ascites formation. The impairment of water excretion causes hyponatremia and hypo-osmolality. In addition, these patients frequently have functional renal failure caused by intense renal vasoconstriction. The renin-angiotensin-aldosterone system and the sympathetic nervous system, which are activated in most cirrhotic patients with ascites, and a nonosmotic hypersecretion of antidiuretic hormone are important mechanisms of sodium and water retention. Angiotensin II and sympathetic nervous activity may also be involved in the pathogenesis of functional renal failure. The renal production of prostaglandins is increased in cirrhotic patients with ascites as a homeostatic response to antagonize the vascular effect of endogenous vasoconstrictors and the tubular action of antidiuretic hormone. Nonsteroidal anti-inflammatory drugs should, therefore, be administered with caution in these patients because they may induce acute renal failure and water retention. Although sulindac inhibits the renal synthesis of prostaglandins in cirrhotic patients with ascites, it appears to have less effect on renal function than do other nonsteroidal anti-inflammatory drugs administered to these patients.

Differential scanning calorimetry analysis of novolak-based photoresists

Differential scanning calorimetry analysis has been used to characterize a number of novolak resins, photoactive compounds and novolak-based photoresists. In the course of our investigation, insight was gained into the water retention mechanisms involved in novolak-based compounds, i.e., water molecules leave the polymer network in a two-step drying process: one below and another above glass transition temperature. A preliminary physical treatment of the samples to be analyzed is proposed and ensures simultaneous measurement of the glass transition temperature signal and the exothermic peak from the photoactive compound. The thermal signatures of various commercial photoresists have been obtained using this technique.

Skin water uptake and renal function in the toad

1. 1. Water balance in the toad Bufo marinus ictericus was studied by evaluating cutaneous water uptake and renal excretion. 2. 2. The permeability of the skin to water was 78 ± 6 nl min −1 cm −2 atm −1 in 60 toads anaesthetized by chloralose and preincubated in water for 3 hr. Injection of Ringer's solution did not reduce the water uptake by the skin, while hemorrhage, or injection of vasopressin, or oxytocin approximately doubled the rates of water transport. In vivo values of skin water permeability were similar to those observed in vitro. 3. 3. The renal parameters of the water balance were significantly reduced by hemorrhage and by injection of vasopressin. Injection of Ringer's solution promoted a significant increase of the urinary flow and osmolar clearance. 4. 4. It is suggested that the fight against water deprivation could proceed initially by the triggering of the urinary mechanisms of water retention, while the increase of the skin water permeability would occur in a later stage.

Urinary antidiuretic hormone excretion during mechanical ventilation and weaning in man.

The authors measured antidiuretic hormone (ADH) excretion and renal and cardiovascular function in eight patients with flail chest during four ventilatory conditions: continuous positive-pressure ventilation (CPPV), intermittent positive pressure ventilation (IPPV), spontaneous breathing with continuous positive airway pressure (CPAP) and spontaneous breathing (SB). Each condition was maintained for six to eight days. ADH excretion was significantly greater during CPPV (181 +/- 14 ng/24 h, mean +/- SE) than during IPPV (86 +/- 10), CPAP (181 +/- 14 ng/24 h, mean +/- 6). Free-water clearance was more negative during mechanical ventilation than during CPAP and SB, resulting in significant fluid retention during CPPV and IPPV (440 +/- 88 and 547 +/- 70 ml/day) and a negative water balance during SB (-154 +/- 80 ml/day). Arterial and central venous pressures and cardiac output (measured in four patients) did not change significantly among ventilatory conditions. It is concluded that ADH excretion is increased during CPPV, and this could represent one possible mechanism of water retention with this type of ventilation.

Mechanism of sodium and water retention in rats with experimental heart failure

Mechanism of sodium and water retention in rats with experimental heart failure. High output heart failure was produced in male rats by placing an aorta-to-vena cava (A-V) fistula distal to the renal arteries. Rats with an A-V fistula developed sustained salt retention, peripheral edema and ascites within 10 to 20 days after the operation. The urinary excretion of sodium was significantly lower in the A-V rats as compared to the control rats. No difference in total GFR, intrarenal distribution of filtration (Hanssen technique), PAH clearance or filtration fraction was found between the two groups. Also, fractional and absolute sodium reabsorption by the proximal tubule were not different for the two groups. Moreover, after acute saline loading, similar decreases in proximal tubular reabsorption occurred in controls and rats with an A-V fistula. However, A-V rats reabsorbed significantly more sodium and water by the loop of Henle than did the controls, both before and after volume expansion. The enhanced rate of reabsorption by the loop of Henle is thought to be one important factor which causes chronic salt retention and edema formation in A-V rats. Mecanisme de la retention d'eau et de sodium chez les rats atteints d'insuffisance cardiaque experimentale. Une insuffisance cardiaque a debit eleve est produite chez des rats mâles par la mise en place d'une fistule aorto-cave distale par rapport aux arteres renales. Chez ces rats apparaissent dans les dix jours qui suivent l'intervention, une retention d'eau et de sel prolongee, des oedemes peripheriques et une ascite. L'excretion urinaire du sodium est significativement inferieure chez les rats porteurs de fistules pas comparaison avec des controles. Aucume difference autre les deux groupes n'a ete trouvee en ce qui concerne le debit global de filtration glomerulaire, la distribution intra-renale des filtrations (technique de Hanssen), la clearance du PAH et la fraction filtree. De plus la reabsorption fractionnelle et absolve du sodium pas le tube proximal n'etait pas differente dans les deux groupes. Enfin, apres une surcharge en sel aigue, une inhibition similaire de le reabsorption tubulaire proximale a ete observee dans les deux groupes. Cependant, les rats porteurs de fistule reabsorbent significativement plus de sodium et d'eau dans l'anse de Henle que ne le font les controles, ceci avant et apres expansion. L'augmentation du debit de reabsorption par l'anse de Henle est probablement un facteur important de la retention chronique de sel et de la formation d'oedemes chez les rats porteurs d'une fistule.

The Mechanisms of Salt and Water Retention in Cardiac Failure

The congestion that is the clinical hallmark of most cases of cardiac failure begins with the development of a decrement in the heart's pumping competence and eventuates in edema and ascites. Between these end points is a complex of hemodynamic, hormonal, metabolic, and electrolytic abnormalities, many of which represent vain attempts to compensate for the underlying cardiac deficiency.

Treatment of edema with cation exchange resins, including certain hormonal observations.

Excerpt The use of ion exchange resins was suggested by Segal et al.2for control of gastric acidity and by Dock3for treatment of cardiac edema. The background and theory of ion exchange by resins i...

Electrolyte disturbances in congestive heart failure.

ras 44.2 mg. per minute. The mean filtration fraction, which is an expression of the glomerular filtration in relation to the renal plasma flow (G:F./R.P.F.) showed a definite increase from the normal of 17.4 per cent to 40.5 per cent in decompensated patients. This increase in the filtration fraction has been explained in the current concept as being a result of efferent arteriolar constriction, which, by increasing the hydrostatic pressure within the glomerular capillaries, would force a greater filtration from the blood during its flow through these structures. 4 That there may be impair­ ment of tubular function is suggested by a measurable decrease in the tubular excretory capacity. Normally, sodium is believed to be reabsorbed from the tubules in 2 phases: (1) an obligatory phase in the proximal tubule and (2) a facultative phase in the distal tubule. The former accounts for reabsorption of approximately 85 per cent of the filtered sodium. 6 With decreased glomerular filtration in con­ gestive heart failure there is a great reduction in tubular sodium load. This apparently results in increased reabsorption of sodium in the obligatory phase, either because of the decreased sodium load or because of malfunction of the tubular apparatus. Some observers believe that increased tubular reabsorption occurs in the distal tubule, also, and contributes further to the total retention of sodium. Other factors in the mechanism of sodium and water retention remain to be evaluated. There is increasing evidence that the pituitary and adrenal glands

The osmotic theory of eclampsia and the mechanism of water retention.

The osmotic theory of eclampsia and the mechanism of water retention.

Mechanisms of salt and water retention in heart failure

Mechanisms of salt and water retention in heart failure

Mechanisms of salt and water retention in heart failure

The concept is proposed that edema in heart failure is caused by retention of salt and water produced by a diminished ability of the kidney to excrete salt and water. This disturbance in the kidney is the result of an inadequate cardiac output which is both relatively and absolutely reduced in patients who have chronic cardiac edema at rest, and is relatively reduced as compared with general or specialized tissue demands in other cardiac subjects with edema, i.e., those who fail with exertion, hyperthyroidism, anemia or beri-beri, and who may have a normal or elevated resting cardiac output. The inadequate cardiac output, through one or more mechanisms, causes the kidney to excrete less salt and water. It also produces a reduction in renal plasma flow and filtration rate by a contraction of the efferent arterioles of the kidney effected by some humoral substance. The reduced filtration rate corresponds closely to the reduction in sodium excretion and evidence is presented which indicates that the lowered filtration rate may be one of the causes of the reduction in sodium excretion. In advanced stages of heart failure the reduction in salt and water excretion is probably produced by at least two other means—the adrenal cortex is definitely stimulated and the pars intermedia of the pituitary probably also plays a part. Much work needs to be done to evaluate the role of these various factors both in renal hemodynamics and sodium excretion. Too little is known of the effect of changes in the intracellular electrolytes on edema formation and cardiac physiology to warrant any speculation as to the part taken by them.

TRANSPIRATION AS INFLUENCED BY OSMOTIC CONCENTRATION AND CELL PERMEABILITY

TRANSPIRATION AS INFLUENCED BY OSMOTIC CONCENTRATION AND CELL PERMEABILITY