swelling

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swelling

an abnormal enlargement of a bodily structure or part, esp as the result of injury

Swelling

 

an increase in volume of solid bodies caused by their absorption of liquids or vapors from the environment. The capacity to swell is a characteristic property of bodies consisting of macromolecular compounds (polymers). Swelling is caused by diffusion processes, which are usually accompanied by solvation (the binding of a low-molecular-weight substance by a polymer).

A distinction is made between limited and unlimited swelling. In the first case the macromolecules are bonded fairly strongly, and swelling stops after having reached a certain limit. The swelled body retains its shape and a distinct boundary with the liquid phase. In the second case, mutual diffusion of the solvent and the polymer gradually leads to the disappearance of the interphase boundary between the swelling body and the liquid. Such swelling culminates in complete dissolution of the polymer. For example, limited swelling is exhibited by gel-like ion-exchange resins in water and by vulcanized rubber in benzene; unlimited swelling is exhibited by all polymers that are soluble in a particular solvent. In some cases, such as the gelatin-water system, limited swelling gives way to unlimited swelling with increasing temperature. Swelling is also a property of some minerals with a lamellar crystal lattice—for example, the montmorillonites. Upon swelling in water, such materials may undergo spontaneous dispersion, leading to the formation of highly disperse colloidal systems.

Swelling has wide use in industry and in everyday life. It frequently accompanies bonding of polymer materials, processing of polymers to produce various articles, production of rubber adhesives, and other processes, such as preparation of many foods and many natural processes (germination of seeds and spores).

REFERENCES

Tager, A. A. Fizikokhimiia polimerov. 2nd ed. Moscow, 1968. Page 314.
Voiutskii, S. S. Kurs kolloidnoi khimii. Moscow, 1964. Page 482.

L. A. SHITS

swelling

The volume increase caused by wetting, absorption of moisture, or chemical changes.
References in periodicals archive ?
The tumefaction of the upper arm persisted, and a biopsy was performed.
Eleven weeks after treatment ended, the patient had recovered, and the tumefaction of the arm had disappeared.
A cadaver was observed in the Universidad Industrial de Santander's Morphological Medicine Laboratory (Bucaramanga, Colombia) having a firm nervous ganglion-like tumefaction (1.5 x 0.8 x 0.3 cm) on the right vagus nerve at superior mediastinal level (Fig.
MRI showed well-circumscribed tumefaction within HFP of heterogeneous, predominantly hypodense T1/T2 signal.
L'examen clinique demontrait une tumefaction induree situee sur le raphe median au niveau de l'angle perineoscrotal.
Il faut rappeler la necessite de proceder a des examens complementaires afin de ne pas retarder le diagnostic de cancer de l'uretre chaque fois qu'apparait chez un patient suivi pour retrecissement uretral un evenement inhabituel tel que dilatation hemorragique, apparition d'une tumefaction genitale, aggravation rapide de la dysurie, fistule ou ecoulement uretral purulent.
Instrumentation or surgery of the genitourinary tract may cause an idiosyncratic tumefaction comprising spindle cells, known simply as postoperative spindle cell nodule (132,133) (Figure 16, A and B).
His physical examination showed a left axillary tumefaction 2 inches in diameter.
Tumefaction de la jambe a Neocosmospora vasinfecta chez un transplante renal.
Some areas covered include acquired melanocytic nevi, congenital nevi and tumefactions, blue nevi and variants, combined nevi, pigmented epithelioid melanocytoma, tumorigenic melanomas of WHO classification categories, neutrotropic melanoma, metastastic melanoma, and nonmelanocytic melanoma simulants.
Kerions (nodular, exudative, circumscribed tumefactions covered with pustules) usually respond to systemic antifungal therapy.