Swelling drops

The tria2ine family of herbicides appeared in and after 1955, and the bipyridiniums in 1960. In 1967, two new chemical herbicides (1) were registered under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The number of new registrations swelled to 11 in 1975 and subsequendy dropped to three in 1990 and two in 1991. 

Metabolic acidosis can also result when a person is severely burned. Blood plasma leaks from the circulatory system into the injured area, producing edema (swelling) and reducing the blood volume. If the burned area is large, this loss of blood volume may be sufficient to reduce blood flow and oxygen supply to all the body s tissues. Lack of oxygen, in turn, causes the tissues to produce an excessive amount of lactic acid and leads to metabolic acidosis. To minimize the decrease in pH, the injured person breathes harder to eliminate the excess C02. However, if blood volume drops below levels for which the body can compensate, a vicious circle ensues in which blood flow decreases still further, blood pressure falls, C02 excretion diminishes, and acidosis becomes more severe. People in this state are said to be in shock and will die if not treated promptly. 

The a used here corresponds to the isotropic swelling factor for the cross-linked gels treated in Chapter XIII. The subscript is dropped for simplicity. 

When a bead of a gel-type CFP material is in the dry state, for practical purposes it can be considered as a solid material (thus possessing a mass, a volume and a shape). When in the swollen state, a CFP material can be still considered as a solid from the practical point of view, but this circumstance is now an authentic approximation. In fact, physico-chemical analysis reveals that under some circumstances this alleged solid material is rather a very viscous liquid. More precisely, it is a suspension of interconnected polymer chains in the swelling agent. Each swollen CFP bead can be considered as a drop, which can retain a definite shape owing to the existence of the polymer framework. 

Pure PHEMA gel is sufficiently physically cross-linked by entanglements that it swells in water without dissolving, even without covalent cross-links. Its water sorption kinetics are Fickian over a broad temperature range. As the temperature increases, the diffusion coefficient of the sorption process rises from a value of 3.2 X 10 8 cm2/s at 4°C to 5.6 x 10 7 cm2/s at 88°C according to an Arrhenius rate law with an activation energy of 6.1 kcal/mol. At 5°C, the sample becomes completely rubbery at 60% of the equilibrium solvent uptake (q = 1.67). This transition drops steadily as Tg is approached ( 90°C), so that at 88°C the sample becomes entirely rubbery with less than 30% of the equilibrium uptake (q = 1.51) (data cited here are from Ref. 138). 

Anaphylaxis is a severe systemic allergic reaction, which can be fatal. Frequently the first symptom is itchy hives (welts) within minutes of exposure. Swelling of the larynx, with constriction of the air passage and a rapid drop in blood pressure quickly follow. Treatment includes immediate removal from exposure, administration of epinephrine, and strict avoidance of reexposure. 

Symptoms Dark brown/green blotches develop on the leaves these may expand along the veins and run into each other. Leaves may drop prematurely. Dark spots, which develop into corky patches, appear on the fruit skin. Fruit may crack, but does not rot In severe cases, twigs blister, swell, and burst to produce brown-green pustules in spring. 

The amphiphilic brush displayed dynamic wetting behavior towards selective solvents such as water. If the substrate was immersed in water and then air-dried, an initial contact angle (sessile drop) of 80-75° was found, because of selective swelling... 

The mechanism of formation of jets such as that in Fig. 6 is not clear but apparently is associated with swelling of the La or L3 phase (the latter can also exist at very low surfactant concentrations, as shown in Fig. 1). The phenomenon resembles the tip streaming observed in drops of liquids subjected to shear or extensional flows with surfactants present [12,13]. In these cases shear stresses from the flow in the external phase cause the drop to elongate and form a jet with a conical shape similar to that seen in Fig. 6. No such external flow is present here, but perhaps flow inside the drop accompanying the swelling process produces a similar effect. 

Owens and Punte3 tested CS solutions in rabbits and monkeys by dropping 0.2 ml of 1% CS in dipropylene glycol into one eye of each rabbit or monkey, the other eye serving as a control. Six animals were used in each test. Conjunctival redness and swelling lasted for 1-3 d. The experiment was repeated, but with applications of 0.2 and 0.05 ml on 5 successive days. The 0.2-ml applications produced conjunctivitis, iritis, severe chemosis, and corneal ulceration. The 0.05-ml applications resulted in conjunctivitis, moderate chemosis, and iritis. These conditions had all cleared 7-10 d after the last dose. Rabbits and monkeys had qualitatively similar symptoms, but they were less severe in the monkeys. 

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