In this paper, a multiscale approach spanning atomistic and mesoscopic regimes to model the rheology of suspensions that have strongly interacting particles in highly viscous solvents is presented. ...The model suspensions studied here have 65% sucrose solution-a Newtonian fluid with a viscosity of 170 cP at room temperature-as the solvent phase with ceramic particles of sizes on the order of a few microms as the dispersed (solute) phase. A multiscale approach is proposed to quantitatively account for the effect of the properties of constituent materials on the bulk rheology of the suspension apart from the effect of hydrodynamic factors. A dissipative particle dynamics-type particle-based approach is adopted to which material-specific, mesoscopic force fields developed using molecular dynamics are fed. Issues pertaining to the handling of the vast spectrum of time and length scales present and an appropriate Gallilean-invariant thermostat for solvent dynamics are addressed and resolved. Numerical calculations compare reasonably well to experimentally measured viscosities up to reasonably high Peclet numbers (approximately 10(4)).
The patient with gastric ulcer (GU) has abnormal reflux of bile-containing duodenal contents into the stomach. Antral gastritis is prominently associated with GU and is more extensive with severe ...reflux and with ulcer chronicity and probably when bile salts are accompanied by other constituents of duodenal fluids. Smoking is significantly associated with GU, and it produces reflux in normal subjects and in patients with duodenal ulcer, which in turn is commonly associated with GU. Reflux has not been shown to precede either the gastritis or the gastric ulcer and probably persists despite ulcer healing. The pyloric spincter in the patient with GU probably contracts subnormally to endogenous or exogenous secretin or CCK. This can be explained by associated hypergastrinemia since antral acidification improves the response. Because the pylorus may be usually open, abnormal reflux may be related as much or more to disturbances of other gastroduodenal functions known to control the movement of chyme through what may be a relatively passive pyloric zone. Speculation from animal models implicates bile reflux in aspirin-induced and shock-related gastric ulceration and assigns to bile a possible explanation, in part at least, for the apparent therapeutic efficacy of a carbenoxalone derivative and an antipepsin agent. Similar speculation warrants a search in the patient with GU for abnormalities of gastroduodenal peristalsis-related electric activity and for impaired release of secretin, possibly from antral cells of production. Possible abnormal purinergic inhibition of the gastric fundus and pylorus also warrants further study.
Dermatological manifestations of chronic infammatory bowel disease are numerous. We report herein 2 cases that demonstrated the uncommon association of cutaneous polyarteritis nodosa with regional ...enterocolitis. The clinical and histopathological features of this skin disease are important. Particular emphasis is placed on its relative benignity, in contrast to the serious prognosis associated with systemic polyarteritis nodosa.
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