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Query: UMLS:C0344329 (collapse)
 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lactose killing is a peculiar phenomenon in which 80 to 98% of the Escherichia coli cells taken from a lactose-limited chemostat die when plated on standard lactose minimal media. This unique form of suicide is caused by the action of the lactose permease. Since uptake of either lactose or galactose by the lactose permease caused death, the action of rapid transport across the membrane must be the cause of the phenomenon. Alternative causes of lactose killing, such as accumulation of toxic metabolic intermediates or action of the beta-galactosidase, have been eliminated. It is proposed that rapid uptake of sugars by the lactose permease disrupts membrane function, perhaps causing collapse of the membrane potential.
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PMID:Transport by the lactose permease of Escherichia coli as the basis of lactose killing. 9 37

Foam granulation is a relatively newer wet granulation process whereby foamed binder solutions are added to powders in a mixer. It is essential to understand the effect of powder substrate on foam drainage and half-life, which are relevant to nucleation and agglomeration during foam granulation. Hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC) foams were characterized. Anhydrous lactose and stearic acid were selected as model soluble and insoluble substrates, respectively. The effect of these substrates on foam stability was measured by foam drainage and collapse time and microscopic observations. Both HPMC and HPC foams were similar in foam quality and foam density. Lactose destabilized both HPMC and HPC foams and foam drainage and collapse times were reduced two to four times in the presence of lactose. On the contrary, stearic acid did not significantly change foam drainage and collapse times. Microscopically, lactose exhibited rapid wetting within 15 s upon contacting the HPMC and HPC foam beds, whereas stearic acid remained unwetted even after 8 min and collapse of the foam beds. Substrate solubility can influence foam-substrate interaction. On the basis of this, we suggest potential mechanisms of nucleation and agglomeration of soluble and insoluble substrates during foam granulation.
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PMID:Effect of powder substrate on foaml drainage and collapse: implications to foam granulation. 2223 20