Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[EX Q]: Ametop gel (4% amethocaine) is a relatively new topical anesthetic that produces anesthesia within 30 to 45 minutes and therefore may be appropriate for use in busy outpatient settings. The objective of this study was to assess the efficacy and safety of 4% amethocaine in reducing the pain of subcutaneous measles-mumps-rubella vaccination in 1-year-old infants.', 'A double-blind, randomized, placebo-controlled trial was conducted in pediatric outpatient clinics.', 'A total of 120 infants participated in the study; 60 were followed up for assessment of antibody titers after 1 month. Either 1 g of amethocaine or placebo was applied for 30 minutes before vaccination. The Modified Behavioral Pain Scale was used to assess pain; the mean (standard deviation) pain scores for the amethocaine group (n = 61) was 1.5 (1.6) versus 2.3 (2.2) for the placebo group (n = 59). The rate of vaccination success (88% and 87%) was not different between treatment groups.
[EX A]: Does topical 4 % amethocaine gel reduce the pain of subcutaneous measles-mumps-rubella vaccination?

[EX Q]: To determine whether activin A concentrations are altered in chronic fetal hypoxemia and intrauterine fetal growth restriction (IUGR).', 'In vivo animal experimental model.', 'Department of Physiology, Monash University.', 'Chronically catherised fetal sheep in late pregnancy.', 'Chronic fetal hypoxia and IUGR were experimentally induced by single umbilical artery ligation (SUAL) in catheterised fetal sheep. Maternal and fetal blood samples and amniotic fluid (AF) samples were collected during surgery and thereafter on alternate days, until the time of delivery for analyte measurement. Fetal blood gas parameters were measured daily.', 'Plasma and AF was used to analyse activin A, prostaglandin E2 (PGE2) and cortisol and fetal blood gas analysis was undertaken in whole blood.', 'SUAL produced asymmetric IUGR and non-acidaemic chronic fetal hypoxia and resulted in preterm labour (129 [3] days). AF activin A concentrations were 10-fold higher in the SUAL group than in controls whereas levels in the fetal and maternal circulations were similar between groups.
[EX A]: Does chronic fetal hypoxia increase activin A concentrations in the late-pregnant sheep?

[EX Q]: Soluble silica, a ubiquitous component of the diet, may be the natural ligand for dietary aluminum and may prevent its accumulation and toxicity in animals. However, previous studies on the inhibition of aluminum absorption and toxicity by soluble silica have produced conflicting results. We recently identified a soluble silica polymer, oligomeric silica, that has a much higher affinity for aluminum than does monomeric silica and that may be involved in the sequestration of aluminum.', 'By using (26)Al as a tracer, we investigated the effects of oligomeric and monomeric silica on the bioavailability of aluminum (study 1) and compared the availability of silicon from oligomeric and monomeric silica in the human gastrointestinal tract (study 2).', 'In study 1, three healthy volunteers each ingested aluminum alone (control), aluminum with oligomeric silica (17 mg), and aluminum with monomeric silica (17 mg). In study 2, five healthy volunteers ingested both the oligomeric and monomeric forms of silica (34 mg). Serum and urine samples were analyzed for aluminum and silicon.', 'Oligomeric silica reduced the availability of aluminum by 67% (P = 0.01) compared with the control, whereas monomeric silica had no effect (P = 0.40). Monomeric silica was readily taken up from the gastrointestinal tract and then excreted in urine (53%), whereas oligomeric silica was not detectably absorbed or excreted.
[EX A]:
Does oligomeric but not monomeric silica prevent aluminum absorption in humans?