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]: Fetal hypoxia is an important determinant of neonatal encephalopathy caused by birth asphyxia, in which hypoxia-induced free radical formation plays an important role.', 'Maternal treatment with allopurinol, will cross the placenta during fetal hypoxia (primary outcome) and reduce S-100B and free radical formation (secondary outcome).', 'In a randomized, double-blind feasibility study, 53 pregnant women in labor (54 fetuses) with a gestational age of >36 weeks and fetal hypoxia, as indicated by abnormal/nonreassuring fetal heart rate tracing or fetal scalp pH of <7.20, received 500 mg of allopurinol or placebo intravenously. Severity of fetal hypoxia, brain damage and free radical formation were assessed by arterial cord blood lactate, S-100B and non-protein-bound-iron concentrations, respectively. At birth, maternal and cord blood concentrations of allopurinol and its active metabolite oxypurinol were determined.', 'Allopurinol and oxypurinol concentrations were within the therapeutic range in the mother (allopurinol > 2 mg/L and/or oxypurinol > 4 mg/L) but not always in arterial cord blood. We therefore created 3 groups: a placebo (n = 27), therapeutic allopurinol (n = 15), and subtherapeutic allopurinol group (n = 12). Cord lactate concentration did not differ, but S-100B was significantly lower in the therapeutic allopurinol group compared with the placebo and subtherapeutic allopurinol groups (P < .01). Fewer therapeutic allopurinol cord samples had measurable non-protein-bound iron concentrations compared with placebo (P < .01).
[EX A]: Does maternal allopurinol during fetal hypoxia lower cord blood levels of the brain injury marker S-100B?

[EX Q]: The current American Joint Committee on Cancer Seventh Edition (AJCC7) pathologic staging for esophageal adenocarcinoma (EAC) is derived from data assessing the outcomes of patients having undergone esophagectomy without neoadjuvant treatment and has unclear significance in patients who have received multimodality therapy. Lymph nodes with evidence of neoadjuvant treatment effect without residual cancer cells may be observed and are not traditionally considered in pathologic reports, but may have prognostic significance.', 'All patients who underwent esophagectomy after completing neoadjuvant therapy for EAC at our institution between 2006 and 2012 were reviewed. Slides of pathologic specimens were reexamined for locoregional treatment-response nodes lacking viable cancer cells but with evidence of acellular mucin pools, central fibrosis, necrosis, or calcifications suggesting prior tumor involvement. Kaplan-Meier survival functions were estimated, and Cox proportional hazards regression models were used to compare staging models.', 'Ninety patients (82 men) underwent esophagectomy after neoadjuvant therapy for EAC (mean age, 61.8 ± 8.9 years). All patients received preoperative chemotherapy, and 50 patients also underwent preoperative radiotherapy. Median Kaplan-Meier survival was 55.6 months, and 5-year survival was 35% (95% confidence interval, 19% to 62%). A total of 100 treatment-response nodes were found in 38 patients. For patients with limited nodal disease (62 ypN0-N1), the presence of treatment-response nodes was associated with significantly worse survival (p = 0.03) compared with patients lacking such nodes. Adjusting for patient age and AJCC7 pathologic stage showed the presence of treatment-response nodes significantly increased the risk of death (hazard ratio, 2.7; 95% confidence interval, 1.1 to 6.9; p = 0.04). When stage-adjusted survival was modeled, counting treatment-response nodes as positive nodes offered a better model fit than ignoring them.
[EX A]: Is neoadjuvant treatment response in negative nodes an important prognosticator after esophagectomy?

[EX Q]: Caenorhabditis elegans chemosensation has been successfully studied using behavioral assays that treat detection of volatile and water soluble chemicals as separate senses, analogous to smell and taste. However, considerable ambiguity has been associated with the attractive properties of the compound ammonium-acetate (NH(4)Ac). NH(4)Ac has been used in behavioral assays both as a chemosensory neutral compound and as an attractant.', 'Here we show that over a range of concentrations NH(4)Ac can be detected both as a water soluble attractant and as an odorant, and that ammonia and acetic acid individually act as olfactory attractants. We use genetic analysis to show that NaCl and NH(4)Ac sensation are mediated by separate pathways and that ammonium sensation depends on the cyclic nucleotide gated ion channel TAX-2/TAX-4, but acetate sensation does not. Furthermore we show that sodium-acetate (NaAc) and ammonium-chloride (NH(4)Cl) are not detected as Na(+) and Cl(-) specific stimuli, respectively.
[EX A]:
Is ammonium-acetate sensed by gustatory and olfactory neurons in Caenorhabditis elegans?