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]: To examine the expression of Twist1 in cervical cancer and to explore its biological function in the progression of cervical cancer.\u2029', 'The expressions of Twist1 in 32 cervical cancers and matched normal tissues were examined by immunohistochemistry (IHC). Cell invasive ability and the expression of invasion-related genes were determined in RNAi-based Twist1-silencing HeLa cells. The relationship between Twist1 and microRNA-33a (miR-33a) in cervical cancer was studied by Pearson correlation analysis, and the roles of miR-33a in regulation of Twist1 and cell invasiveness were studied.\u2029', 'The positive expression rate of Twist1 was 75.0% (24/32) and 21.9% (7/32) in the cervical cancer and the matched normal tissues, respectively, with significant difference between them (P<0.05). Twist1 shRNA significantly decreased the invasiveness of HeLa cells (P<0.05). Compared with the matched normal tissues, the expression of miR-33a was increased in the cervical cancer tissues, which was negatively correlated with Twist1 (r=-0.661, P<0.05). Overexpression of miR-33a could significantly suppress Twist1 expression as well as cell invasiveness (P<0.05).\u2029
[EX A]: Does [ MicroRNA-33a regulate the invasion of cervical cancer cells via targeting Twist1 ]?

[EX Q]: The EuroSCORE (European System for cardiac operative risk evaluation) stratifies cardiac risk surgery in easy and accessible manner; it was validated in North America with good results but in many countries of Latin America is used routinely without prior validation. Our objective was to validate the EuroSCORE in patients with cardiac valve surgery at the Instituto Nacional de Cardiología Ignacio Chávez (INCICh) in México.', 'EuroSCORE additive and logistic models were used to predict mortality in adults undergoing cardiac valve surgery from march 2004 to march 2008. The goodness of fit test of Hosmer-Lemeshow was used to evaluate the calibration. The area under the ROC curve was calculated to determinate discrimination.', 'We included 1188 patients with ages of 51.3±14.5 years, 52% women. There were significant differences in the prevalence of risk factors among the INCICh and the EuroSCORE populations. Total mortality was 9.68% versus 5% and 5.6% predicted by additive and logistic EuroSCORE. According to additive EuroSCORE the risk was low in 11.3%, intermediate in 52.9% and high in 35.9%; for these groups the mortality was .7%, 6.34% and 17.4% against those predicted of 2%, 3.9% and 7.64%. Hosmer-Lemeshow test had a P<.001 for both models and the area under the ROC curve was .707 and .694 for additive and logistic EuroSCORE.
[EX A]: Do [ EuroSCORE underestimate the mortality risk in cardiac valve surgery of Mexican population ]?

[EX Q]: Accumulating evidence from observational studies indicates that a high calcium intake may reduce body weight and body fat. However, few randomized trials have been conducted.', 'We examined whether calcium supplementation affects body weight and body fat in young girls and whether a relation exists between habitual calcium intake and body weight and body fat.', 'A randomized, double-blind, placebo-controlled intervention study was conducted in 110 young girls. The subjects were randomly assigned to receive 500 mg Ca/d as calcium carbonate or placebo for 1 y. Two groups of girls were selected according to habitual calcium intake from a large group; one group consumed 1000-1304 mg/d (40th-60th percentile; n = 60) and the other group consumed <713 mg/d (<20th percentile; n = 50). Height, body weight, body fat, and calcium intake were measured at baseline and after 1 y.', 'At baseline a significant negative correlation was observed between habitual dietary calcium intake and percentage of body fat (r = -0.242, P = 0.011). However, calcium supplementation had no effect on height, body weight, or percentage body fat.
[EX A]:
Does calcium supplementation for 1 y reduce body weight or fat mass in young girls?