Given a passage with a context and an answer, 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]: Context: The shape of the ionizing radiation response curve at very low doses has been the subject of considerable debate. Linear-no-threshold (LNT) models are widely used to estimate risks associated with low-dose exposures. However, the low-dose hyperradiosensitivity (HRS) phenomenon, in which cells are especially sensitive at low doses but then show increased radioresistance at higher doses, provides evidence of nonlinearity in the low-dose region. HRS is more prominent in the G2 phase of the cell cycle than in the G0/G1 or S phases. Here we provide the first cytogenetic mechanistic evidence of low-dose HRS in human peripheral blood lymphocytes using structural chromosomal aberrations.', 'Human peripheral blood lymphocytes from 2 normal healthy female donors were acutely exposed to cobalt 60 γ rays in either G0 or G2 using closely spaced doses ranging from 0 to 1.5 Gy. Structural chromosomal aberrations were enumerated, and the slopes of the regression lines at low doses (0-0.4 Gy) were compared with doses of 0.5 Gy and above.', 'HRS was clearly evident in both donors for cells irradiated in G2. No HRS was observed in cells irradiated in G0. The radiation effect per unit dose was 2.5- to 3.5-fold higher for doses ≤0.4 Gy than for doses >0.5 Gy.
Answer: These data provide the first cytogenetic evidence for the existence of HRS in human cells irradiated in G2 and suggest that LNT models may not always be optimal for making radiation risk assessments at low doses.
[EX A]: Is cytogenetic low-dose hyperradiosensitivity observed in human peripheral blood lymphocytes?

[EX Q]: Context: Breast reconstruction (BR) following mastectomy for breast cancer has been shown to improve quality of life and body image; however, there is significant geographic variation in BR rates. We explored factors associated with BR following mastectomy.', 'This is a population-based data linkage study consisting of cancer registry records linked to hospital inpatient episodes for 4104 women aged 20\u2009years and over-diagnosed with a first primary invasive localized stage breast cancer between 1997 and 2012 in Queensland, Australia, who underwent a mastectomy. Multivariate logistic regression was used to model predictors of BR.', 'Overall, 481 women (11.7%) underwent reconstruction. Proportions increased over time and were higher for younger women. Younger age, more recent diagnosis, living in high or very high accessibility areas or less disadvantaged areas, smaller tumours and attending a private or high-volume hospital independently increased the odds of reconstruction. The geographical disparity reduced significantly over time.
Answer: Geographical barriers to accessing BR have reduced; however, continued monitoring and further research to inform strategies to further reduce subgroup disparities remain a priority.
[EX A]: Does geographical disparity in breast reconstruction following mastectomy have reduced over time?

[EX Q]: Context: The contribution of neutrophils to myocardial injury during stunning remains controversial because of conflicting results in neutropenic animals. The goal of this study was to compare the recovery of function in stunned myocardium using two distinct methods for inducing neutropenia in pigs.', 'Three groups of pigs were studied: control (n = 6), and made neutropenic by either Leukopak blood filters (n = 7), or cyclophosphamide (n = 7, 50 mg.kg-1 intravenously 4 d prior to study). In anaesthetised open chest pigs, with the heart paced at 110 beats.min-1, the left anterior descending coronary artery was perfused with an extracorporeal circuit at controlled coronary pressure (CP) and the regional coronary blood flow was measured. Systolic wall thickening was determined by sonomicrometry in the left anterior descending and circumflex coronary artery regions. The protocol consisted of 15 min of low flow ischaemia (CP = 40 mm Hg), followed by a staged reperfusion over 10 min back to baseline (CP = 90 mm Hg), and continued for 2 h. Blood filtration was initiated prior to ischaemia and stopped after 90 min reperfusion.', 'In both treated groups during ischaemia and the initial 60 min of reperfusion the neutrophil count was severely depleted to < 5% compared to the control group. Aortic pressure, coronary blood flow during ischaemia, area at risk, and systolic wall thickening in the circumflex region were similar between groups. Recovery of systolic wall thickening in the left anterior descending region after reperfusion was equivalent in all three groups. In the filter group, arrhythmias during ischaemia and reperfusion were significantly less.
Answer: As assessed in the pig model of myocardial stunning and using two different methods, severe neutropenia does not reduce the depression of contractile function.
[EX A]:
Does severe neutrophil depletion by leucocyte filters or cytotoxic drug improve recovery of contractile function in stunned porcine myocardium?