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.

Q: The objective in lung transplantation is to prolong life, but the survival effect in patients with chronic obstructive pulmonary disease (COPD) or alpha1-anti-trypsin deficiency emphysema is still unresolved. This study assesses the impact of diagnosis, single-lung transplantation (SLT) vs bilateral lung transplantation (BLT) and timing of transplantation on survival in a national cohort.', 'In 219 consecutive patients accepted onto the lung transplantation waiting list in Norway, 1990 to 2003, we assessed predictors of death: (1) on the waiting list; (2) <or=90 days after transplantation; and (3) >90 days after transplantation. For each period we used Cox regression, including age, gender, diagnosis, baseline pulmonary function tests, cardiac catheterization data, exercise capacity and transplant type, as potential predictors. Survival benefit was assessed graphically by combining adjusted survival curves after transplantation with the curve for those waiting, modeling transplantation after 6, 12 or 24 months.', 'Mean patient age was 49 years (SD 10), with 55% women. High forced expiratory volume in 1 second (FEV(1)) percentage predicted death on the waiting list. Diagnoses other than COPD/emphysema and receiving SLT were associated with death <or=90 days after transplantation. Only low forced vital capacity (FVC) percentage predicted death >90 days after transplantation. In COPD/emphysema, there was no clear survival benefit from BLT or SLT. For patients in the "Other" group, the data suggest a survival benefit from BLT.

A: Is lung transplantation in patients with chronic obstructive pulmonary disease in a national cohort without obvious survival benefit?
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Q: Obese persons have low circulating natriuretic peptide (NP) concentrations. It has been proposed that this 'natriuretic handicap' could play a role in obesity-related hypertension. The normal physiological response of the NP system to an increase in blood pressure (BP) is an increase in NP secretion with concomitant higher circulating NP concentrations. In this study, we investigated whether higher BP would also be related to higher circulating NP concentrations in obese men; furthermore, we verified that BP had affected the hearts of our study participants, by determining left ventricular mass (LVM).", 'We examined 103 obese healthy medication-free men. We measured 24-hour ambulatory BP (ABP). LVM was calculated using the Cornell voltage-duration product method. Fasting serum concentrations of midregional proatrial NP (MR-proANP), a surrogate for active ANP, were measured. Linear regression analysis was used to calculate age-adjusted standardised regression coefficients ().', 'LVM and BP increased across systolic ABP quartiles (mean LVMSD: 1599.1387.2mmms in first vs 2188.5551.3mmms in fourth quartile, p<0.001; mean systolic ABPSD: 114.54.2mmHg in first vs 149.07.7mmHg in fourth quartile, p<0.001). Systolic ABP was robustly associated with LVM (=0.48, p<0.001). Despite evidence of BP-related increases in LVM, serum MR-proANP was negatively associated with systolic ABP (=-0.32, p=0.004) and with diastolic ABP (=-0.45, p<0.001).

A: Does serum proatrial natriuretic peptide increase with higher systolic blood pressure in obese men?
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Q: Microsporogenesis in monocots is often characterized by successive cytokinesis with centrifugal cell plate formation. Pollen grains in monocots are predominantly monosulcate, but variation occurs, including the lack of apertures. The aperture pattern can be determined by microsporogenesis features such as the tetrad shape and the last sites of callose deposition among the microspores. Potamogeton belongs to the early divergent Potamogetonaceae and possesses inaperturate pollen, a type of pollen for which it has been suggested that there is a release of the constraint on tetrad shape. This study aimed to investigate the microsporogenesis and the ultrastructure of pollen wall in species of Potamogeton in order to better understand the relationship between microsporogenesis features and the inaperturate condition.', 'The microsporogenesis was investigated using both light and epifluorescence microscopy. The ultrastructure of the pollen grain was studied using transmission electron microscopy.', 'The cytokinesis is successive and formation of the intersporal callose wall is achieved by centrifugal cell plates, as a one-step process. The microspore tetrads were tetragonal, decussate, T-shaped and linear, except in P. pusillus, which showed less variation. This species also showed a callose ring in the microsporocyte, and some rhomboidal tetrads. In the mature pollen, the thickening observed in a broad area of the intine was here interpreted as an artefact.

A:
Is release of developmental constraints on tetrad shape confirmed in inaperturate pollen of Potamogeton?
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