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: To examine the direct effect of high glucose levels on primary cultured human retinal capillary endothelial cells (HRCEC).', 'HRCECs were isolated from donated eyes and cultured for 6 days in the media containing 5 or 25 mmol/L glucose. The cell viability was determined by trypan blue exclusion assay and cell cycle analyzed by flow cytometry, with the cell apoptosis assayed by TUNEL method.', 'The cell viability was significantly decreased after exposure to 25 mmol/L glucose, and the number of apoptotic cells determined by flow cytometry and TUNEL was significantly increased in response to high-dose glucose treatment.

A: Does [ High-dose glucose induce human retinal endothelial cell apoptosis ]?
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Q: To investigate the influences of bicortical anchorage on values of natural frequencies of dental implants utilizing the 3-dimensional finite element analysis.', 'Using the commercial code of Solidworks, 3-D models of a screw-shaped dental implant and a mandibular bone segment were generated. After the 3-D implant-bone complex was meshed by ABAQUS software, effects of bicortical anchorage on the buccolingual and axial first-order natural frequencies of the implant were computed.', 'Bicortical anchorage increased both the buccolingual and axial natural frequencies remarkably. As the bicortical anchorage got deeper, the frequencies correspondingly got higher.

A: Do [ Influence of bicortical anchorage on the natural frequencies of dental implant ]?
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Q: Resting heart rate (RHR) declines with exercise training. Possible mechanisms include: 1) increased parasympathetic tone, 2) decreased responsiveness to beta-adrenergic stimulation, 3) decreased intrinsic heart rate or 4) combination of these factors.', 'To determine whether an increase in resting parasympathetic tone or decrease in response to beta-adrenergic stimulation contributes to the decrease in RHR with training.', '51 screened healthy subjects aged 18-32 (n=20, mean age 26, 11 female) or 65-80 (n=31, mean age 69, 16 female) were tested before and after 6months of supervised exercise training. Heart rate response to parasympathetic withdrawal was assessed using atropine and beta-adrenergic responsiveness during parasympathetic withdrawal using isoproterenol.', 'Training increased VO2 max by 17% (28.7±7.7 to 33.6±9.20ml/kg/min, P<0.001). RHR decreased from 62.8±6.6 to 57.6±7.2 beats per minute (P<0.0001). The increase in heart rate in response to parasympathetic withdrawal was unchanged after training (+37.3±12.8 pre vs. +36.4±12.2 beats per min post, P=0.41). There was no change in the heart rate response to isoproterenol after parasympathetic blockade with training (+31.9±10.9 pre vs. +31.0±12.0 post beats per min, P=0.56). The findings were similar in all four subgroups.

A:
Is exercise training bradycardia largely explained by reduced intrinsic heart rate?
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