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.

This study investigated the isolated and combined effects of heat [temperate (22\xa0°C/30\xa0% rH) vs. hot (35\xa0°C/40\xa0% rH)] and hypoxia [sea level (FiO2 0.21) vs. moderate altitude (FiO2 0.15)] on exercise capacity and neuromuscular fatigue characteristics.', 'Eleven physically active subjects cycled to exhaustion at constant workload (66\xa0% of the power output associated with their maximal oxygen uptake in temperate conditions) in four different environmental conditions [temperate/sea level (control), hot/sea level (hot), temperate/moderate altitude (hypoxia) and hot/moderate altitude (hot\xa0+\xa0hypoxia)]. Torque and electromyography (EMG) responses following electrical stimulation of the tibial nerve (plantar-flexion; soleus) were recorded before and 5\xa0min after exercise.', 'Time to exhaustion was reduced (P\xa0<\xa00.05) in hot (-35\xa0±\xa015\xa0%) or hypoxia (-36\xa0±\xa014\xa0%) compared to control (61\xa0±\xa028\xa0min), while hot\xa0+\xa0hypoxia (-51\xa0±\xa020\xa0%) further compromised exercise capacity (P\xa0<\xa00.05). However, the effect of temperature or altitude on end-exercise core temperature (P\xa0=\xa00.089 and P\xa0=\xa00.070, respectively) and rating of perceived exertion (P\xa0>\xa00.05) did not reach significance. Maximal voluntary contraction torque, voluntary activation (twitch interpolation) and peak twitch torque decreased from pre- to post-exercise (-9\xa0±\xa01, -4\xa0±\xa01 and -6\xa0±\xa01\xa0% all trials compounded, respectively; P\xa0<\xa00.05), with no effect of the temperature or altitude. M-wave amplitude and root mean square activity were reduced (P\xa0<\xa00.05) in hot compared to temperate conditions, while normalized maximal EMG activity did not change. Altitude had no effect on any measured parameters.
Does combining heat stress and moderate hypoxia reduce cycling time to exhaustion without modifying neuromuscular fatigue characteristics?

It has already been demonstrated that the rat esophagus produces retinoic acid from retinol. In this study, this process is further characterized and the effect of acetaldehyde examined to elucidate the possible mechanisms behind the epidemiological evidence that the incidence of esophageal cancer is higher in alcoholics.', 'Rat esophageal samples were incubated with all-trans retinal and newly formed all-trans retinoic acid (ATRA) was quantified using high-performance liquid chromatography (HPLC). Furthermore, beta-nicotinamide adenine dinucleotide (NAD)-dependent acetaldehyde oxidation by the rat esophagus was examined by tracing NAD reduction using a spectrophotometer.', 'Rat esophageal samples produced ATRA from all-trans retinal in a NAD-dependent manner and the potential was significantly attenuated by phenetyl isothiocynate, an ALDH inhibitor, or acetaldehyde depending on the concentration used. Rat esophageal samples also oxidized acetaldehyde of various concentrations NAD dependently. The ATRA formation potential that was temporarily inhibited by acetaldehyde was recovered to the control level by dialysis when the specimen was incubated with up to 50 microM of acetaldehyde.
Does acetaldehyde inhibit the formation of retinoic acid from retinal in the rat esophagus?

Certain aspects of total knee arthroplasty (TKA) in severely and morbidly obese (SMO) patients (BMI ≥ 35 kg/m(2)) remain controversial. This study aimed to assess the duration of TKA surgery and hospital stay in relation to patients' BMI.", 'Three operative times during TKA surgery were recorded: tourniquet time, to determine surgical difficulty, total surgical time, to assess the difficulty of achieving anaesthesia, and time in the surgical area, to assess patient management in the surgical area. Length of hospital stay was also calculated. Data were collected prospectively from consecutive patients and were recorded in a database for retrospective analysis.', 'Data were obtained from 922 consecutive patients undergoing TKA. The non-obese group comprised 418 patients (45.3%), obese group Class I 331 (36%), and the SMO group (Class II-III) 173 (18.7%). Mean tourniquet time was 53 min, mean total surgical time was 84 min, and mean time in the surgical area was 132 min. There were no differences according to BMI group. Median length hospital stay (LHS) was 6 days in all patients regardless of BMI. Factors that significantly prolonged LHS were ASA III-IV and pre-operative haemoglobin between 12 and 13 g/dl.

Does severe and morbid obesity ( BMI ≥ 35 kg/m ( 2 ) ) increase surgical time and length of hospital stay in total knee arthroplasty surgery?