instruction:
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.
question:
In this study, we examined chondrogenic regulation of 2 types of mesenchymal stem cells seeded on the bioengineered substrate in monolayer cultures under mechanically defined conditions to mimic the in vivo microenvironment of chondrocytes within articular cartilage tissues.', 'Human adipose-derived mesenchymal stem cells (ASCs) and bone marrow mesenchymal stem cells (BSCs) were exposed to 0.2 Pa shear stress, 3 MPa cyclic hydrostatic pressure, and combined loading with different sequences on chemically designed medical-grade silicone rubber, while no soluble growth factors were added to the culture medium. The expression levels of chondrogenic-specific genes of SOX9, aggrecan, and type II collagen (Col II) were measured. Results were compared to those of cells treated by biological growth factor.', 'Gene expression patterns were dependent on the loading regime. Moreover, the source of mesenchymal stem cells (adipose or bone marrow) was influential in gene expression. Overall, enhanced expression of chondrogenic markers was found through application of mechanical stimuli. The response was generally found to be significantly promoted when the 2 loading regimes were superimposed.
answer:
Do the synergistic effects of shear stress and cyclic hydrostatic pressure modulate chondrogenic induction of human mesenchymal stem cells?


question:
To determine whether obese patients undergoing laparoscopic surgery within an enhanced recovery program had worse short-term outcomes.', 'A prospective study of consecutive patients undergoing laparoscopic colorectal resection was carried out between 2008 and 2011 in a single institution. Patients were divided in groups based on body mass index (BMI). Short-term outcomes including operative data, length of stay, complications and readmission rates were recorded and compared between the groups. Continuous data were analysed using t-test or one-way Analysis of Variance. χ(2) test was used to compare categorical data.', 'Two hundred and fifty four patients were included over the study period. The majority of individuals (41.7%) recruited were of a healthy weight (BMI < 25), whilst 50 patients were classified as obese (19.6%). Patients were matched in terms of the presence of co-morbidities and previous abdominal surgery. Obese patients were found to have a statistically significant difference in The American Society of Anesthesiologists grade. Length of surgery and intra-operative blood loss were no different according to BMI.
answer:
Do obese patients have similar short-term outcomes to non-obese in laparoscopic colorectal surgery?


question:
To determine the role of repetitive endocardial focal activations and Purkinje fibers in the maintenance of long duration ventricular fibrillation (LDVF, VF>1 minute) in canine hearts in vivo.', "The study was conducted in electrophysiological laboratory of Shanghai Ruijin hospital from July 2010 to August 2012. A 64-electrode basket was introduced through a carotid artery into the left ventricle (LV) of 11 beagle dogs for global endocardial electrical mapping. In the Lugol's solution group (n=5), the subendocardium was ablated by washing with Lugol's solution. In the control group, (n=6) saline was used for ablation. Before and after saline or Lugol ablation, we determined QRS duration and QT/QTc interval in sinus rhythm (SR). We also measured the activation rates in the first 2 seconds of each minute during 7 minutes of VF for each group. If VF terminated spontaneously in less than 7 minutes, the VF segments used in activation rate analysis were reduced accordingly.", "At the beginning of VF there was no difference between the groups in the activation rate. However, after 1 minute of LDVF the Lugol's solution group had significantly slower activation rate than the control group. In the control group, all episodes of LDVF (6/6) were successfully sustained for 7 minutes, while in the Lugol's solution group 4/5 episodes of LDVF spontaneously terminated before 7 minutes (4.8±1.4 minutes) (P=0.015). In the control group, at 5.1±1.3 minutes of LDVF, a successive, highly organized focal LV endocardial activation pattern was observed. During this period, activations partly arose in PF and spread to the working ventricular myocardium. Mapping analysis showed that these events were consistent with repetitive endocardial focal activations. No evidence of similar focal activations was observed in the Lugol's solution group.
answer:

Does endocardial focal activation originating from Purkinje fibers play a role in the maintenance of long duration ventricular fibrillation?