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.

[EX Q]: To fully understand the cytotoxicity of after-degradation QDs, we synthesized CdS QDs and investigated its toxicity mechanism.', 'Biomimetic method was proposed to synthesize cadmium sulfide (CdS) QDs. Thereafter MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay was conducted to evaluate their cytotoxicity. To investigate the toxicity mechanism, we subsequently conducted intracellular reactive oxygen species (ROS) measurement with DCFH-DA, glutathione (GSH) measurement with DTNB, and cellular cadmium assay using atomic absorption spectrometer. Microsized CdS were simultaneously tested as a comparison.', "MTT assay results indicated that CdS QDs are more toxic than microsized CdS especially at concentrations below 40 microg/ml. While microsized CdS did not trigger ROS elevation, CdS QDs increase ROS by 20-30% over control levels. However, they both deplete cellular GSH significantly at the medium concentration of 20 microg/ml. In the presence of NAC, cells are partially protected from CdS QDs, but not from microsized particles. Additionally, nearly 20% of cadmium was released from CdS nanoparticles within 24h, which also accounts for QDs' toxicity.
[EX A]: Do intracellular oxidative stress and cadmium ions release induce cytotoxicity of unmodified cadmium sulfide quantum dots?

[EX Q]: Hypoxemia is a common complication of chronic obstructive pulmonary disease and a major factor in patients' prognosis and quality of life. The response to exercise has been evaluated by various means but no standardization has been accepted.", 'To suggest a simple outpatient technique for evaluating the response of arterial oxygen saturation to exercise for use as a marker of disease severity.', 'Ninety-six patients with various degrees of COPD were divided into three groups: mild (forced expiratory volume in 1 sec > 65%), moderate (FEV1 between 50 and 65%), and severe (FEV1 < 50%). Using continuous oximeter recording we measured oxygen saturation during 15 steps of climbing, and quantified oxygen desaturation by measuring the "desaturation area," defined as the area under the curve of oxygen saturation from the beginning of exercise through the lowest desaturation point and until after recovery to the baseline level of oxygen percent saturation. Desaturation was correlated to spirometry, lung gas volumes, blood gas analysis, and 6 min walking distance.', 'A good correlation was found between severity of COPD and baseline SaO2, lowest SaO2, recovery time, and desaturation area. A negative correlation was found between desaturation area and FEV1 (r = -0.65), FEV1/forced vital capacity (r = -0.58), residual volume to total lung capacity (r = 0.52), and diffusing lung capacity for carbon monoxide (r = -0.52). In stepwise multiple regression analysis only FEV1 correlated significantly to desaturation area. A good correlation was noted between 6 min walking distance and desaturation area with the 15 steps technique (r = 0.56).
[EX A]: Do quantitative 15 steps exercise oximetry as a marker of disease severity in patients with chronic obstructive pulmonary disease?

[EX Q]: The receptor activator of NF-kB ligand (RANKL) has a critical role in osteoclast activation. Recently it has been demonstrated that human multiple myeloma (MM) cells do not express RANKL but up-regulate RANKL in bone marrow stromal cells (BMSC). To further investigate the role of RANKL in the pathophysiology of MM we evaluated the expression of its receptor RANK in MM cells and in the BM environment and the potential role of RANKL in the interaction of myeloma cells with the microenvironment.', 'RANK mRNA and protein expression were evaluated by reverse transcription polymerase chain reaction and Western blot analysis in human myeloma cell lines (HMCL), fresh purified MM cells, BMSC and endothelial cells. Moreover the effect and the role of RANKL on cytokine secretion were evaluated in BMSC, in endothelial cells and in co-culture conditions with myeloma cells.', 'We found that RANK is expressed in BMSC and endothelial cells but not in myeloma cells. Consistently, RANKL did not have a direct effect on myeloma cell survival, but RANKL treatment induced a significant increase of interleukin (IL)-6 and IL-11 secretion by both BMSC and endothelial cells. Moreover, in a co-culture system we found that myeloma cells up-regulated both IL-6 and IL-11 secretion by BMSC and endothelial cells through cell-to-cell contact. The presence of the RANK-Fc that blocks the RANK/RANKL interaction significantly inhibited HMCL-induced secretion of IL-6 and IL-11.
[EX A]:
Is the RANK/RANK ligand system involved in interleukin-6 and interleukin-11 up-regulation by human myeloma cells in the bone marrow microenvironment?