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]: Retrospective analysis of prospectively collected, nonrandomized radiographical data.', 'To examine the relationship between the presence of preoperative metabolically active facet arthropathy (FA) and the amount of indirect foraminal decompression gained after extreme lateral interbody fusion (XLIF).', 'Although evidence of significant radiographical indirect decompression after XLIF has been shown, the relationship between the extent of indirect decompression and the presence of potentially attenuating, FA is yet to be studied.', 'A prospective database of consecutive patients undergoing XLIF was retrospectively analyzed. Posterior disc height, foraminal height, and cross-sectional foraminal area were measured on computed tomographic scans obtained preoperatively and 2 days postoperatively. The selected radiographical parameters were examined with respect to the presence of FA based on preoperative computed tomographic and bone scans.', 'Fifty-two consecutive patients underwent 79 levels of XLIF without direct decompression. Average age was 66.4 years and 34 (65.4%) were females. Surgery resulted in significant increases in posterior disc height 3.0 to 5.7 mm (89.0% increase), P<0.0001; foraminal height 1.4 to 1.7 cm (38.0% increase), P<0.0001; and foraminal area 1.1 to 1.4 cm (45.1% increase), P<0.0001. These increases were independent of the presence of metabolically active arthropathy.
[EX A]: Is indirect foraminal decompression independent of metabolically active facet arthropathy in extreme lateral interbody fusion?

[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]: As next-generation sequencing (NGS) becomes a major sequencing platform in clinical diagnostic laboratories, it is critical to identify artifacts that constitute baseline noise and may interfere with detection of low-level gene mutations. This is especially critical for applications requiring ultrasensitive detection, such as molecular relapse of solid tumors and early detection of cancer. We recently observed a ~10-fold higher frequency of C:G\xa0>\xa0T:A mutations than the background noise level in both wild-type peripheral blood and formalin-fixed paraffin-embedded samples. We hypothesized that these might represent cytosine deamination events, which have been seen using other platforms.', 'To test this hypothesis, we pretreated samples with uracil N-glycosylase (UNG). Additionally, to test whether some of the cytosine deamination might be a laboratory artifact, we simulated the heat associated with polymerase chain reaction thermocycling by subjecting samples to thermocycling in the absence of polymerase. To test the safety of universal UNG pretreatment, we tested known positive samples treated with UNG.', 'UNG pretreatment significantly reduced the frequencies of these mutations, consistent with a biologic source of cytosine deamination. The simulated thermocycling-heated samples demonstrated significantly increased frequencies of C:G\xa0>\xa0T:A mutations without other baseline base substitutions being affected. Samples with known mutations demonstrated no decrease in our ability to detect these after treatment with UNG.
[EX A]:
Is cytosine deamination a major cause of baseline noise in next-generation sequencing?