Given a passage with a context and an answer, 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.

Context: Rapa Nui (Easter Island), located in the easternmost corner of the Polynesian Triangle, is one of the most isolated locations on the planet inhabited by humans. Archaeological and genetic evidence suggests that the island was first colonized by Polynesians around AD 1200, during their eastward expansion. Although it remains contentious whether Polynesians reached South America, suggestive evidence has been brought forward supporting the possibility of Native American contact prior to the European "discovery" of the island in AD 1722.', 'We generated genome-wide data for 27 Rapanui. We found a mostly Polynesian ancestry among Rapanui and detected genome-wide patterns consistent with Native American and European admixture. By considering the distribution of local ancestry tracts of eight unrelated Rapanui, we found statistical support for Native American admixture dating to AD 1280-1495 and European admixture dating to AD 1850-1895.
Answer: These genetic results can be explained by one or more pre-European trans-Pacific contacts.
Do genome-wide ancestry patterns in Rapanui suggest pre-European admixture with Native Americans?

Context: Activation of NF-kappaB signaling pathway plays a critical role in the initiation and progression of carcinogenesis. However, the role of NF-kappaB pathway in esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. Studies have shown that curcumin possesses anti-infection and anti-oxidation effects. This study was to evaluate whether curcumin could induce apoptosis through inhibition of NF-kappaB signaling pathway in ESCC cells.', 'Expressions of pIkappaBalpha and Bcl-2 were detected using Western blott after incubation of ESCC cells with curcumin (50 micromol/L) at different time points. Apoptosis and the number of viable ESCC cells were analyzed using flow cytometry and MTT, respectively, after the treatment of curcumin, 5-FU, or the combination of curcumin and 5-FU.', 'In two ESCC cell lines, EC9706 and Eca109,curcumin inhibited IkappaBalpha phosphorylation and Bcl-2 in a time-dependent manner; curcumin alone increased cell apoptosis (P<0.05), and the effect became more prominent when it was combined with 5-FU (P<0.05); curcumin plus 5-FU exerted a stronger inhibition effect on cell proliferation than curcumin alone (P<0.05) or 5-FU alone (P<0.05).
Answer: Curcumin inhibits the phosphorylation of IkappaBalpha, leading to suppression of proliferation, induction of apoptosis and an increase of the sensitivity of ESCC cell lines towards 5-FU.
Does [ Curcumin promote apoptosis of esophageal squamous carcinoma cell lines through inhibition of NF-kappaB signaling pathway ]?

Context: Chitosan has been shown to be a non-toxic and efficient vector for in vitro gene transfection and in vivo gene delivery through pulmonary and oral administrations. Recently, we have shown that chitosan/DNA nanoparticles could mediate high levels of gene expression following intrabiliary infusion 1. In this study, we have examined the possibility of using polyethylene glycol (PEG)-grafted chitosan/DNA complexes to deliver genes to the liver through bile duct and portal vein infusions.', 'PEG (Mw: 5 kDa) was grafted onto chitosan (Mw: 47 kDa, deacetylation degree: 94%) with grafting degrees of 3.6% and 9.6% (molar percentage of chitosan monosaccharide units grafted with PEG). The stability of chitosan-g-PEG/DNA complexes was studied by measuring the change in particle size and by agarose gel electrophoresis against bile or serum challenge. The influence of PEG grafting on gene transfection efficiency was evaluated in HepG2 cells using luciferase reporter gene. Chitosan and chitosan-g-PEG/DNA complexes were delivered to the liver through bile duct and portal vein infusions with a syringe pump. Gene expression in the liver and the distribution of gene expression in other organs were evaluated. The acute liver toxicity of chitosan and chitosan-g-PEG/DNA complexes was examined by measuring serum alanine aminotranferase (ALT) and aspartate aminotransferase (AST) activities as a function of time.', 'Both chitosan and chitosan-g-PEG displayed comparable gene transfection efficiency in HepG2 cells. After challenge with serum and bile, chitosan-g-PEG/DNA complexes, especially those prepared with chitosan-g-PEG (GD = 9.6%), did not form large aggregates like chitosan/DNA complexes but remained stable for up to 30 min. In addition, chitosan-g-PEG prevented the degradation of DNA in the presence of serum and bile. On day 3 after bile duct infusion, chitosan-g-PEG (GD = 9.6%)/DNA complexes mediated three times higher gene expression in the liver than chitosan/DNA complexes and yielded background levels of gene expression in other organs. On day 1 following portal vein infusion, gene expression level induced by chitosan/DNA complexes was hardly detectable but chitosan-g-PEG (GD = 9.6%) mediated significant transgene expression. Interestingly, transgene expression by chitosan-g-PEG/DNA complexes in other organs after portal vein infusion increased with increasing grafting degree of PEG. The ALT and AST assays indicated that grafting of PEG to chitosan reduced the acute liver toxicity towards the complexes.
Answer: This study demonstrated the potential of chitosan-g-PEG as a safe and more stable gene carrier to the liver.

Do chitosan-g-PEG/DNA complexes deliver gene to the rat liver via intrabiliary and intraportal infusions?