In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

[Q]: BACKGROUND Raised concentrations of nitrate and nitrite have been found in exhaled breath condensate (EBC) in airway disease, and it has been postulated that this reflects increased nitric oxide (NO) metabolism. However, the chemical and anatomical origin of nitrate and nitrite in the airways has not yet been sufficiently studied.
METHODS The fraction of exhaled NO at an exhalation flow rate of 50 ml/s (FE(NO)) and nitrite and nitrate in EBC, nasal condensate, and saliva were measured in 17 tracheostomised and 15 non-tracheostomised subjects, all of whom were non-smokers without respiratory disease. Tracheal and oral samples were taken from the tracheostomised subjects and nasal (during velum closure) and oral samples from the non-tracheostomised subjects. Measurements were performed before and after sodium nitrate ingestion (10 mg/kg) and use of antibacterial mouthwash (chlorhexidine 0.2%).
RESULTS In tracheostomised subjects oral FE(NO) increased by 90% (p<0.01) while tracheal FE(NO) was not affected 60 minutes after nitrate ingestion. Oral EBC nitrite levels were increased 23-fold at 60 minutes (p<0.001) whereas the nitrite levels in tracheal EBC showed only a minor increase (fourfold, p<0.05). Nitrate was increased the same amount in oral and tracheal EBC at 60 minutes (2.5-fold, p<0.05). In non-tracheostomised subjects oral FE(NO) and EBC nitrite increased after nitrate ingestion and after chlorhexidine mouthwash they approached baseline levels again (p<0.001). Nasal NO, nitrate, and nitrite were not affected by nitrate intake or mouthwash. At baseline, mouthwash with deionised water did not affect nitrite in oral EBC or saliva, whereas significant reductions were seen after antibacterial mouthwash (p<0.05 and p<0.001, respectively).
CONCLUSIONS Besides the salivary glands, plasma nitrate is taken up by the lower airways but not the nasal airways. Nitrate levels in EBC are thus influenced by dietary intake. Nitrate is reduced to nitrite by bacterial activity which takes place primarily in the oropharyngeal tract of healthy subjects. Only oropharyngeal nitrite seems to contribute to exhaled NO in non-inflamed airways, and there is also a substantial contribution of nitrite from the oropharyngeal tract during standard collection of EBC.
[A]: Origin of nitrite and nitrate in nasal and exhaled breath condensate and relation to nitric oxide formation.

[Q]: In many eukaryotes, RNA-dependent RNA polymerases (RdRPs) play key roles in the RNAi pathway. They have been implicated in the recognition and processing of aberrant transcripts triggering the process, and in amplification of the silencing response. We have tested the functions of RdRP genes from the ciliate Paramecium tetraurelia in experimentally induced and endogenous mechanisms of gene silencing. In this organism, RNAi can be triggered either by high-copy, truncated transgenes or by directly feeding cells with double-stranded RNA (dsRNA). Surprisingly, dsRNA-induced silencing depends on the putatively functional RDR1 and RDR2 genes, which are required for the accumulation of both primary siRNAs and a distinct class of small RNAs suggestive of secondary siRNAs. In contrast, a third gene with a highly divergent catalytic domain, RDR3, is required for siRNA accumulation when RNAi is triggered by truncated transgenes. Our data further implicate RDR3 in the accumulation of previously described endogenous siRNAs and in the regulation of the surface antigen gene family. While only one of these genes is normally expressed in any clonal cell line, the knockdown of RDR3 leads to co-expression of multiple antigens. These results provide evidence for a functional specialization of Paramecium RdRP genes in distinct RNAi pathways operating during vegetative growth.
[A]: Distinct RNA-dependent RNA polymerases are required for RNAi triggered by double-stranded RNA versus truncated transgenes in Paramecium tetraurelia

[Q]: BACKGROUND Knowledge, attitudes, and risk perception in relation to second primary cancer (SPC) screening and their impact on screening practices in cancer survivors are largely unknown.
METHODS A total of 326 cancer survivors who had completed primary treatment for cancer >1 year previously were recruited from 6 oncology care outpatient clinics in the Republic of Korea. Survivors' knowledge, attitudes, perceived risk, and screening practices were assessed along with sociodemographic, behavioral, and clinical characteristics. Multivariate logistic regression was used to examine behavioral factors associated with the completion of all appropriate SPC screening according to national guidelines.
RESULTS Approximately 37.7% of survivors had undergone all appropriate SPC screening tests. Survivors were found to have a high perceived risk of SPC, high perceived benefits of screening, and positive attitudes toward cancer screening. However, they had limited knowledge regarding SPC screening tests and few had received a recommendation from a physician to undergo SPC screening. Although there was no association found between perceived risk and positive attitudes with screening behavior, higher knowledge was noted to be significantly associated with the completion of all appropriate SPC screening (adjusted odds ratio, 1.81; 95% confidence interval, 1.03-3.33).
CONCLUSIONS In the current study, cancer survivors were found to have limited knowledge regarding second cancer screening tests, which may have resulted in lower rates of completion of screening practices in this population.
[A]:
Knowledge, attitudes, risk perception, and cancer screening behaviors among cancer survivors.