In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

[Q]: Phenanthroquinolizidine alkaloids a b s t r a c t The stereoselective synthesis of epi-thieno analogues of the phenanthroquinolizidine bioactive alkaloids (À)-Cryptopleurine and (À)-(15R)-Hydroxycryptopleurine was achieved in five steps starting from easily available enantiopure (S)-2-aminoadipic acid used as chiral pool and nitrogen atom source. During these investigations, both p-cationic cyclization of chiral N-thienylmethyl-6-oxopipecolinic acids into pure (S)keto-lactams and theirs regioselective and diastereoselective reduction, considered as key steps of this sequence, were studied. Of particular interest, the FriedeleCrafts cyclization using (CF 3 CO) 2 O/BF 3 $Et 2 O show that near the expected keto-lactams, enamides and enamidones containing trifluoromethyl residue were isolated. A mechanism leading to the latter products with high synthetic potential was discussed.
[A]: Use of chiral-pool approach into epi-thieno analogues of the scarce bioactive phenanthroquinolizidine alkaloids


[Q]: Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV) was originally identified in Saudi Arabia in 2012. It has caused MERS outbreaks with high mortality in the Middle East and Europe, raising a serious concern about its pandemic potential. Therefore, development of effective vaccines is crucial for preventing its further spread and future pandemic. Our previous study has shown that subcutaneous (s.c.) vaccination of a recombinant protein containing receptor-binding domain (RBD) of MERS-CoV S fused with Fc of human IgG (RBD-Fc) induced strong systemic neutralizing antibody responses in vaccinated mice. Here, we compared local and systemic immune responses induced by RBD-Fc via intranasal (i.n.) and s.c. immunization pathways. We found that i.n. vaccination of MERS-CoV RBD-Fc induced systemic humoral immune responses comparable to those induced by s.c. vaccination, including neutralizing antibodies, but more robust systemic cellular immune responses and significantly higher local mucosal immune responses in mouse lungs. This study suggests the potential of developing MERS-CoV RBD protein into an effective and safe mucosal candidate vaccine for prevention of respiratory tract infections caused by MERS-CoV.
[A]: Intranasal vaccination with recombinant receptor-binding domain of MERS-CoV spike protein induces much stronger local mucosal immune responses than subcutaneous immunization: Implication for designing novel mucosal MERS vaccines


[Q]: Background: Dental caries is a preventable childhood disease, but public health efforts are hampered due to limited information on associated factors in vulnerable populations. Our study was aimed at estimating the prevalence of dental caries and identifying key associated factors in four major risk domains, including socioeconomic factors, child oral health behavior and practices, child feeding practices, and dietary habits among primary school children in Saudi Arabia. A cross-sectional study design was used to recruit 578 male Saudi primary school children, aged 6-8 years, from 12 primary schools in five different regions of Riyadh. Children were clinically screened to detect carious lesions in primary teeth according to World Health Organization's criteria. Structured self-administered questionnaire was used to collect information on social and individual factors from the parents. The odds ratios and 95% confidence intervals of associated factors for dental caries were computed using logistic regression models; key factors were identified by systematic selection process that accounted for multicollinearity and bias correction. Results: Dental caries was prevalent among children (83%, 95% confidence interval 79.7-86.0%). Individual factors, including irregular brushing, late adoption of brushing habit, consulting dentist for symptomatic treatment, lack of breast feeding, sleeping with a bottle in mouth, habit of snacking between meals, low consumption of fruits, and frequent consumption of soft drinks and flavored milk, were predominantly associated with dental caries in children, instead of socioeconomic factors (p < 0.05, adjusted R-square 80%). Conclusion: Dental caries were prevalent in school children, and individual factors were predominantly associated with the disease.
[A]:
Prevalence of dental caries and associated factors among primary school children: a population-based cross-sectional study in Riyadh, Saudi Arabia