In this task, you are given an abstract of article. Your task is to generate label "True" if abstract is structured, otherwise generate "False". A structured abstract is composed of a topic sentence (or key sentence), relevant supporting sentences, and a closing (or transition) sentence. This structure is key to keeping your abstract focused on the main idea and creating a clear and concise image.

Ex Input:
Topical preexposure prophylaxis interrupts HIV transmission at the site of mucosal exposure. Intermittently dosed vaginal gels containing the HIV-1 reverse transcriptase inhibitor tenofovir protected pigtailed macaques depending on the timing of viral challenge relative to gel application. However, modest or no protection was observed in clinical trials. Intravaginal rings (IVRs) may improve efficacy by providing long-term sustained drug delivery leading to constant mucosal antiretroviral concentrations and enhancing adherence. Although a few IVRs have entered the clinical pipeline, 100% efficacy in a repeated macaque vaginal challenge model has not been achieved. Here we describe a reservoir IVR technology that delivers the tenofovir prodrug tenofovir disoproxil fumarate (TDF) continuously over 28 d. With four monthly ring changes in this repeated challenge model, TDF IVRs generated reproducible and protective drug levels. All TDF IVR-treated macaques (n = 6) remained seronegative and simian-HIV RNA negative after 16 weekly vaginal exposures to 50 tissue culture infectious dose SHIV162p3. In contrast, 11/12 control macaques became infected, with a median of four exposures assuming an eclipse of 7 d from infection to virus RNA detection. Protection was associated with tenofovir levels in vaginal fluid [mean 1.8 10(5) ng/mL (range 1.1 10(4) to 6.6 10(5) ng/mL)] and ex vivo antiviral activity of cervicovaginal lavage samples. These observations support further advancement of TDF IVRs as well as the concept that extended duration drug delivery devices delivering topical antiretrovirals could be effective tools in preventing the sexual transmission of HIV in humans.

Ex Output:
False

Ex Input:
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.

Ex Output:
True

Ex Input:
In mammals, caloric restriction consistently results in extended lifespan. Epigenetic information encoded by DNA methylation is tightly regulated, but shows a striking drift associated with age that includes both gains and losses of DNA methylation at various sites. Here, we report that epigenetic drift is conserved across species and the rate of drift correlates with lifespan when comparing mice, rhesus monkeys, and humans. Twenty-two to 30-year-old rhesus monkeys exposed to 30% caloric restriction since 7-14 years of age showed attenuation of age-related methylation drift compared to ad libitum-fed controls such that their blood methylation age appeared 7 years younger than their chronologic age. Even more pronounced effects were seen in 2.7-3.2-year-old mice exposed to 40% caloric restriction starting at 0.3 years of age. The effects of caloric restriction on DNA methylation were detectable across different tissues and correlated with gene expression. We propose that epigenetic drift is a determinant of lifespan in mammals. Caloric restriction has been shown to increase lifespan in mammals. Here, the authors provide evidence that age-related methylation drift correlates with lifespan and that caloric restriction in mice and rhesus monkeys results in attenuation of age-related methylation drift.

Ex Output:
False