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Abstract Background Centromeres are essential for chromosome segregation, yet their DNA sequences evolve rapidly. In most animals and plants that have been studied, centromeres contain megabase-scale arrays of tandem repeats. Despite their importance, very little is known about the degree to which centromere tandem repeats share common properties between different species across different phyla. We used bioinformatic methods to identify high-copy tandem repeats from 282 species using publicly available genomic sequence and our own data. Results Our methods are compatible with all current sequencing technologies. Long Pacific Biosciences sequence reads allowed us to find tandem repeat monomers up to 1,419 bp. We assumed that the most abundant tandem repeat is the centromere DNA, which was true for most species whose centromeres have been previously characterized, suggesting this is a general property of genomes. High-copy centromere tandem repeats were found in almost all animal and plant genomes, but repeat monomers were highly variable in sequence composition and length. Furthermore, phylogenetic analysis of sequence homology showed little evidence of sequence conservation beyond approximately 50 million years of divergence. We find that despite an overall lack of sequence conservation, centromere tandem repeats from diverse species showed similar modes of evolution. Conclusions While centromere position in most eukaryotes is epigenetically determined, our results indicate that tandem repeats are highly prevalent at centromeres of both animal and plant genomes. This suggests a functional role for such repeats, perhaps in promoting concerted evolution of centromere DNA across chromosomes.

Drones operating in an urban environment pose a potential collision threat to rotorcraft. In this paper, the battery pack of the DJI MAVIC 2 ZOOM is analyzed since the battery is considered to be the greatest threat due to its high weight and stiffness. Following a pyramid-type building block approach, a high-fidelity model simulation was developed for LSDYNA based on a wide range of experiments, ranging from quasi-static material tests to quasi-static component tests up to high-velocity impact experiments. The high-fidelity model allows the prediction of damage in potential collision scenarios between a high-speed rotorcraft and the battery pack of the drone. For the particular impact configuration analyzed within this paper, the drone battery does not cause catastrophic failure of the windshield of the rotorcraft. [ABSTRACT FROM AUTHOR]

Background: Men of African descent are disproportionately affected by prostate cancer (PCa), and many have metastatic disease at presentation. In South Africa (SA), androgen deprivation therapy (ADT) is the first-line treatment for stage IV PCa. Objective: To identify predictors of overall survival (OS) in Black South African men with stage IV PCa treated with ADT. Design, Setting, and Participants: Men diagnosed with prostate cancer (3/22/2016–10/30/2020) at Chris Hani Baragwanath Academic Hospital in Soweto, Johannesburg, were recruited for the Men of African Descent with Cancer of the Prostate study. We included men with newly diagnosed stage IV PCa treated with ADT who had a prostate-specific antigen (PSA) level drawn prior to initiation of ADT and had ≥1 PSA drawn ≥12weeks after ADT start. Outcomes Measures and Statistical Analysis: We used Kaplan–Meier statistics to estimate OS and Cox regression models to identify predictors of OS. Results and Limitations: Of the 1097 men diagnosed with prostate cancer, we included 153 men with stage IV PCa who received ADT and met PSA requirements. The median age was 68.0 years (interquartile range 64–73 years). Median OS from time of ADT initiation was 3.39 years (95% confidence interval (CI): 3.14%–noncalculable), while biochemical progression-free survival was 2.36 years (95% CI: 2.03%–3.73%). Biochemical progression (HR 3.52, 95% CI: 1.85%–6.70%), PSA nadir level >4ng/mL (HR 3.77, 95% CI: 1.86%–7.62%), alkaline phosphatase level at diagnosis >150 IU/dL (HR 3.09, 95% CI: 1.64%– 5.83%), and hemoglobin at diagnosis <13.5 g/dL (HR 2.90, 95% CI: 1.28%–6.56%) were associated with worse OS. Conclusions: In this study, we identified factors associated with poor OS among Black South African men with stage IV PCa treated with ADT. These factors may be useful in identifying patients for upfront treatment escalation, including the use of docetaxel chemotherapy or escalation of therapy at the time of biochemical progression. Patient Summary: In this study, we found that high alkaline phosphatase level, anemia at diagnosis, and high PSA nadir after initiation of androgen deprivation therapy are associated with worse overall survival among Black South African men treated with androgen deprivation therapy for metastatic prostate cancer. [ABSTRACT FROM AUTHOR]

Written in the immediate aftermath of the fall of the Soviet Union, the document contains discussion about possible future trajectories for cooperation over Nuclear weapons. Seeing neither the grounds for continued competition nor immediate cooperation, the authors prescribe a path of cautious engagement in cooperative measures to diminish any nuclear threat.