Realization of a two-dimensional Weyl semimetal and topological Fermi strings.

A two-dimensional (2D) Weyl semimetal, akin to a spinful variant of graphene, represents a topological matter characterized by Weyl fermion-like quasiparticles in low dimensions. The spinful linear band structure in two dimensions gives rise to distinctive topological properties, accompanied by the emergence of Fermi string edge states. We report the experimental realization of a 2D Weyl semimetal, bismuthene monolayer grown on SnS(Se) substrates. Using spin and angle-resolved photoemission and scanning tunneling spectroscopies, we directly observe spin-polarized Weyl cones, Weyl nodes, and Fermi strings, providing consistent evidence of their inherent topological characteristics. Our work opens the door for the experimental study of Weyl fermions in low-dimensional materials.

Clinical outcomes of nirmatrelvir-ritonavir use in pregnant women during the Omicron wave of the coronavirus disease 2019 pandemic.

BACKGROUND: Paxlovid is an oral drug composed of nirmatrelvir and ritonavir that has been demonstrated to be effective in decreasing the risk of severe coronavirus disease 2019 (COVID-19). Here, we report the use of paxlovid in pregnant women with COVID-19. METHODS: Pregnant women attending a tertiary referral hospital in Taiwan from 29 April to 30 July 2022 were enrolled in the study. We compared baseline characteristics, clinical manifestations, and adverse events between paxlovid-treated women and those without paxlovid use. Maternal and neonatal outcomes were analysed in women who delivered during the study period. RESULTS: A total of 30 paxlovid-treated pregnant women and 55 women without paxlovid use were included in the analysis. The mean duration of COVID-19-associated symptoms in the paxlovid-treated women was shorter than that in the control group (10.10 days versus 15.59 days, p = 0.04). No severe adverse events due to paxlovid use were observed. Dysgeusia and diarrhoea were the most common adverse effects. Thirteen paxlovid-treated and 28 untreated women delivered during the study period. More pregnant women in the paxlovid group who delivered during the study period underwent caesarean delivery compared to the group without antiviral treatment (10 of 13 [76.92%] versus 12 of 28 [42.86%], p = 0.042), and insignificantly more newborns were born small for gestational age in the paxlovid group compared to the control group (3 of 13 [23.08%] versus 1 of 28 [3.57%], p = 0.086). CONCLUSION: Our study showed that paxlovid was effective and safe for pregnant women during the Omicron wave of the COVID-19 pandemic. A higher proportion of caesarean delivery rates was observed among paxlovid-treated women. Long-term follow-up of pregnant women exposed to paxlovid and their offspring is needed.

NVP-BEZ235, a dual PI3K-mTOR inhibitor, suppresses the growth of FaDu hypopharyngeal squamous cell carcinoma and has a synergistic effect with Cisplatin.

NVP-BEZ235 is a dual phosphoinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) inhibitor. A dual approach targeting more than one downstream effector is a promising strategy for treating cancers. The aim of this study was to evaluate the effect of NVP-BEZ235 in treating FaDu hypopharyngeal squamous cell carcinoma (HSCC), either alone or in combination with cisplatin. We found mTOR expression was higher in patients with HSCC. In the in vitro study, treatment with NVP-BEZ235 alone attenuated cell proliferation and suppressed p-p70S6K and p-4E-BP1 expression in FaDu cells. When NVP-BEZ235 was combined with Cisplatin, apoptosis was induced more effectively than with either drug alone. In mice with a FaDu xenograft, cotreatment with NVP-BEZ235 and Cisplatin engendered synergistic effects and produced a greater antitumor response than did treatment with either drug alone. Resected tumor samples also showed decreased p-p70S6K expression. Collectively, these data demonstrate that NVP-BEZ235 inhibits HSCC growth through phospho-p70S6K suppression and has a synergistic effect with Cisplatin in treating HSCC. The data also provide a strategy for more effective HSCC treatment.