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"Yang, H."
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Imipramine blue halts head and neck cancer invasion through promoting F-box and leucine-rich repeat protein 14-mediated Twist1 degradation
The unique characteristic of head and neck squamous cell carcinoma (HNSCC) is that local invasion rather than distant metastasis is the major route for dissemination. Therefore, targeting the locally invasive cancer cells is more important than preventing systemic metastasis in HNSCC and other invasive-predominant cancers. We previously demonstrate a specific mechanism for HNSCC local invasion: the epithelial–mesenchymal transition (EMT) regulator Twist1 represses microRNA let-7i expression, leading to the activation of the small GTPase Rac1 and engendering the mesenchymal-mode movement in three-dimensional (3D) culture. However, targeting the EMT regulator is relatively difficult because of its transcription factor nature and the strategy for confining HNSCC invasion to facilitate local treatment is limited. Imipramine blue (IB) is a newly identified anti-invasive compound that effectively inhibits glioma invasion. Here we demonstrate that in HNSCC cells, a noncytotoxic dose of IB represses mesenchymal-mode migration in two-and-a-half-dimensional/3D culture system. IB suppresses EMT and stemness of HNSCC cells through inhibition of Twist1-mediated let-7i downregulation and Rac1 activation and the EMT signalling. Mechanistically, IB inhibits reactive oxygen species-induced nuclear factor-κB pathway activation. Importantly, IB promotes degradation of the EMT inducer Twist1 by enhancing F-box and leucine-rich repeat protein 14 (FBXL14)-mediated polyubiquitination of Twist1. Together, this study demonstrates the potent anti-invasion and EMT-inhibition effect of IB, suggesting the potential of IB in treating local invasion-predominant cancers.
Journal Article
A peculiarly short-duration gamma-ray burst from massive star core collapse
Gamma-ray bursts (GRBs) have been phenomenologically classified into long and short populations based on the observed bimodal distribution of duration
1
. Multi-wavelength and multi-messenger observations in recent years have revealed that in general long GRBs originate from massive star core collapse events
2
, whereas short GRBs originate from binary neutron star mergers
3
. It has been known that the duration criterion is sometimes unreliable, and multi-wavelength criteria are needed to identify the physical origin of a particular GRB
4
. Some apparently long GRBs have been suggested to have a neutron star merger origin
5
, whereas some apparently short GRBs have been attributed to genuinely long GRBs
6
whose short, bright emission is slightly above the detector’s sensitivity threshold. Here, we report the comprehensive analysis of the multi-wavelength data of the short, bright GRB 200826A. Characterized by a sharp pulse, this burst shows a duration of 1 second and no evidence of an underlying longer-duration event. Its other observational properties such as its spectral behaviours, total energy and host galaxy offset are, however, inconsistent with those of other short GRBs believed to originate from binary neutron star mergers. Rather, these properties resemble those of long GRBs. This burst confirms the existence of short-duration GRBs with stellar core-collapse origin
4
, and presents some challenges to the existing models.
A gamma-ray burst (GRB) is reported to show a sharp 1-second spike, characteristic of short GRBs, but with other observational properties resembling those of long GRBs. This burst may belong to a class of core-collapse-origin GRBs with genuinely short durations.
Journal Article
Interface control of bulk ferroelectric polarization
The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.
Journal Article
Proton pump inhibitors and risk of hip fracture: a meta-analysis of observational studies
SummaryWe performed a meta-analysis of relevant studies to quantify the magnitude of the association between proton pump inhibitors (PPIs) and risk of hip fracture. Patients with PPIs had a greater risk of hip fracture than those without PPI therapy (RR 1.20, 95% CI 1.14–1.28, p < 0.0001). These results could be taken into consideration with caution, and patients should also be concerned about the inappropriate use of PPIs.IntroductionProton pump inhibitors (PPIs) are generally considered as first-line medicine with great safety profile, commonly prescribed for gastroesophageal reflux disease (GERD) and peptic ulcer disease. However, several epidemiological studies documented that long-term use of PPIs may be associated with an increased risk of hip fracture. Although, the optimal magnitude of the hip fracture risk is still undetermined. We, therefore, performed a meta-analysis of relevant studies to quantify the magnitude of the association between PPIs and risk of hip fracture.MethodsWe collected relevant articles using MEDLINE, EMBASE, Google Scholar, and Web of Science from January 1, 1990, to March 31, 2018. We included only the large (n ≥ 500) observational studies with a follow-up duration of at least one year in which the hip fracture patients were identified by a standard procedure. Two of the authors extracted data from each included study independently according to a standardized protocol.ResultsA total of 24 observational studies with 2,103,800 participants (319,568 hip fracture patients) met all the eligibility criteria. Patients with PPIs had a greater risk of hip fracture than those without PPI therapy (RR 1.20, 95% CI 1.14–1.28, p < 0.0001). An increased association was also observed in both low and medium doses of PPI taken and hip fracture risk (RR 1.17, 95% CI 1.05–1.29, p = 0.002; RR 1.28, 95% CI 1.14–1.44, p < 0.0001), but it appeared to be even greater among the patients with higher dose (RR 1.30, 95% CI 1.20–1.40, p < 0.0001). Moreover, the overall pooled risk ratios were 1.20 (95% CI 1.15–1.25, p < 0.0001) and 1.24 (95% CI 1.10–1.40, p < 0.0001) for the patients with short- and long-term PPI therapy, respectively, compared with PPI non-users.ConclusionOur results suggest that PPI use is significantly associated with an increased risk of hip fracture development, which is not observed in H2RA exposure. Physicians should, therefore, exercise caution when considering a long-term PPI treatment to their patients who already have an elevated risk of hip fracture. In addition, patients should be concerned about the inappropriate use of PPIs; if necessary, then, they should continue to receive it with a clear indication.
Journal Article
Benchmarking clustering algorithms on estimating the number of cell types from single-cell RNA-sequencing data
Background
A key task in single-cell RNA-seq (scRNA-seq) data analysis is to accurately detect the number of cell types in the sample, which can be critical for downstream analyses such as cell type identification. Various scRNA-seq data clustering algorithms have been specifically designed to automatically estimate the number of cell types through optimising the number of clusters in a dataset. The lack of benchmark studies, however, complicates the choice of the methods.
Results
We systematically benchmark a range of popular clustering algorithms on estimating the number of cell types in a variety of settings by sampling from the Tabula Muris data to create scRNA-seq datasets with a varying number of cell types, varying number of cells in each cell type, and different cell type proportions. The large number of datasets enables us to assess the performance of the algorithms, covering four broad categories of approaches, from various aspects using a panel of criteria. We further cross-compared the performance on datasets with high cell numbers using Tabula Muris and Tabula Sapiens data.
Conclusions
We identify the strengths and weaknesses of each method on multiple criteria including the deviation of estimation from the true number of cell types, variability of estimation, clustering concordance of cells to their predefined cell types, and running time and peak memory usage. We then summarise these results into a multi-aspect recommendation to the users. The proposed stability-based approach for estimating the number of cell types is implemented in an R package and is freely available from (
https://github.com/PYangLab/scCCESS
).
Journal Article
Fermi and eROSITA bubbles as relics of the past activity of the Galaxy’s central black hole
The newly launched X-ray satellite, eROSITA, has recently revealed two gigantic bubbles extending to ~80° above and below the Galactic Centre. The morphology of these ‘eROSITA bubbles’ bears a remarkable resemblance to the Fermi bubbles previously discovered by the Fermi Gamma-ray Space Telescope and its counterpart, the microwave haze. The physical origin of these striking structures has been intensely debated; however, because of their symmetry about the Galactic Centre, they probably originate from some energetic outbursts from the Galactic Centre in the past. Here we propose a theoretical model in which the eROSITA bubbles, Fermi bubbles and the microwave haze could be simultaneously explained by a single event of jet activity from the central supermassive black hole a few million years ago. Using numerical simulations, we show that this model could successfully reproduce the morphology and multi-wavelength spectra of the observed bubbles and haze, which allows us to derive critical constraints on the energetics and timescales of the outburst. This study serves as an important step forward in our understanding of the past Galactic Centre activity of our own Galaxy and may bring valuable insights into the broader picture of supermassive-black-hole–galaxy co-evolution in the context of galaxy formation.
The newly discovered eROSITA X-ray bubbles in the Milky Way’s centre, together with the Fermi bubbles and microwave haze, may be explained by a single episode of central supermassive-black-hole jet activity a few million years ago.
Journal Article
Individually addressed entangling gates in a two-dimensional ion crystal
Two-dimensional (2D) ion crystals may represent a promising path to scale up qubit numbers for ion trap quantum information processing. However, to realize universal quantum computing in this system, individually addressed high-fidelity two-qubit entangling gates still remain challenging due to the inevitable micromotion of ions in a 2D crystal as well as the technical difficulty in 2D addressing. Here we demonstrate two-qubit entangling gates between any ion pairs in a 2D crystal of four ions. We use symmetrically placed crossed acousto-optic deflectors (AODs) to drive Raman transitions and achieve an addressing crosstalk error below 0.1%. We design and demonstrate a gate sequence by alternatingly addressing two target ions, making it compatible with any single-ion addressing techniques without crosstalk from multiple addressing beams. We further examine the gate performance versus the micromotion amplitude of the ions and show that its effect can be compensated by a recalibration of the laser intensity without degrading the gate fidelity. Our work paves the way for ion trap quantum computing with hundreds to thousands of qubits on a 2D ion crystal.
Quantum gates in 2D ion crystals are more challenging than in 1D. Here, the authors use their 2D ion trap platform and acousto-optical deflectors to demonstrate a 2-qubit gate that can stand the ion micromotion in such configuration.
Journal Article