Weather Forecast of the Milky Way: Shear and Stellar feedback determine the lives of Galactic-scale filaments

The interstellar medium (ISM) is an inseparable part of the Milky Way ecosystem whose evolutionary history remains a challenging question. We trace the evolution of the molecular ISM using a sample of Young Stellar Objects (YSO) association --molecular cloud complex (YSO-MC complex). We derive their three-dimensional (3D) velocities by combining the Gaia astrometric measurements of the YSO associations and the CO observations of the associated molecular clouds. Based on the 3D velocities, we simulate the motions of the YSO-MC complexes in the Galactic potential and forecast the ISM evolution by tracing the motions of the individual complexes, and reveal the roles of shear and stellar feedback in determining ISM evolution: Galactic shear stretches Galactic-scale molecular cloud complexes, such as the G120 Complex, into Galactic-scale filaments, and it also contributes to the destruction of the filaments; while stellar feedback creates interconnected superbubbles whose expansion injects peculiar velocities into the ISM. The Galactic-scale molecular gas clumps are often precursors of the filaments and the Galactic-scale filaments are transient structures under a constant stretch by shear. This evolutionary sequence sets a foundation to interpret other gas structures. Animations are available at https://gxli.github.io/ISM-6D/movie.html.Comment: Accepted by MNRAS letter

Path Integral Based Convolution and Pooling for Graph Neural Networks

Graph neural networks (GNNs) extends the functionality of traditional neural networks to graph-structured data. Similar to CNNs, an optimized design of graph convolution and pooling is key to success. Borrowing ideas from physics, we propose a path integral based graph neural networks (PAN) for classification and regression tasks on graphs. Specifically, we consider a convolution operation that involves every path linking the message sender and receiver with learnable weights depending on the path length, which corresponds to the maximal entropy random walk. It generalizes the graph Laplacian to a new transition matrix we call maximal entropy transition (MET) matrix derived from a path integral formalism. Importantly, the diagonal entries of the MET matrix are directly related to the subgraph centrality, thus providing a natural and adaptive pooling mechanism. PAN provides a versatile framework that can be tailored for different graph data with varying sizes and structures. We can view most existing GNN architectures as special cases of PAN. Experimental results show that PAN achieves state-of-the-art performance on various graph classification/regression tasks, including a new benchmark dataset from statistical mechanics we propose to boost applications of GNN in physical sciences.Comment: 15 pages, 4 figures, 6 tables. arXiv admin note: text overlap with arXiv:1904.1099

Formononetin promotes apoptosis of colorectal cancer cells via activation of mitochondria-dependent MAPK pathway

Purpose: To investigate whether formononetin exhibits antitumor activity in colorectal cancer cell lines via the mitochondria-dependent mitogen-activated protein kinase (MAPK) pathway.Methods: Human colorectal cells were treated with various doses of formononetin for 24 h, followed by Cell Counting Kit-8 (CCK-8) assay and western blot. Human colorectal cells were incubated with equivalent vehicle (DMSO) or 100 μM formononetin for 24 h, followed by nuclear staining with propidium iodide (PI) and diamidino-2-phenylindole (DAPI) for analyses of apoptosis. Human colorectal cells were incubated with equivalent vehicle or 100 μM formononetin for 24 h followed by analysis of cell migration and invasion. Human colorectal cells were incubated with equivalent vehicle (DMSO) or 100 μM formononetin for various duration (3, 6, 12, and 24 h), followed by detection of intracellular reactive oxygen species (ROS) level and measurement of mitochondrial membrane potential (Δψm) to monitor mitochondria functionality.Results: In human colorectal cancer cell lines SW1463 and T84, formononetin (> 20 μM) significantly inhibited cell growth (p < 0.05) in a dose-dependent manner, noticeably induced apoptosis, and suppressed cell migration and invasion. Western blot analysis revealed that formononetin treatment caused significantly increased levels of proapoptotic proteins, and suppression of cell proliferationrelated protein and matrix metallopeptidases (MMP) levels. Formononetin also induced mitochondrial depolarization and ROS generation in a time-dependent manner, indicating that formononetin mediates human colorectal cancer cell apoptosis via activation of MAPK pathway in a dose-dependent manner.Conclusion: Formononetin induces human colorectal cancer cell apoptosis via mitochondriadependent MAPK pathway, thus lending experimental support for the clinical application of formononetin for colorectal cancer therapy.Keywords: Formononetin, Colorectal cancer, Mitochondria, Reactive oxygen species, Cytochrome C, Mitogen-activated protein kinas

Toksičnost aromatskih ketona za stanice kvasca i ubrzanje njihove redukcije primjenom adsorpcijskih smola

Asymmetric reduction of the prochiral aromatic ketone catalyzed by yeast cells is one of the most promising routes to produce its corresponding enantiopure aromatic alcohol, but the space-time yield does not meet people’s expectations. Therefore, the toxicity of aromatic ketone and aromatic alcohol to the yeast cell is investigated in this work. It has been found that the aromatic compounds are poisonous to the yeast cell. The activity of yeast cell decreases steeply when the concentration of acetophenone (ACP) is higher than 30.0 mmol/L. Asymmetric reduction of acetophenone to chiral S-α-phenylethyl alcohol (PEA) catalyzed by the yeast cell was chosen as the model reaction to study in detail the promotion effect of the introduction of the resin adsorption on the asymmetric reduction reaction. The resin acts as the substrate reservoir and product extraction agent in situ. It has been shown that this reaction could be remarkably improved with this technique when the appropriate kind of resin is applied. The enantioselectivity and yield are acceptable even though the initial ACP concentration reaches 72.2 mmol/L.Asimetrična redukcija prokiralnih aromatskih ketona, katalizirana stanicama kvasca, obećavajuća je metoda proizvodnje enantiomerno čistih aromatskih alkohola, no iskorištenje reakcije ne zadovoljava današnje potrebe. U radu je utvrđena toksičnost aromatskih ketona i alkohola za stanice kvasca. Aktivnost stanica kvasca naglo se smanjila pri koncentracijama acetofenona većim od 30 mmol/L. Kao model reakcije za detaljno ispitivanje pozitivnog učinka uvođenja adsorpcijskih smola odabrana je asimetrična redukcija acetofenona u kiralni S-α-feniletilni alkohol, katalizirana stanicama kvasca. Utvrđeno je da smola djeluje kao rezervoar supstrata i agens za ekstrakciju proizvoda in situ. Tako se odvijanje reakcije može znatno poboljšati uvođenjem prikladne smole. Enantioselektivnost i prinos su zadovoljavajući iako je početna koncentracija acetofenona dosegla čak 72,2 mmol/L

Comparative proteomics study on liver mitochondria of primary biliary cirrhosis mouse model

BACKGROUND: Primary biliary cirrhosis (PBC) is a liver specific chronic disease with unclear pathogenesis, especially for the early stage molecular events. The mitochondrion is a multi-functional organelle associated with various diseases including PBC. The purpose of this study was to discover the alterations in the mitochondria proteome using an early stage PBC mouse model for revealing the possible pathogenesis mechanisms in the early stages of PBC. METHODS: Mouse model of early stage of PBC was constructed by consecutive administration of poly I:C. Mitochondria of mouse models and controls were purified and comparative proteomics was performed by iTRAQ technology. Then, differentially expressed proteins were validated by western blotting. RESULTS: In total 354 proteins that satisfied the criteria for comparative proteomics study were identified. Of them, nine proteins were downregulated and 20 were up-regulated in liver mitochondria of PBC mouse model. Most differentially expressed proteins are associated with oxidation-reduction and lipid metabolism, and some are involved in the biosynthesis of steroid hormone and primary bile acid. Interestingly, four proteins (HCDH, CPT I, DECR, ECHDC2) involved in the fatty acid beta-oxidation were all upregulated. CONCLUSIONS: iTRAQ is a powerful tool for comparative proteomics study of PBC mouse model and differentially expressed proteins in mitochondria proteome of PBC mouse model provide insights for the pathogenesis mechanism at early stage of PBC

Numerical computation of the flow noise for the centrifugal pump with considering the impeller outlet width

In order to study the effects of the impeller outlet width on the flow noise of the centrifugal pump, a centrifugal pump is applied in the paper as the research object. Geometric parameters of the pump and impeller are constant, and BEM (Boundary Element Method) and experimental method are adopted to analyze noises when the impeller outlet width is 8 mm, 10 mm, 12 mm and 14 mm, respectively. Firstly, Large-eddy simulation method is applied to compute the transient flow field of the centrifugal pump. Larger pressures and flow velocity of the centrifugal pump mainly are at the edge of the impeller. When the fluid flows from the centrifugal pump, there are two obvious separation vortexes at the outlet of the centrifugal pump. The flow velocity distribution of the centrifugal pump in the horizontal plane is basically symmetric. Based on modal analysis and the transient flow field of the pump, BEM is adopted to compute the noise in the centrifugal pump caused by the unsteady flow, and experiments are also conducted for verification. Based on the above analysis, the noise in the interior and exterior field of the centrifugal pump is computed, and the effects of the impeller outlet width on the noise of the centrifugal pump are then studied. As shown from the result, the radiation sound power at the characteristic frequency increases with the increase of the impeller outlet width. With a reasonable range, the impeller outlet width makes the sound pressure level (SPL) in the interior and external field of various flow conditions be smaller. Considering the energy performance and flow field noises of the centrifugal pump, the pump has the optimal comprehensive performance at the impeller outlet width of 10 mm. The research results can be applied to provide a reference for the optimization design of the centrifugal pump with low vibration and noise

Is tea consumption associated with the serum uric acid level, hyperuricemia or the risk of gout? A systematic review and meta-analysis

The methodological quality of cross-sectional studies in accordance with the Newcastle-Ottawa Scale (NOS). Table S2. The methodological quality of cohort studies in accordance with the Newcastle-Ottawa Scale (NOS). Table S3. The methodological quality of case–control studies in accordance with the Newcastle-Ottawa Scale (NOS). (DOCX 19 kb