1,523 research outputs found

    BBR-induced Stark shifts and level broadening in helium atom

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    The precise calculations of blackbody radiation (BBR)-induced Stark shifts and depopulation rates for low-lying states of helium atom with the use of variational approach are presented. An effect of the BBR-induced induced Stark-mixing of energy levels is considered. It is shown that this effect leads to a significant reduction of lifetimes of helium excited states. As a consequence the influence of Stark-mixing effect on the decay rates of metastable states in helium is discussed in context of formation processes of the cosmic microwave background

    In vitro angiogenesis and expression of nuclear factor ÎșB and VEGF in high and low metastasis cell lines of salivary gland Adenoid Cystic Carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Adenoid cystic carcinoma is a high malignant carcinoma characterized by intensive local invasion and high incidence of distant metastasis. Although many reports have demonstrated that angiogenesis has played an important role in tumor metastasis, the relationship between metastasis characters and angiogenesis ability in high and low metastasis cell lines of Adenoid cystic carcinoma has rarely been reported. The present study aimed to compare the angiogenesis ability of ACC-M (high metastasis) and ACC-2 (low metastasis) cell lines in vitro. Furthermore, the activity of nuclear factor Îșappa B and the expression of vascular endothelial growth factor (VEGF) in ACC-2 and ACC-M were also detected.</p> <p>Methods</p> <p>Electrophoretic mobility shift assay was used to detect nuclear factor Îșappa B activity. Semi-quantitative RT-PCR was used to quantify the mRNA level of VEGF. Immuofluorescence double staining and semi-quantitative confocal laser scanning analysis was carried out to detect nuclear factor Îșappa B nuclear localization and staining intensity of VEGF. The angiogenesis ability of ACC-M and ACC-2 was compared by an in vitro three-dimensional angiogenic model assay. The vector transfection assay was performed to transfect the PCMV-IÎșBαM vector into ACCs cell lines expressing the phosphorylation defective IÎșBαM.</p> <p>Results</p> <p>Nuclear factor Îșappa B activity and the rate of nuclear factor Îșappa B nuclear localization in ACC-M was significantly higher than that in ACC-2. Moreover, ACC-M exhibited higher mRNA and protein levels of vascular endothelial growth factor than ACC-2. VEGF mRNA expression was effectively decreased by inhibition of nuclear factor Îșappa B activity. Furthermore, ACC-M could remarkably stimulate the migration and tube formation of endothelial cells and induce The umbilical vein endothelial cells sprouting into the gel matrix.</p> <p>Conclusion</p> <p>These results implicated that ACCs cells with higher metastasis feature might present greater angiogenesis ability.</p

    HIPK2 reduces the resistance of gastric cancer cells to cisplatin via p53 pathway

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    Purpose: To uncover the functional effect of homologous domain-associated protein kinase 2 (HIPK2) on the viability of cisplatin (DDP)-resistant gastric cancer (GC) cells and elucidate the possible mechanism of action.Methods: The effect of DDP on GC viability and apoptotic rate was evaluated using MTT and flow cytometry (FCM) assays. The potential effect of HIPK2 on DDP sensitivity and cell apoptosis was investigated in the presence of cisplatin while the effect of HIPK2 on p53 activation was determined by immunoblot assay.Results: HIPK2 expression was decreased in DDP-resistant GC cell while upregulation of HIPK2 reduced growth, but promoted apoptosis in DDP-resistant GC cells. Further investigations showed that HIPK2 promoted p53 activation, while suppression of p53 weakened the inhibitory effect of HIPK2 on DDP-resistance in GC cells.Conclusion: The results suggest that HIPK2 is a promising and important therapeutic factor for the regulation of the resistance of GC cells to DDP. Thus, may have a role to play in the management of gastric cancer Keywords: Gastric cancer, Cisplatin, HIPK2, Homologous domain-associated protein kinase 2, p53 pathway, Therapeutic targe

    Government regulation of emergency supplies under the epidemic crisis

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    This paper constructs a multi-oligopoly model of emergency supplies and analyses the market equilibrium results under normal conditions and epidemic conditions. The impacts of the degree of change in market demand, externalities, the material cost of emergency supplies and government regulation on the equilibrium results, especially on the prices of emergency supplies, are discussed. The results show that an increase in material cost will lead to low output and social welfare and a high price, under either normal conditions or epidemic conditions. Moreover, under epidemic conditions, the degree of change in market demand, externalities, material cost and the presence and mode of government regulation all have multiple and complex influences on the equilibrium results. Under epidemic conditions, both government output and price regulation can increase the supply of emergency supplies. In addition, when market demand changes drastically, consumer surplus and social welfare can be enhanced by the implementation of regulations. Particularly, price regulation is more effective when there is a high material cost

    Deep Dictionary Learning with An Intra-class Constraint

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    In recent years, deep dictionary learning (DDL)has attracted a great amount of attention due to its effectiveness for representation learning and visual recognition.~However, most existing methods focus on unsupervised deep dictionary learning, failing to further explore the category information.~To make full use of the category information of different samples, we propose a novel deep dictionary learning model with an intra-class constraint (DDLIC) for visual classification. Specifically, we design the intra-class compactness constraint on the intermediate representation at different levels to encourage the intra-class representations to be closer to each other, and eventually the learned representation becomes more discriminative.~Unlike the traditional DDL methods, during the classification stage, our DDLIC performs a layer-wise greedy optimization in a similar way to the training stage. Experimental results on four image datasets show that our method is superior to the state-of-the-art methods.Comment: 6 pages, 3 figures, 2 tables. It has been accepted in ICME202
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