431 research outputs found

    Identification and Phenotypic Plasticity of Metastatic Cells in a Mouse Model of Melanoma

    Get PDF
    Melanoma is the deadliest form of skin cancer due to its high propensity to metastasize and resistance to current therapies. We have created a spontaneous mouse model of metastatic melanoma (Dct-Grm1/K5-Edn3) where metastasis to the lungs is 80% penetrant. The primary tumors of these mice present cellular heterogeneity with cells at varying levels of differentiation. The main goal of this study was to determine the metastatic potential of the primary tumor resident Tyrosinase positive cells and evaluate the dynamic phenotypic changes as those cells move from the primary tumors to the sites of metastasis. To accomplish this aim I crossed the Dct-Grm1/K5-Edn3 mice to CreERT2/mT/mG mice to indelibly label Tyrosinase cell populations within the primary tumor with Green Fluorescent Protein (GFP) by topical application of 4-hydroxytamoxifen (4HT) at the tumor site. In vivo lineage tracing and characterization of GFP+ cells were performed in the metastatic lesions. In the 4HT treated Dct-Grm1/ K5-Edn3/Tyr-CreERT2/mT/mG mice, primary tumor derived Tyrosinase positive cells or their progeny (GFP+) established successful metastases in the distant organs indicating the tumorigenic capacity of the differentiated cell populations. Numerous metastatic melanoma cells were identified in the vasculature of the metastatic organs and established close association with the vascular endothelium. The intravascular cells lost pigmentation and did not express melanocytic markers; however, they mimicked endothelial cell properties and gained the expression of CD31 (also known as platelet endothelial cell adhesion molecule PECAM-1) and vascular endothelial (VE)-Cadherin. In the lung metastatic foci, GFP+ cells resumed pigmentation production and lost the expression of endothelial cell markers. Evidence from other metastatic organs in the mice further supported the phenotypic plasticity of metastatic melanoma cells. The in vivo lineage tracing system established in the melanoma mouse model revealed tumor phenotypic plasticity and will be a powerful model to evaluate and help us understand the etiology and pathogenesis of melanoma metastasis. Further characterization of those more aggressive cells in melanoma will allow for the development of new prognostic tests and novel therapeutic strategies to eliminate metastasis

    Learning a Dilated Residual Network for SAR Image Despeckling

    Full text link
    In this paper, to break the limit of the traditional linear models for synthetic aperture radar (SAR) image despeckling, we propose a novel deep learning approach by learning a non-linear end-to-end mapping between the noisy and clean SAR images with a dilated residual network (SAR-DRN). SAR-DRN is based on dilated convolutions, which can both enlarge the receptive field and maintain the filter size and layer depth with a lightweight structure. In addition, skip connections and residual learning strategy are added to the despeckling model to maintain the image details and reduce the vanishing gradient problem. Compared with the traditional despeckling methods, the proposed method shows superior performance over the state-of-the-art methods on both quantitative and visual assessments, especially for strong speckle noise.Comment: 18 pages, 13 figures, 7 table

    Research on selectivity removing SO2 from flue gas with a novel absorbent

    Get PDF
    Compared with the traditional methods of removal SO2 from flue gas, the organic solvent absorption has some advantages as low investment, high SO2 absorption efficiency and desorption efficiency. For the industrial application of organic solvent absorption as soon as possible, some laboratory research on selectively removing SO2 and NOx from flue gas in the presence of CO2 and an enlarged experiment has been done with a novel absorbent of Mn(II)+ DMSO. The effect on desulfurization selectivity for absorbents is studied. And the regeneration capacities for absorbent are researched. The result shows that the novel absorbent has not only strong desulfurization efficiency, but also good selectivity for SO2 and CO2, the feasibility of desulfurization absorbent has been proved

    Study on the Technology Conditions of Flue Gas Desulfurization with Organic Solvent

    Get PDF
    The technology experiment on Flue Gas Desulfurization (FDG) by DMSO method is studied in this paper, and the desulfurization efficiency is set out in various conditions. The results show that the desulfurization efficiency can be over 94% under the condition as follows: the rate of flow of DMSO=100 L/h, L/Gï¼40~50, absorbent concentration = 100 %DMSO, T=room temperature, the gas flow=60 ml∙min-1, inlet SO2 concentration= 0.1-0.5 %, the time of operation must be controlled in 30 minutes

    Study on development of low-carbon building based on LCA

    Get PDF
    AbstractThis text did a research about the status of low-carbon technologies in building area, and discussed the necessity and importance of reducing carbon emissions in the full life cycle of building; constructed low-carbon assessment model of building; Explored the development of low carbon construction law field, and thus identified the difficulties and challenges faced in its development, finding effective ways and providing a theoretical basis for the healthy and rapid development of low-carbon buildings

    LIQUID-SOLID COUPLING RESPONSE OF SURROUNDING ROCK MASS OF LARGE-DIAMETER RIVER-CROSSING SHIELD TUNNEL

    Get PDF
    The purpose is to investigate the response of seepage field, displacement field and stress field in the surrounding rock mass during dynamic tunneling in soft soil area. Relied on a large-diameter river-crossing shield tunnel project, considering driving force, shield tail grouting pressure, and the friction resistance between the shield shell and the soil, a three-dimensional fine tunnel model considering the liquid-solid coupling effect in the soil during dynamic tunneling was established by employing the finite difference method. The response characteristics of pore water pressure, displacement and stress in the surrounding rock mass were obtained. The results show that during shield tunneling and shield tail grouting, the pore water pressure in the range of 0.5 times the hole diameter around the tunnel decreases and increases respectively due to the liquid-solid coupling in the surrounding rock mass. When the shield tunneling moves away, the pore water pressure of the soil near the vault decreases, and the pore water pressure near the tunnel arch bottom increases. The impact range of shield tail grouting on the vertical settlement of the upper soil is about 0.5 times the hole diameter. The shield tail grouting can effectively reduce the vertical settlement of the top soil and slow down the vertical uplift of the bottom soil. During shield tunneling the vertical stress distribution of the soil above the vault of the working position and around the excavation surface is funnel-shaped, and the vertical stress around the excavated tunnel decreases

    A preliminary study of in vitro and in vivo synergistic effects of ciprofloxacin and D-tyrosine against Pseudomonas aeruginosa isolates

    Get PDF
    Purpose: To investigate the synergistic antimicrobial effects of ciprofloxacin and D-tyrosine against drug-resistant bacteria.Method: The antimicrobial effects of ciprofloxacin and D-tyrosine on clinical isolates of multidrugresistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) no. 3556 were determined in vitro based on time-kill curve, and in vivo in P. aeruginosa-zebrafish infection model. Furthermore, 30 clinical isolates of multidrug-resistant P. aeruginosa were used in vitro to ascertain the synergistic effect of the two agents.Results: Combined use of ciprofloxacin and D-tyrosine produced synergistic effects against the clinical isolate of P. aeruginosa no. 3556 in vitro and in vivo. Synergism occurred in 96.67 % (95 % CI, range 83.33 - 99.41 %) of the clinical isolates, and ciprofloxacin dose was reduced in 90 % (95 % CI, range 74.38 - 96.54 %) of the clinical isolates in vitro.Conclusion: These preliminary results suggest that the combination of ciprofloxacin and D-tyrosine is a promising therapeutic strategy against MDR P. aeruginosa infections. Keywords: Ciprofloxacin, D-tyrosine, Synergistic, P. aeruginosa, Zebrafish infection model, Time-killing curv

    STRATA SUBSIDENCE CHARACTERISTICS OF SHIELD TUNNELING IN COASTAL SOFT SOIL AREA

    Get PDF
    In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form

    STRATA SUBSIDENCE CHARACTERISTICS OF SHIELD TUNNELING IN COASTAL SOFT SOIL AREA

    Get PDF
    In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form
    corecore