Background Accumulating evidence demonstrates the oncogenic roles of lncRNA (long non-coding RNA) molecules in a wide variety of cancer types including glioma. Equally important, However, tumorigenic functions of lncRNA in glioma remain largely unclear. A recent study suggested lncRNA SNHG15 played a role for regulating angiogenesis in glioma but its role in the tumor microenvironment (TME) was not investigated. Methods First, we showed that SNHG15 was upregulated in GBM cells and associated with a poor prognosis for the patients of GBM using public databases. Next, we collected temozolomide sensitive (TMZ-S) and resistant (TMZ-R) clinical samples and demonstrated that co-culturing TMZ-R cells with HMC3 (microglial) cells promoted M2-polarization of HMC3 and the secretion of pro-GBM cytokines TGF-β and IL-6. Results Comparative qPCR analysis of TMZ-S and TMZ-R cells showed that a significantly higher level of SNHG15, coincidental with a higher level of Sox2, β-catenin, EGFR, and CDK6 in TMZ-R cells. Subsequently, using bioinformatics tool, a potential mechanistic route for SNHG15 to promote GBM tumorigenesis was by inhibiting tumor suppressor, miR-627-5p which leads to activation of CDK6. Gene-silencing technique was employed to demonstrate that suppression of SNHG15 indeed led to the suppression of GBM tumorigenesis, accompanied by an increase miR-627-5p and decreased its two oncogenic targets, CDK6 and SOX-2. In addition, SNHG15-silenced TMZ-R cells became significantly sensitive towards TMZ treatment and less capable of promoting M2-phenotype in the HMC3 microglial cells. We then evaluated the potential anti-GBM activity of CDK6 inhibitor, palbociclib, using TMZ-R PDX mouse models. Palbociclib treatment significantly reduced tumorigenesis in TMZ-R/HMC3 bearing mice and SNHG15 and CDK6 expression was significantly reduced while miR-627-5p level was increased. Additionally, palbociclib treatment appeared to overcome TMZ resistance as well as reduced M2 markers in HMC3 cells. Conclusion Together, we provided evidence supporting the usage of CDK6 inhibitor for TMZ-resistant GBM cases. Further investigation is warranted for the consideration of clinical trials. Graphical abstract Electronic supplementary material The online version of this article (10.1186/s13046-019-1371-0) contains supplementary material, which is available to authorized users.

Tin‐based compounds have received much attention as anode materials for lithium/sodium ion batteries owing to their high theoretical capacity. However, the huge volume change usually leads to the pulverization of electrode, giving rise to a poor cycle performance, which have severely hampered their practical application. Herein, highly durable yolk–shell SnSe2 nanospheres (SnSe2@SeC) are prepared by a multistep templating method, with an in situ gas‐phase selenization of the SnO2@C hollow nanospheres. During this process, Se can be doped into the carbon shell with a tunable amount and form SeC bonds. Density functional theory calculation results reveal that the SeC bonding can enhance the charge transfer properties as well as the binding interaction between the SnSe2 core and the carbon shell, favoring an improved rate performance and a superior cyclability. As expected, the sample delivers reversible capacities of 441 and 406 mAh g−1 after 2000 cycles at 2 and 5 A g−1, respectively, as the anode material for a sodium‐ion battery. Such performances are significantly better than the control sample without the SeC bonding and also other metal selenide‐based anodes, evidently showing the advantage of Se doping in the carbon shell.

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Because of its high theoretical capacity, MnSe has been identified as a promising candidate as the anode material for sodiumion batteries. However, its fast capacity deterioration due to the huge volume change during the intercalation/deintercalation of sodium ions severely hinders its practical application. Moreover, the sodium storage mechanism of MnSe is still under discussion and requires in-depth investigations. Herein, the unique thorn ball-like α-MnSe/C nanospheres have been prepared using manganese-containing metal organic framework (Mn-MOF) as a precursor followed by in situ gas-phase selenization at an elevated temperature. When serving as the anode material for sodium-ion battery, the as-prepared α-MnSe/C exhibits enhanced sodium storage capabilities of 416 and 405 mAh g −1 at 0.2 and 0.5 A g −1 after 100 cycles, respectively. It also shows a superior capacity retention of 275 mA h g −1 at 10 A g −1 after 2000 cycles, and a rate performance of 279 mA h g −1 at 20 A g −1 . Such sodium storage properties could be attributed to the unique structure offering a highly efficient Na + diffusion kinetics with a diffusion coefficient between 1 × 10 -11 and 3 × 10 -10 cm 2 s −1 . The density functional theory calculation indicates that the fast Na + diffusion mainly takes place on the (100) plane of MnSe along a V-shaped path because of a relatively low diffusion energy barrier of 0.15 eV.

The output power efficiency of the fuel cell system mainly depends on the required current, stack temperature, air excess ratio, hydrogen excess ratio, and inlet air humidity. Therefore, the operating conditions should be optimized to get maximum output power efficiency. In this paper, a dynamic model for the fuel cell stack was developed, which is comprised of a mass flow model, a gas diffusion layer model, a membrane hydration, and a stack voltage model. Experiments have been performed to calibrate the dynamic Polymer Electrolyte Membrane Fuel Cell (PEMFC) stack model. To achieve the maximum output power and the minimum use of hydrogen in a certain power condition, optimization was carried out using Response Surface Methodology (RSM) based on the proposed PEMFC stack model. Using the developed method, optimal operating conditions can be effectively selected in order to obtain minimum hydrogen consumption.

Composite materials are increasingly used in wind blade because of their superior mechanical properties such as high strength-to-weight and stiffness-to-weight ratio. This paper presents vibration and damping analysis of fiberreinforced composite wind turbine blade with viscoelastic damping treatment. The finite element method based on full layerwise displacement theory was employed to analyze the damping, natural frequency, and modal loss factor of composite shell structure. The lamination angle was considered in mathematical modeling. The curved geometry, transverse shear, and normal strains were exactly considered in present layerwise shell model, which can depict the zig-zag in-plane and out-of-plane displacements. The frequency response functions of curved composite shell structure and wind blade were calculated. The results show that the damping ratio of viscoelastic layer is found to be very sensitive to determination of magnitude of composite structures. The frequency response functions with variety of thickness of damping layer were investigated. Moreover, the natural frequency, modal loss factor, and mode shapes of composite fiber reinforced wind blade with viscoelastic damping control were calculated.