Repetitive hot deformation has been demonstrated as a new approach to obtain high-performance n-type bismuth–telluride-based alloys, benefiting from the deformation-induced lattice defects and ...texture enhancement. X-ray diffraction measurement showed that the oriented textures were greatly enhanced after repetitive hot deformation of the alloys with a quasi-layered crystal structure. The electrical conductivity was remarkably improved by the deformation-induced donor-like defect and texture enhancement, while the Seebeck coefficient remained almost unchanged, and consequently the room temperature power factor was significantly increased from 1.3Wm−1K2, before hot deformation, to 2.9Wm−1K2 after four hot deformations. The in-plane lattice thermal conductivity was also largely reduced by the generated high-density lattice defects during the hot-deformation process. The maximum ZT value for the repetitively hot-deformed samples reached 1.0 at 513K, suggesting that the simple new top-down method is very promising for large-scale production of high-performance bismuth–telluride-based polycrystalline bulk materials.
Abstract
At the interface between monolayer FeSe films and SrTiO
3
substrates the superconducting transition temperature (
T
c
) is unexpectedly high, triggering a surge of excitement. The mechanism ...for the
T
c
enhancement has been the central question, as it may present a new strategy for seeking out higher
T
c
materials. To reveal this enigmatic mechanism, by combining advances in high quality interface growth,
16
O
$$\leftrightarrow$$
↔
18
O isotope substitution, and extensive data from angle resolved photoemission spectroscopy, we provide striking evidence that the high
T
c
in FeSe/SrTiO
3
is the cooperative effect of the intrinsic pairing mechanism in the FeSe and interactions between the FeSe electrons and SrTiO
3
phonons. Furthermore, our results point to the promising prospect that similar cooperation between different Cooper pairing channels may be a general framework to understand and design high-temperature superconductors.
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus known to cause epidemics resulting in predominantly symptomatic infections, which in rare cases cause long term debilitating arthritis and ...arthralgia. Significant progress has been made in understanding the roles of canonical RNA sensing pathways in the host recognition of CHIKV; however, less is known regarding antagonism of CHIKV by cytosolic DNA sensing pathways like that of cyclic GMP-AMP synthase (cGAS) and Stimulator of Interferon Genes (STING). With the use of cGAS or STING null cells we demonstrate that the pathway restricts CHIKV replication in fibroblasts and immune cells. We show that DNA accumulates in the cytoplasm of infected cells and that CHIKV blocks DNA dependent IFN-β transcription. This antagonism of DNA sensing is via an early autophagy-mediated degradation of cGAS and expression of the CHIKV capsid protein is sufficient to induce cGAS degradation. Furthermore, we identify an interaction of CHIKV nsP1 with STING and map the interaction to 23 residues in the cytosolic loop of the adaptor protein. This interaction stabilizes the viral protein and increases the level of palmitoylated nsP1 in cells. Together, this work supports previous publications highlighting the relevance of the cGAS-STING pathway in the early detection of (+)ssRNA viruses and provides direct evidence that CHIKV interacts with and antagonizes cGAS-STING signaling.
This paper investigates the probability density evolution process of a van der Pol-Duffing oscillator under Gaussian white noise. A path integration method is employed with the Gauss–Legendre ...integration scheme. In the path integration method, the short-time Gaussian approximation scheme is used for computing the one-step transition probability density. Two cases are considered with slight nonlinearity or strong nonlinearity in displacement. The stationary and non-stationary responses of the oscillator are studied. Compared with the simulation result, the path integration method can present a satisfactory probability density function (PDF) solution for each case. Different probability density evolution processes are observed correspondingly. In the case of slight nonlinearity, the PDF undergoes a clockwise motion around the origin. The peak region gradually expands and the PDF eventually forms a circle. By contrast, the strong nonlinearity drives the oscillator to oscillate around the limit cycle. In such a case, the PDF rapidly forms a circle. The circle keeps its shape and develops until the oscillator becomes stationary. More complicated phenomena can be studied by the adopted path integration method.
Previous studies have established the link between aberrant microRNA (miRNA) expression and hypoxia in various neoplasms. However, how these hypoxia-related miRNAs modulate tumor progression is still ...unclear. Therefore, the patterns of miRNA in colorectal carcinoma cell lines in response to hypoxia or not were first screened and the hypoxia-induced repression of the miR-15-16 cluster was confirmed. Then, this repression was found to be associated with high tumor stage and poor prognosis in colorectal carcinoma and is shown to promote tumor angiogenesis and metastasis by the loss of restriction of its target gene, fibroblast growth factor-2 (FGF2). Moreover, the general and alterative promoters of the miR-15-16 host (deleted in lymphocytic leukemia 2, DLEU2) were mapped, and three c-Myc/Max binding sites in response to the hypoxia-induced repression of miR-15-16 were further identified. Finally, an enhanced stability of c-Myc/Max heterodimer promoted by increased hypoxia-inducible factor-2α (HIF-2α) was validated, and we also verified that the enhancement contributed to the hypoxia-induced repression of miR-15-16. In brief, the c-Myc-mediated transcriptional repression of miR-15-16 in hypoxia is induced by increased HIF-2α and promoted tumor angiogenesis and hematogenous metastasis by the further loss of post-transcriptional inhibition of FGF2. Our study provides a better understanding of the coping mechanisms in response to tumor hypoxia and may be helpful in developing an effective prognostic marker or treatment target against solid tumors.
An accurate, simple, and practical numerical method for exact calculation of harmonics/interharmonics using adaptive window width is presented in this paper. The proposed method adaptively adjusts ...the window width based on correlation calculation, thus completely eliminating or significantly reducing the unacceptable spectral leakage errors in the frequency domain caused by truncation of the time-domain signal. The iterative algorithm does not require any knowledge about the system frequency and the interharmonic constituents; the only parameter needed is the signal sequence obtained by sampling the analog signal at equidistant sampling interval. Various case studies using simulation data, experimental data and the real world data show that the adaptive algorithm provides an ideal numerical solution to the problem of spectral leakage encountered in harmonics and interharmonics detection and analysis.
COX-2 is a major regulator in colorectal inflammation and cancer. Herein, we first report that primary cancer-associated colonic fibroblasts activated by HGF play a critical role in mediation of ...proliferation and invasiveness of human colonic epithelial cancer cells. We have discovered that the proliferation and invasiveness of colonic epithelial cancer cells are predominantly enhanced through activation of PKC-cMET-ERK1/2-COX-2 signaling by HGF in the co-cultured cancer-associated fibroblasts. This conclusion is supported by the fact, that a selective PKC inhibitor, BIM, inhibits ERK1/2 and COX-2 signalings, MEK/ERK1/2 inhibitor, PD98059, nullifies COX-2 signaling, and COX-2 inhibitor, NS-398, attenuates the proliferation and invasiveness potential of the colonic cancer cells. We have concluded that HCF-activated cancer associated fibroblasts play a critical role in carcinogenesis of colonic cancer.
•Colonic fibroblasts interact with colonic epithelia.•Colonic fibroblasts activated by HGF medicate proliferation of colonic cancer cells.•Colonic fibroblasts activated by HGF medicate invasiveness of colonic cancer cells.•The mediation is via PKC-cMET-ERK1/2-COX-2 signaling in the fibroblasts.
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