Background:Cancer-associated fibroblasts (CAFs) activated by tumour cells are the predominant type of stromal cells in breast cancer tissue. The reciprocal effect of CAFs on breast cancer cells and the underlying molecular mechanisms are not fully characterised.Methods:Stromal fibroblasts were isolated from invasive breast cancer tissues and the conditioned medium of cultured CAFs (CAF-CM) was collected to culture the breast cancer cell lines MCF-7, T47D and MDA-MB-231. Neutralising antibody and small-molecule inhibitor were used to block the transforming growth factor-β (TGF-β) signalling derived from CAF-CM, which effect on breast cancer cells.Results:The stromal fibroblasts isolated from breast cancer tissues showed CAF characteristics with high expression levels of α-smooth muscle actin and SDF1/CXCL12. The CAF-CM transformed breast cancer cell lines into more aggressive phenotypes, including enhanced cell–extracellular matrix adhesion, migration and invasion, and promoted epithelial–mesenchymal transition (EMT). Cancer-associated fibroblasts secreted more TGF-β1 than TGF-β2 and TGF-β3, and activated the TGF-β/Smad signalling pathway in breast cancer cells. The EMT phenotype of breast cancer cells induced by CAF-CM was reversed by blocking TGF-β1 signalling.Conclusion:Cancer-associated fibroblasts promoted aggressive phenotypes of breast cancer cells through EMT induced by paracrine TGF-β1. This might be a common mechanism for acquiring metastatic potential in breast cancer cells with different biological characteristics.
Two-color second-order correlations of the light scattered near-resonantly by a quantum dot were measured by means of spectrally-filtered coincidence detection. The effects of filter frequency and bandwidth were studied under monochromatic laser excitation, and a complete two-photon spectrum was reconstructed. The two-photon spectrum exhibits a rich structure associated with both real and virtual two-photon transitions down the "dressed states" ladder. Photon pairs generated via virtual transitions are found to violate the Cauchy-Schwarz inequality by a factor of 60. Our experiments are well described by the theoretical expressions obtained by del Valle et al. [PRL 109 183601 (2012)] via time-and normally-ordered correlation functions.
We present a simple method to reversibly
switch the adhesive force
between two surfaces that are decorated with poly(methyl methacrylate)
(PMMA) graft polymers. By employment of a PMMA/isopropanol/water or
a PMMA/ethanol/water cosolvent system, we can tune the swelling of
the brushes. In pure isopropanol or ethanol the polymer grafts are
collapsed, and the adhesion is high when the contacting brushes are
pulled apart. In an 80–20 vol % isopropanol–water or
ethanol–water composition, the brushes are swollen. In these
systems the adhesion is approximately 5 times smaller compared to
the adhesion measured in the pure solvent systems. Moreover, we show
that PMMA/isopropanol/water cosolvent systems perform better as switchable
adhesives than PMMA/ethanol/water cosolvent systems. In the latter
pulling events can arise when the swollen brushes are kept in contact
for a longer time, such that the adhesion hysteresis can become large
and the surface coating can be damaged due to bond-breaking events.
Understanding the melting behavior and the thermal equation of state of Fe‐Ni alloyed with candidate light elements at conditions of the Earth's core is critical for our knowledge of the region's thermal structure and chemical composition and the heat flow across the liquid outer core into the lowermost mantle. Here we studied the shock equation of state and melting curve of an Fe‐8 wt% Ni‐10 wt% Si alloy up to ~250 GPa by hypervelocity impacts with direct velocity and reliable temperature measurements. Our results show that the addition of 10 wt% Si to Fe‐8 wt% Ni alloy slightly depresses the melting temperature of iron by ~200–300 (±200) K at the core‐mantle boundary (~136 GPa) and by ~600–800 (±500) K at the inner core‐outer core boundary (~330 GPa), respectively. Our results indicate that Si has a relatively mild effect on the melting temperature of iron compared with S and O. Our thermodynamic modeling shows that Fe‐5 wt% Ni alloyed with 6 wt% Si and 2 wt% S (which has a density‐velocity profile that matches the outer core's seismic profile well) exhibits an adiabatic profile with temperatures of ~3900 K and ~5300 K at the top and bottom of the outer core, respectively. If Si is a major light element in the core, a geotherm modeled for the outer core indicates a thermal gradient of ~5.8–6.8 (±1.6) K/km in the D″ region and a high heat flow of ~13–19 TW across the core‐mantle boundary.
Earth’s outer core is liquid and dominantly composed of iron and nickel (~5–10 wt%). Its density, however, is ~8% lower than that of liquid iron, and requires the presence of a significant amount of light element(s). A good way to specify the light element(s) is a direct comparison of density and sound velocity measurements between seismological data and those of possible candidate compositions at the core conditions. We report the sound velocity measurements of a model core composition in the Fe-Ni-Si system at the outer core conditions by shock-wave experiments. Combining with the previous studies, we found that the best estimate for the outer core’s light elements is ~6 wt% Si, ~2 wt% S, and possible ~1–2.5 wt% O. This composition satisfies the requirements imposed by seismology, geochemistry, and some models of the early core formation. This finding may help us to further constrain the thermal structure of the Earth and the models of Earth’s core formation.
The sheer volume of scholarly publications available online significantly challenges how scholars retrieve the new information available and locate the candidate reference papers. While classical text retrieval and pseudo relevance feedback (PRF) algorithms can assist scholars in accessing needed publications, in this study, we propose an innovative publication ranking method with PRF by leveraging a number of meta-paths on the heterogeneous bibliographic graph. Different meta-paths on the graph address different ranking hypotheses, whereas the pseudo-relevant papers (from the retrieval results) are used as the seed nodes on the graph. Meanwhile, unlike prior studies, we propose "restricted meta-path" facilitated by a new context-rich heterogeneous network extracted from full-text publication content along with citation context. By using learning-to-rank, we integrate 18 different meta-path-based ranking features to derive the final ranking scores for candidate cited papers. Experimental results with ACM full-text corpus show that meta-path-based ranking with PRF on the new graph significantly (p < 0.0001) outperforms text retrieval algorithms with text-based or PageRank-based PRF.
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