Heavy doping changes an intrinsic semiconductor into a metallic conductor by the introduction of impurity states. However, Ga impurities in thermoelectric skutterudite CoSb3 with lattice voids provides an example to the contrary. Because of dual‐site occupancy of the single Ga impurity charge‐compensated compound defects are formed. By combining first‐principle calculations and experiments, we show that Ga atoms occupy both the void and Sb sites in CoSb3 and couple with each other. The donated electrons from the void‐filling Ga (GaVF) saturate the dangling bonds from the Sb‐substitutional Ga (GaSb). The stabilization of Ga impurity as a compound defect extends the region of skutterudite phase stability toward Ga0.15Co4Sb11.95 whereas the solid–solution region in other directions of the ternary phase diagram is much smaller. A proposed ternary phase diagram for Ga‐Co‐Sb is given. This compensated defect complex leads to a nearly intrinsic semiconductor with heavy Ga doping in CoSb3 and a much reduced lattice thermal conductivity (κL) which can also be attributed to the effective scattering of both the low‐ and high‐frequency lattice phonons by the dual‐site occupant Ga impurities. Such a system maintains a low carrier concentration and therefore high thermopower, and the thermoelectric figure of merit quickly increases to 0.7 at a Ga doping content as low as 0.1 per Co4Sb12 and low carrier concentrations on the order of 1019 cm−3.
Background:Oral cancer metastasis is a devastating process that contributes to poor prognosis and high mortality, yet its detailed underlying mechanisms remain unclear. Here, we aimed to evaluate metastasis-specific markers in oral cancer and to provide comprehensive recognition concerning functional roles of the specific target in oral cancer metastasis.Methods:Lectin, galactoside-binding, soluble, 1 (LGALS1) was identified by secretomic analysis. LGALS1 expression of patient samples with oral cancer on the tissue microarray were examined by immunochemical (IHC) staining. Small interfering RNA (siRNA)-mediated knockdown of LGALS1 revealed the role of LGALS1 in oral cancer metastasis in vitro and in vivo.Results:LGALS1 was observed to be upregulated in highly invasive oral cancer cells, and elevated LGALS1 expression was correlated with cancer progression and lymph node metastasis in oral cancer tissue specimens. Functionally, silencing LGALS1 resulted in suppressed cell growth, wound healing, cell migration, and cell invasion in oral cancer cells in vitro. Knockdown of LGALS1 in highly invasive oral cancer cells dramatically inhibited lung metastasis in an in vivo mouse model. Mechanistic studies suggested p38 mitogen-activated protein kinase (MAPK) phosphorylation, upregulated MMP-9, and mesenchymal phenotypes of epithelial-mesenchymal transition (EMT) in highly invasive oral cancer cells, whereas siRNA against LGALS1 resulted in the inactivation of p38 MAPK pathway, downregulated MMP-9, and EMT inhibition.Conclusions:These findings demonstrate that elevated LGALS1 is strongly correlated with oral cancer progression and metastasis, and that it could potentially serve as a prognostic biomarker and an innovative target for oral cancer therapy.
Rapid advancements in information processing and embedded systems require high selective and fast sensors. Conventional gas sensors are not suitable for the detection of isomers of organic compounds due to cross-sensitivity and the response time being limited by slow chemical kinetics. Amperometric gas sensors using conducting polymers modified with metal catalysts are a suitable and robust system due to many tunable properties. In this paper, conducting polymer polyaniline was electrochemically decorated with clusters containing precisely defined number of gold atoms to function as an electro-catalyst. The modified polymer composite showed fast reaction rate for the electro-oxidation of alcohols in both liquid and gas phases. The number of gold atoms affected the catalytic activity. Cyclic voltammograms were measured and results showed discriminable patterns between n-propanol and isopropanol even at different gas concentrations. Thus, it was demonstrated that gas sensor arrays can be realized by decorating different number of gold atoms on polyaniline electrodes, to yield defined and different selectivity. Index Terms-Amperometric gas sensor, atomic gold, conducting polymer, electro-catalyst, polyaniline, propanol I. INTRODUCTIONGas sensors have a wide range of modern applications such as their use in breath analysis to detect anomaly in a patient's health, as security devices for monitoring gas leaks, quality control in the food industry etc. [1]. Conventional gas sensors, however, are known to face some common challenges such as cross-sensitivity to humidity [2] and amperometric gas sensors are electrochemical type of gas sensors that are a more robust choice due to their several merits [3] in terms of characteristics such as low power, ease of fabrication, and the ability to perform in humid conditions. Although such sensor characteristics are attractive, they come at a cost of slow
Ovarian cancer is the leading cause of death in patients diagnosed with gynaecologic carcinoma. The American Cancer Society reported approximately 22 530 cases of ovarian cancer and 13 980 cancer-related-deaths in 2019, indicating a relatively high fatality rate. In the case report, over 60% of patients died from ovarian cancer, compared to 15% of those with breast cancer. 1 This high
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