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In view of problems of low positioning accuracy of underground personnel positioning system and incomplete functions of underground personnel vital signs monitoring system, a wearable device with functions of personnel positioning, falling or lying posture monitoring and heart rate monitoring was studied. The device adopts combination of RSSI ranging and step calculation to improve positioning accuracy of underground personnel. Three-axis acceleration sensor is used to detect abnormal movement of person, and heart rate sensor is used to obtain heart rate data. The test results show that the device can achieve accurate positioning of underground personnel, can accurately determine falling or lying posture of underground personnel, and alarm abnormal state.

Chronic elevated free fatty (FFA) levels are linked to metabolic disorders and tumorigenesis. However, the molecular mechanism by which FFAs induce cancer remains poorly understood. Here, we show that the tumor suppressor PTEN protein levels were decreased in high fat diet (HFD) fed mice. As palmitic acid (PA, C16:0) showed a significant increase in the HFD fed mice, we further investigated its role in PTEN down regulation. Our studies revealed that exposure of cells to high doses of PA induced mTOR/S6K-mediated phosphorylation of PTEN at T366. The phosphorylation subsequently enhanced the interaction of PTEN with the E3 ubiquitin ligase WW domain-containing protein 2 (WWP2), which promoted polyubiquitination of PTEN and protein degradation. Consistent with PTEN degradation, exposure of cells to increased concentrations of PA also promoted PTEN-mediated AKT activation and cell proliferation. Significantly, a higher level of S6K activation, PTEN T366 phosphorylation, and AKT activation were also observed in the livers of the HFD fed mice. These results provide a molecular mechanism by which a HFD and elevated PA regulate cell proliferation through inactivation of tumor suppressor PTEN.

A novel peroxidase-like nanozyme has been constructed by decorating two-dimensional Ti3C2Tx nanosheets (Ti3C2Tx NSs) with gold nanoparticles (AuNPs) to develop a colorimetric and photothermal dual-mode immunosensor. The Ti3C2Tx/AuNPs nanocomposite-catalyzed 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 reaction system produces the one-electron oxidation product of TMB (oxTMB), which exhibits color change and strong near-infrared (NIR) laser-driven photothermal effect at 808 nm laser irradiation. Given these characteristics, the developed immunosensor achieves ultrasensitive dual-mode detection of zearalenone (ZEN) by measuring colorimetric and photothermal signals with a microplate reader and a portable infrared thermometer, respectively. Under optimal working conditions, the limit of detection (LOD) of ZEN is 0.15 pg mL−1 for the colorimetric mode and 0.48 pg mL−1 for the photothermal mode. In the analysis of actual contaminated cereals samples, the test result of this method was consistent with that of UPLC-MS/MS. The proposed colorimetric and photothermal dual-mode immunosensor offers a new strategy for the low-cost detection of hazardous substances. The application of a widely used household infrared thermometer makes the signal readout more convenient, which provides great prospects in food safety and environment inspection applications. [ABSTRACT FROM AUTHOR]

A van der Waals intrinsic ferromagnet with double magnetic atom layers is of great interest for both revealing fundamental physics and exploring promising applications in low-dimensional spintronics. Here, the magnetic and electronic properties of the van der Waals ferromagnet MgV2S4 monolayer are studied under electrostatic doping using first-principles calculations. A MgV2S4 monolayer presents the desired physical properties such as that of being a half-semiconductor with a direct bandgap of 1.21 eV and a ferromagnetic ground state, and having a high Curie temperature of 462 K. Unlike the robust ferromagnetic ground state, magnetic anisotropy and Curie temperature are sensitive to electrostatic doping. Meanwhile, the transition from a semiconductor to a half-metal and the significant improvement in conductivity under electrostatic doping make the MgV2S4 monolayer a promising candidate for low-dimensional spintronic field-effect transistors. [ABSTRACT FROM AUTHOR]

The van der Waals spin valve, usually consisting of two ferromagnetic layers separated by a nonmagnetic layer, is potentially useful for low-dimensional spintronic devices. Can the spin valve effect be realized in a monolayer van der Waals material? Motivated by the recent synthesis of the MoSi2N4 monolayer and WSi2N4 monolayer, we investigate the spin valve effect in the TiCr2N4 monolayer based on density functional theory and Boltzmann transport theory. The TiCr2N4 monolayer retains a ferromagnetic ground state above room temperature, whose electrical transport property is strongly dependent on the angle of magnetization direction between the two Cr atomic layers. As the angle increases, the conductivity reduces dramatically and results in giant magnetoresistance in the TiCr2N4 monolayer. The serious reduction of conductivity originates from the enlargement of the band gaps, which results in appreciable reduction of the electron group velocity and carriers near the Fermi level. The large difference in conductivity between the TiCr2N4 monolayers with parallel and anti-parallel magnetization makes it an ideal candidate for spin valve devices. Our results reveal the potential opportunities of a ferromagnet with monolayer limitations for spintronics and a unique platform for exploring fundamental physics. [ABSTRACT FROM AUTHOR]