High resolution and large measurement range voltage sensing based on an optoelectronic oscillator utilizing an unbalanced Mach-Zehnder interferometer.

A voltage sensor with high resolution and large measurement range based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The key component in the cavity to select the oscillating signal is a finite impulse response (FIR)-microwave photonic filter (MPF) which consists of a sinusoidal broadband optical signal, an unbalanced Mach-Zehnder interferometer (MZI), a section of dispersion compensating fiber, and a photodetector. The center frequency of the FIR-MPF is mainly determined by the free spectral range (FSR) of the FIR-MPF. In the lower arm of the MZI, a cylindrical piezoelectric ceramic (PZT) wrapped with a section of optical fiber acts as voltage sensing head. Due to the inverse piezoelectric effect of PZT, the variation of the voltage will cause radial deformation of the cylindrical PZT and then lead to the change of the FSR of the MZI, determining the shift of center frequency of FIR-MPF as well as the frequency of the oscillating signal of the OEO. Thus, by monitoring the shift of the oscillation frequency of the OEO using an electric spectrum analyzer or a digital signal processor, a high-speed interrogation and high-resolution voltage measurement can be realized. Additionally, in the proposed scheme, an infinite impulse response (IIR)-MPF consisting of a fiber ring resonator is cascaded with the FIR-MPF to ensure the single-mode oscillation of the OEO. The experimental results show that a total range of 1700 V voltage sensing from - 200 V to 1500 V is accomplished with the voltage sensitivity of 0.25 GHz/100 V and the resolution of 0.3 V. By adjusting the proportion of the length of single mode fiber between two branches of MZI, the impact of temperature can be greatly reduced. The proposed sensor offers advantages such as a large measurement range, high resolution, high-speed interrogation, and stability to temperature disturbances, making it highly suitable for sensing applications in smart grids.

Simultaneous magnetic field and temperature measurement with high resolution based on cascaded microwave photonic filters.

A simultaneous magnetic field and temperature sensing scheme based on cascaded microwave photonic filters (MPFs) with high resolution is proposed and experimentally demonstrated. A polarization maintaining fiber bonded with a giant magnetostrictive material acts both as a magnetic field sensing probe and an important unit of a dispersion-induced MPF. A 500 m single mode fiber in a two-tap MPF is used to perform temperature compensation. The power fading frequency of the dispersion-induced MPF and the dip frequency of the two-tap MPF are selected to monitor the magnetic field and temperature changes. When temperature changes, both power fading frequency and dip frequency will change. While only power fading frequency shifts as magnetic field changes. Consequently, dual parameter sensing can be achieved by monitoring the characteristic microwave frequencies of the two MPFs. The temperature cross-sensitivity is well resolved in this way. In the experiment, the microwave frequency changes 5.84 MHz as external magnetic field increases by 1 mT. The corresponded theoretical resolution can reach 0.17 nT, which is only limited by the minimum resolution of vector network analyzer.

Alternative Splicing for Leucanthemella linearis NST1 Contributes to Variable Abiotic Stress Resistance in Transgenic Tobacco.

Leucanthemella linearis is a marsh plant in the family Compositae. It has good water and moisture resistance and ornamental properties, which makes it one of the important materials for chrysanthemum breeding and genetic improvement. The NST1 (NAC secondary wall enhancement factor 1) gene is associated with the thickening of the secondary walls of fiber cells in the plant ducts and the secondary xylem and plays an important role in plant stress resistance. In this study, two variable spliceosomes of the NST1 gene were identified from a chrysanthemum plant by using bioinformatics, qRT-PCR, transgene, and paraffin section methods to explore the molecular mechanism of the variable splicing of NST1 under abiotic stress. The results show that only three amino acids were found to be different between the two LlNST1 variants. After being treated with salt, drought, and low temperatures, analysis of the expression levels of the LlNST1 and LlNST1.1 genes in Ll showed that LlNST1.1 could respond to low temperatures and salt stress and had a weak response to drought stress. However, the expression level of LlNST1 under the three treatments was lower than that of LlNST1.1. LlNST1 transgenic tobacco showed increased saline-alkali resistance and low-temperature resistance at the seedling stage. LlNST1.1 transgenic tobacco also showed enhanced saline-alkali resistance and drought resistance at the seedling stage. In conclusion, the functions of the two variable spliceosomes of the NST1 gene are very different under abiotic stress. Therefore, this study verified the function of the variable spliceosome of NST1 and improved the stress resistance of the chrysanthemum plant under examination by regulating the expression of the NST protein, which lays a material foundation for the improvement of plant stress resistance materials and has important significance for the study of the resistance of chrysanthemum plants to abiotic stress.

Simultaneous modulation format identification and OSNR monitoring based on optoelectronic reservoir computing.

An approach for simultaneous modulation format identification (MFI) and optical signal-to-noise ratio (OSNR) monitoring in digital coherent optical communications is proposed based on optoelectronic reservoir computing (RC) and the signal's amplitude histograms (AHs) obtained after the adaptive post-equalization. The optoelectronic RC is implemented using a Mach-Zehnder modulator and optoelectronic delay feedback loop. We investigate the performance of the proposed model with the number of symbols, bins of AHs and the hyperparameters of optoelectronic RC. The results show that 100% MFI accuracy can be achieved simultaneously with accurate OSNR estimation for different modulation formats under study. The lowest achievable OSNR estimation mean absolute errors for the dual-polarization (DP)-quadrature phase-shift keying signal, the DP-16-ary quadrature amplitude modulation (16QAM) signal, and the DP-64QAM signal are 0.2 dB, 0.32 dB and 0.53 dB, respectively. The robustness of the proposed scheme is also evaluated when the optoelectronic RC is in presence of additive white Gaussian noises. Then, a proof of concept experiment is demonstrated to further verify our proposed method. The proposed approach offers a potential solution for next-generation intelligent optical performance monitoring in the physical layer.

Enhanced performance of a reservoir computing system based on a dual-loop optoelectronic oscillator.

Time-delayed reservoir computing (RC) is a brain inspired paradigm for processing temporal information, with simplification in the network's architecture using virtual nodes embedded in a temporal delay line. In this work, a novel, to the best of our knowledge, RC system based on a dual-loop optoelectronic oscillator is proposed to enhance the prediction and classification. The hardware is compact and easy to implement, and only a section of fiber compared to the traditional optoelectronic oscillator reservoir is added to conform the dual-loop scheme. Compared with the traditional reservoir, a remarkable performance of the proposed RC system is demonstrated by simulation on three well-known tasks, namely the nonlinear auto regressive moving average (NARMA10) task, signal waveform recognized task, and handwritten numeral recognition. The parameter optimization in the NARMA10 task is presented with influenced factors. The novel RC system finally obtains a normalized mean square error at 0.0493±0.007 in NARMA10 task, 6.172×10-6 in signal waveform recognized task, and a word error rate at 9% in handwritten numeral recognition with suitable parameters.

Sorafenib attenuates liver fibrosis by triggering hepatic stellate cell ferroptosis via HIF-1α/SLC7A11 pathway.

OBJECTIVES: Evidences demonstrate that sorafenib alleviates liver fibrosis via inhibiting HSC activation and ECM accumulation. The underlying mechanism remains unclear. Ferroptosis, a novel programmed cell death, regulates diverse physiological/pathological processes. In this study, we aim to investigate the functional role of HSC ferroptosis in the anti-fibrotic effect of sorafenib. MATERIALS AND METHODS: The effects of sorafenib on HSC ferroptosis and ECM expression were assessed in mouse model of liver fibrosis induced by CCl4 . In vitro, Fer-1 and DFO were used to block ferroptosis and then explored the anti-fibrotic effect of sorafenib by detecting α-SMA, COL1α1 and fibronectin proteins. Finally, HIF-1α siRNA, plasmid and stabilizers were applied to assess related signalling pathway. RESULTS: Sorafenib attenuated liver injury and ECM accumulation in CCl4 -induced fibrotic livers, accompanied by reduction of SLC7A11 and GPX4 proteins. In sorafenib-treated HSC-T6 cells, ferroptotic events (depletion of SLC7A11, GPX4 and GSH; accumulation iron, ROS and MDA) were discovered. Intriguingly, these ferroptotic events were not appeared in hepatocytes or macrophages. Sorafenib-elicited HSC ferroptosis and ECM reduction were abrogated by Fer-1 and DFO. Additionally, both HIF-1α and SLC7A11 proteins were reduced in sorafenib-treated HSC-T6 cells. SLC7A11 was positively regulated by HIF-1α, inactivation of HIF-1α/SLC7A11 pathway was required for sorafenib-induced HSC ferroptosis, and elevation of HIF-1α could inhibit ferroptosis, ultimately limited the anti-fibrotic effect. CONCLUSIONS: Sorafenib triggers HSC ferroptosis via HIF-1α/SLC7A11 signalling, which in turn attenuates liver injury and fibrosis.

Carvacrol alleviates liver fibrosis by inhibiting TRPM7 and modulating the MAPK signaling pathway.

Liver fibrosis is a compensatory response to the tissue repair process. The activation and proliferation of hepatic stellate cells (HSCs) are thought to be related to the occurrence of hepatic fibrosis. Therefore, inhibiting the activation and proliferation of HSCs is a key step in alleviating liver fibrosis. As a non-specific inhibitor of transient receptor potential melastatin 7 (TRPM7), carvacrol has anti-tumor, anti-inflammatory and anti-hepatic fibrosis activities. This study aimed to explore the protective effect of carvacrol on liver fibrosis and related molecular mechanisms. A CCl4-induced liver fibrosis mouse model and platelet-derived growth factor (PDGF-BB)-activated HSC-T6 cells (a rat hepatic stellate cell line) were employed for in vivo and in vitro experiments. C57BL/6J mice were orally administered different concentrations of carvacrol every day for 6 weeks during the development of CCl4-induced liver fibrosis. The results show that carvacrol could effectively reduce liver damage and the progression of liver fibrosis in mice, which are expressed as fibrotic markers levels were reduced and histopathological characteristics were improved. Moreover, carvacrol inhibited the proliferation and activation of HSC-T6 cells induced by PDGF-BB. In addition, it was found that carvacrol inhibits the expression of TRPM7 and mediated through mitogen-activated protein kinases (MAPK). Collectively, our study shows that carvacrol can reduce liver fibrosis by inhibiting the activation and proliferation of hepatic stellate cells, and the MAPK signaling pathway might be involved in this process.

PD-1/PD-L1 enhanced cisplatin resistance in gastric cancer through PI3K/AKT mediated P-gp expression.

BACKGROUND: Programmed cell death receptor 1 (PD-1) is an immunosuppressive molecule expressed on T cells, and its ligand (PD-L1) which expressed on tumor cells play pivotal roles in regulating host immune responses. However, little is known whether PD-1/PD-L1 axis could directly activates intracellular oncogenic signaling pathways in tumor cells, leading to tumor resistance. METHODS: In the present study, the expression of PD-1 and PD-L1 in the tissues of gastric cancer was detected by western blot and immunofluorescence. The effect of PD-L1-Fc and cisplatin on resistant gastric cancer cells was examined by MTT assay and Flow Cytometry. In addition. The effect of PD-L1-Fc on the expression of P-gp in gastric cancer cells and resistant gastric cancer cells was detected by quantitative real-time reverse-transcription PCR (qRT-PCR) and western blot. The molecular mechanisms of the regulation of cisplatin and PD-L1-Fc treatment were evaluated by western blot. RESULTS: We found that the level of PD-1 was significantly increased in human gastric cancer tissues and drug-resistant gastric cancer cells and P-gp was the same result. The PD-L1 could reduce the level of cell damage caused by cisplatin. In addition, we found PD-L1 can also up-regulate the expression of P-gp. Mechanistically, PD-L1 activated the PI3K/AKT signaling pathway in which PI3K/AKT pathway inhibition attenuated the upregulation of P-gp. CONCLUSION: PD-1/PD-L1 enhanced cisplatin resistance in gastric cancer through PI3K/AKT mediated P-gp expression.

TRPM7 modulates macrophage polarization by STAT1/STAT6 pathways in RAW264.7 cells.

Macrophages, diversity and plasticity immune cells, participate in immune response and maintain homeostasis through M1/M2 phenotype transformation. Transient receptor potential melastatin 7 (TRPM7) is a widely expressed divalent cation channel with protein serine/threonine kinase activity, which has recently been found to affect macrophage proliferation and function. This study aimed to identify the role of TRPM7 in macrophage polarization. Our results suggested that TRPM7 was highly expressed in M1-type macrophages rather than M2-type macrophages. Interestingly, we detected that M1-type macrophages decreased while M2-type macrophages enhanced through blockade of TRPM7, which manifest as decreased TNF-α, iNOS and elevated Arg-1, CD206. Furthermore, blockade of TRPM7 could inhibit STAT1 phosphorylation and promote STAT6 phosphorylation. In conclusion, TRPM7 could regulate macrophage polarization via STAT1/STAT6 pathways. Taken together, it is suggested that TRPM7 might serve as a molecular regulator in macrophage polarization and is a potential therapeutic target for inflammatory diseases.

Graphene quantum dots to enhance the photocatalytic hydrogen evolution efficiency of anatase TiO2 with exposed {001} facet.

Hydrogen evolution through photocatalysis is promising with respect to the environmental problems and challenges of energy shortage that we encounter today. In this paper, we have combined graphene quantum dots (GQDs) and {001} faceted anatase TiO2 (with an exposed percentage of 65-75%) together for effective photocatalytic hydrogen evolution. A series of characterizations including X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and UV-visible absorption spectroscopy have been carried out to study the structure of the as-prepared GQDs/{001}TiO2 composite. It turns out that GQDs could be effectively decorated on {001}TiO2 sheet without changing its intrinsic structure. With an optimum loading amount of GQDs (0.5 wt% to {001}TiO2), GQDs/{001}TiO2 exhibits a hydrogen evolution efficiency 8 times higher than that of bare {001}TiO2, which is a significantly more obvious improvement than many other photocatalytic systems relevant to GQDs and TiO2 hybrids. In addition, GQDs/{001}TiO2 could stand long-term photocatalytic experiments. Photocurrent tests show that such an improvement of the photocatalytic efficiency over GQDs/{001}TiO2 may originate from a higher charge separation efficiency. The present study could offer reference for the construction of photocatalytic hydrogen evolution systems with low cost and long term stability.

[Effects and mechanisms of punicosides on acute alcoholic liver damage in mice].

OBJECTIVE: To evaluate the protective effects of punicosides on alcohol induced acute liver injury in mice and its possible mechanisms as well. METHOD: The 60 mice were randomly divided into normal control, model group, three dose groups of punicosides with low, medium and high, then there is silibinin group. Three dose groups of punicosides and silibinin were given in advance by gavage for 4 weeks, then the mouse model of alcoholic acute liver injury was established. The serum levels of ALT, AST and TG were determined, and the mice were killed to calculate somatic index of liver, thymus as well as spleen. MDA, SOD, GSH-Px and GSH-ST were detected in the liver homogenate. Histopathological changes of the liver were observed by HE staining. The expression of MCP-1 and NF-kappaB in the liver tissues were detected by immunohistochemistry. RESULT: Mid and high dose of punicosides reduced the liver index in mice significantly, improved liver steatosis, decreased the level of ALT, AST and TG in serum and the content of MDA in liver homogenate, furthermore the two dose groups increased the activity of SOD, GSH-Px and GSH-ST, inhibited the expression of MCP-1 and NF-kappaB in liver tissue. CONCLUSION: Punicosides can protect the acute liver damage induced by alcohol.