Enhancing regulatory T-cell function via inhibition of high mobility group box 1 protein signaling in immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is the most common acquired autoimmune bleeding disorder. Abnormally increased levels of High Mobility Group Box 1 (HMGB1) protein associate with thrombocytopenia and therapeutic outcome in ITP. Previous studies proposed that a natural inhibitor of HMGB1, 18β-glycyrrhetinic acid (18β-GA), could be used for its anti-inflammatory and immune-modulatory effects, although its ability to correct immune balance in ITP is unclear. In this study, we showed that plasma HMGB1 correlated negatively with platelet counts in ITP patients, and confirmed that 18β-GA stimulated the production of regulatory T cells (Treg), restored the balance of CD4+ T-cell subsets and enhanced the suppressive function of Treg through blocking the effect on HMGB1 in patients with ITP. HMGB1 short hairpin RNA interference masked the effect of 18β-GA in Treg of ITP patients. Furthermore, we found that 18β-GA alleviated thrombocytopenia in mice with ITP. Briefly, anti-CD61 immune-sensitized splenocytes were transferred into severe combined immunodeficient mice to induce a murine model of severe ITP. The proportion of circulating Treg increased significantly, while the level of plasma HMGB1 and serum antiplatelet antibodies decreased significantly in ITP mice along 18β-GA treatment. In addition, 18β-GA reduced phagocytic activity of macrophages towards platelets both in ITP patients and ITP mice. These results indicate that 18β-GA has the potential to restore immune balance in ITP via inhibition of HMGB1 signaling. In short, this study reveals the role of HMGB1 in ITP, which may serve as a potential target for thrombocytopenia therapy

A Novel Desert Vegetation Extraction and Shadow Separation Method Based on Visible Light Images from Unmanned Aerial Vehicles

Owing to factors such as climate change and human activities, ecological and environmental problems of land desertification have emerged in many regions around the world, among which the problem of land desertification in northwestern China is particularly serious. To grasp the trend of land desertification and the degree of natural vegetation degradation in northwest China is a basic prerequisite for managing the fragile ecological environment there. Visible light remote sensing images taken by a UAV can monitor the vegetation cover in desert areas on a large scale and with high time efficiency. However, as there are many low shrubs in desert areas, the shadows cast by them are darker, and the traditional RGB color-space-based vegetation index is affected by the shadow texture when extracting vegetation, so it is difficult to achieve high accuracy. For this reason, this paper proposes the Lab color-space-based vegetation index L2AVI (L-a-a vegetation index) to solve this problem. The EXG (excess green index), NGRDI (normalized green-red difference index), VDVI (visible band difference vegetation index), MGRVI (modified green-red vegetation index), and RGBVI (red-green-blue vegetation index) constructed based on RGB color space were used as control experiments in the three selected study areas. The results show that, although the extraction accuracies of the vegetation indices constructed based on RGB color space all reach more than 70%, these vegetation indices are all affected by the shadow texture to different degrees, and there are many problems of misdetection and omission. However, the accuracy of the L2AVI index can reach 99.20%, 99.73%, and 99.69%, respectively, avoiding the problem of omission due to vegetation shading and having a high extraction accuracy. Therefore, the L2AVI index can provide technical support and a decision basis for the protection and control of land desertification in northwest China

A Novel Desert Vegetation Extraction and Shadow Separation Method Based on Visible Light Images from Unmanned Aerial Vehicles

Owing to factors such as climate change and human activities, ecological and environmental problems of land desertification have emerged in many regions around the world, among which the problem of land desertification in northwestern China is particularly serious. To grasp the trend of land desertification and the degree of natural vegetation degradation in northwest China is a basic prerequisite for managing the fragile ecological environment there. Visible light remote sensing images taken by a UAV can monitor the vegetation cover in desert areas on a large scale and with high time efficiency. However, as there are many low shrubs in desert areas, the shadows cast by them are darker, and the traditional RGB color-space-based vegetation index is affected by the shadow texture when extracting vegetation, so it is difficult to achieve high accuracy. For this reason, this paper proposes the Lab color-space-based vegetation index L2AVI (L-a-a vegetation index) to solve this problem. The EXG (excess green index), NGRDI (normalized green-red difference index), VDVI (visible band difference vegetation index), MGRVI (modified green-red vegetation index), and RGBVI (red-green-blue vegetation index) constructed based on RGB color space were used as control experiments in the three selected study areas. The results show that, although the extraction accuracies of the vegetation indices constructed based on RGB color space all reach more than 70%, these vegetation indices are all affected by the shadow texture to different degrees, and there are many problems of misdetection and omission. However, the accuracy of the L2AVI index can reach 99.20%, 99.73%, and 99.69%, respectively, avoiding the problem of omission due to vegetation shading and having a high extraction accuracy. Therefore, the L2AVI index can provide technical support and a decision basis for the protection and control of land desertification in northwest China

Isothermal Oxidation TGO Growth Behaviors of Laser-Remolten LZO/YSZ Thermal Barrier Coatings

Laser scanning modification was applied to secondarily melt the top ceramic coating surface of lanthanum zirconate/yttria-stabilized zirconia double ceramic thermal barrier coatings (LZO/YSZ TBCs) to reduce the gas oxygen diffusion and improve the TBCs service life. Isothermal oxidations with different times were carried out on the as-sprayed (AS) TBCs and laser-remolten (LR) TBCs at 1100 °C to investigate thermally growth oxide (TGO)growth mechanisms and isothermal oxidation behaviors. The results showed that the laser-remolten top-ceramic-coating dense layer with a columnar crystal structure of LR TBCs presented a 96.3% and 59.1% lower surface roughness and porosity, respectively, than those of the top ceramic coating of AS TBCs, and the TGO growth rate of LR TBCs decreased by 46.2% compared to that of AS TBCs. The mixed-oxides appearance time of LR TBCs (50 h) was later than that of AS TBCs (25 h). After 100 h of isothermal oxidation, the total TGO thickness of LR TBCs was only 77.2% of that of AS TBCs, and the effects of the laser-remolten TBCs on gas oxygen diffusion inhibition and high-temperature oxidation resistance were promising in LZO/YSZ TBCs

Hydrostatin-SN1, a Sea Snake-Derived Bioactive Peptide, Reduces Inflammation in a Mouse Model of Acute Lung Injury

Snake venom has been used for centuries as a traditional Chinese medicine. Hydrostatin-SN1 (H-SN1), a bioactive peptide extracted from the Hydrophis cyanocinctus venom gland T7 phage display library, was reported to have the ability to reduce inflammation in a dextran sulfate sodium-induced murine colitis model. In this study, we sought to investigate the inhibitory potential of H-SN1 on inflammation in a murine model of lipopolysaccharide (LPS)-induced acute lung injury (ALI), and elucidate the anti-inflammatory mechanism in LPS-stimulated RAW 264.7 cells. In vivo, C57BL/6 male mice were intratracheally instilled with LPS or physiological saline with concurrent intraperitoneal injection of H-SN1 or saline alone. Lung histopathologic changes, lung wet-to-dry weight ratio, and myeloperoxidase activity in lung tissues were assessed. Total cell number, the protein concentration, and cytokine levels were determined in the bronchial alveolar lavage fluid. In vitro, RAW 264.7 cells were treated with various concentrations of H-SN1 for 2 h followed by incubation with or without 1 μg/ml LPS for 0.5 or 24 h. The mRNA expression of inflammatory cytokines was determined via RT-PCR and protein levels in the supernatants were measured via ELISA. Extracellular-signal related kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) pathways were analyzed via western blot. H-SN1 improved pulmonary edema status, decreased vascular permeability, suppressed pro-inflammatory cytokine production, and lessened lung morphological injury. H-SN1 also dose-dependently inhibited the mRNA expression and release of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW 264.7 cells. Moreover, H-SN1 inhibited the LPS-induced phosphorylation of ERK1/2 and the nuclear translocation of NF-κB. Our results suggest that H-SN1 could attenuate LPS-induced ALI in mice, which is associated with the anti-inflammatory effect of H-SN1. The mechanism might involve inhibiting the production of inflammatory cytokines by, at least in part, interfering with the ERK1/2 and NF-κB signaling pathways

Hydrostatin-SN1, a Sea Snake-Derived Bioactive Peptide, Reduces Inflammation in a Mouse Model of Acute Lung Injury

Snake venom has been used for centuries as a traditional Chinese medicine. Hydrostatin-SN1 (H-SN1), a bioactive peptide extracted from the Hydrophis cyanocinctus venom gland T7 phage display library, was reported to have the ability to reduce inflammation in a dextran sulfate sodium-induced murine colitis model. In this study, we sought to investigate the inhibitory potential of H-SN1 on inflammation in a murine model of lipopolysaccharide (LPS)-induced acute lung injury (ALI), and elucidate the anti-inflammatory mechanism in LPS-stimulated RAW 264.7 cells. In vivo, C57BL/6 male mice were intratracheally instilled with LPS or physiological saline with concurrent intraperitoneal injection of H-SN1 or saline alone. Lung histopathologic changes, lung wet-to-dry weight ratio, and myeloperoxidase activity in lung tissues were assessed. Total cell number, the protein concentration, and cytokine levels were determined in the bronchial alveolar lavage fluid. In vitro, RAW 264.7 cells were treated with various concentrations of H-SN1 for 2 h followed by incubation with or without 1 μg/ml LPS for 0.5 or 24 h. The mRNA expression of inflammatory cytokines was determined via RT-PCR and protein levels in the supernatants were measured via ELISA. Extracellular-signal related kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) pathways were analyzed via western blot. H-SN1 improved pulmonary edema status, decreased vascular permeability, suppressed pro-inflammatory cytokine production, and lessened lung morphological injury. H-SN1 also dose-dependently inhibited the mRNA expression and release of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW 264.7 cells. Moreover, H-SN1 inhibited the LPS-induced phosphorylation of ERK1/2 and the nuclear translocation of NF-κB. Our results suggest that H-SN1 could attenuate LPS-induced ALI in mice, which is associated with the anti-inflammatory effect of H-SN1. The mechanism might involve inhibiting the production of inflammatory cytokines by, at least in part, interfering with the ERK1/2 and NF-κB signaling pathways

Influence of the Three-Dimensional Effect of Pile-Soil System on the Vertical Dynamic Response of Large-Diameter Piles in Low-Strain Integrity Testing

The low-strain integrity testing of large-diameter piles has attracted more and more attention because of its wide application in offshore engineering, such as for wind turbines, etc. Body and Rayleigh waves generate on the top surface of large-diameter piles after the excitation load. The multi-reflections of these waves from the pile side result in the obvious three-dimensional effect at the pile top. Therefore, one-dimensional wave theory is no longer suitable for interpreting the wave propagation in the pile body under vertical excitation. In this paper, based on the “pile in pile” conception, both the pile and soil were simulated using a three-dimensional continuum model, considering the vertical displacement, to investigate the influence of the three-dimensional effect of the pile-soil system on the vertical dynamic response of large-diameter piles in low-strain integrity testing. The axisymmetric solution to the three-dimensional pile-soil system was obtained, and the rationality of the proposed solution was verified by comparing it with the results of the finite element method and the results of other existing solutions. Arithmetic examples were used to describe the influence of the three-dimensional effect of the pile-soil system on the vertical dynamic response of large-diameter piles