Using remote sensing to rapidly acquire large-area crop growth information (e.g., shoot biomass, nitrogen status) is an urgent demand for modern crop production; unmanned aerial vehicle (UAV) acts as ...an effective monitoring platform. In order to improve the practicability and efficiency of UAV based monitoring technique, four field experiments involving different nitrogen (N) rates (0–360 kg N ha−1) and seven winter wheat (Triticum aestivum L.) varieties were conducted at different eco-sites (Sihong, Rugao, and Xinghua) during 2015–2019. A multispectral active canopy sensor (RapidSCAN CS-45; Holland Scientific Inc., Lincoln, NE, USA) mounted on a multirotor UAV platform was used to collect the canopy spectral reflectance data of winter wheat at key growth stages, three growth parameters (leaf area index (LAI), leaf dry matter (LDM), plant dry matter (PDM)) and three N indicators (leaf N accumulation (LNA), plant N accumulation (PNA) and N nutrition index (NNI)) were measured synchronously. The quantitative linear relationships between spectral data and six growth indices were systematically analyzed. For monitoring growth and N nutrition status at Feekes stages 6.0–10.0, 10.3–11.1 or entire growth stages, red edge ratio vegetation index (RERVI), red edge chlorophyll index (CIRE) and difference vegetation index (DVI) performed the best among the red edge band-based and red-based vegetation indices, respectively. Across all growth stages, DVI was highly correlated with LAI (R2 = 0.78), LDM (R2 = 0.61), PDM (R2 = 0.63), LNA (R2 = 0.65) and PNA (R2 = 0.73), whereas the relationships between RERVI (R2 = 0.62), CIRE (R2 = 0.62) and NNI had high coefficients of determination. The developed models performed better in monitoring growth indices and N status at Feekes stages 10.3–11.1 than Feekes stages 6.0–10.0. To sum it up, the UAV-mounted active sensor system is able to rapidly monitor the growth and N nutrition status of winter wheat and can be deployed for UAV-based remote-sensing of crops.
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•Stability and in vitro anti-inflammatory effect of PYQ1-EPS on a model of IBD were assessed.•PYQ1-EPS reduced IL-1β, IL-6, IL-8, IL-12A levels and up-regulated IL-10 level.•PYQ1-EPS ...blocked the activation of NF-κB and MAPK signaling pathways.•PYQ1-EPS restored the lipid content of inflammation model cells to 90.7% of the untreated cells.
Paenibacillus polymyxa exopolysaccharide PYQ1-EPS is a homogeneous glucomannan-type polysaccharide. In this work, its stability and reparative effects on the in vitro model of inflammatory bowel disease (IBD) and possible mechanisms were investigated to expand its application fields. The results showed that PYQ1-EPS significantly increased the cell viability, inhibited the expression of pro-inflammatory cytokines and promoted the expression of anti-inflammatory cytokines, which effectively blocked the activation of NF-κB and MAPK signaling pathways. Meanwhile, it was found that the anti-inflammatory effect of PYQ1-EPS was closely related to the lipid metabolism of cells, which restored the lipid content of inflammation model cells to 90.7% of the untreated cells. This is the first report that bacterial polysaccharides inhibit gastrointestinal inflammation by modulating lipid metabolism. Upon the understanding of its functional mechanisms, our work demonstrated that PYQ1-EPS has great potential to be developed as a functional food for gastrointestinal protection.
Internal tandem duplication (ITD) mutations within the FMS-like receptor tyrosine kinase-3 (FLT3) can be found in up to 25% to 30% of acute myeloid leukemia (AML) patients and confer a poor ...prognosis. Although FLT3 tyrosine kinase inhibitors (TKIs) have shown clinical responses, they cannot eliminate primitive FLT3-ITD+ AML cells, which are potential sources of relapse. Therefore, elucidating the mechanisms underlying FLT3-ITD+ AML maintenance and drug resistance is essential to develop novel effective treatment strategies. Here, we demonstrate that FLT3 inhibition induces histone deacetylase 8 (HDAC8) upregulation through FOXO1- and FOXO3-mediated transactivation in FLT3-ITD+ AML cells. Upregulated HDAC8 deacetylates and inactivates p53, leading to leukemia maintenance and drug resistance upon TKI treatment. Genetic or pharmacological inhibition of HDAC8 reactivates p53, abrogates leukemia maintenance, and significantly enhances TKI-mediated elimination of FLT3-ITD+ AML cells. Importantly, in FLT3-ITD+ AML patient–derived xenograft models, the combination of FLT3 TKI (AC220) and an HDAC8 inhibitor (22d) significantly inhibits leukemia progression and effectively reduces primitive FLT3-ITD+ AML cells. Moreover, we extend these findings to an AML subtype harboring another tyrosine kinase–activating mutation. In conclusion, our study demonstrates that HDAC8 upregulation is an important mechanism to resist TKIs and promote leukemia maintenance and suggests that combining HDAC8 inhibition with TKI treatment could be a promising strategy to treat FLT3-ITD+ AML and other tyrosine kinase mutation–harboring leukemias.
•FLT3 inhibition induces HDAC8 upregulation through FOXO1- and FOXO3-mediated transactivation in FLT3-ITD+ AML.•Targeting HDAC8 activates p53 and enhances FLT3 TKI–mediated elimination of FLT3-ITD+ AML.
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A remote sensing method combining remote sensing and ground surveying is proposed to extract tidal flat topographic information via the spatial distribution characteristics of tidal flat surface ...features. Based on the eastern Chongming beach of the Yangtze Estuary and Landsat-5 satellite images, this study identifies the spatial distribution characteristics of tidal flat features using field-based RTK data and spectral data. The remote sensing method for extracting the geometric and physical characteristics of linear and surface geographical elements on tidal flats and the elevation assignment method are discussed. The effectiveness of this method is verified by the quality of the resultant tidal flat DEM. The results show that the use of spatial distribution features in remote sensing images can provide rich topographic information. The DEM results have an accuracy of 0.16 m, are in line with the basic topographic patterns of tidal flats, and can describe local microscale geomorphic features. This technique solves the problem of a single topographic information source in current remote sensing measurement methods and provides technical support for detecting dynamic changes in coastal zones by using remote sensing technology.
4-Methylcatechol (4-MC) is an agonist of various neurotrophic factors, which can upregulate the expression of Heme oxygenase 1 (HO-1) protein by activating nuclear factor erythroid 2-related factor 2 ...(Nrf2), thereby inhibiting oxidative stress-induced neural stem cell death. During RANKL-stimulated osteoclast differentiation, intracellular reactive oxygen species (ROS) levels were increased. Nonetheless, the effect of 4-MC on osteoclast formation and bone resorption function has not been researched. In this study, we investigated the effect of HO-1 upregulation by 4-MC on RANKL-induced osteoclastogenesis and explored the molecular mechanism of HO-1 upregulation by 4-MC. We found that the small molecule compound 4-MC could bind to Keap1 amino acid residue of glycine GLY 367, isoleucine ILE 559 and valine VAL 606, with a predicted binding energy of −4.99 kcal/mol. 4-MC was found to inhibit osteoclast differentiation in vitro by activating Nrf2 to scavenge ROS, inhibiting NF-κB phosphorylation, and alleviating osteoporosis in ovariectomized (OVX) mice. Taken together, 4-MC reduces ROS by inhibiting Keap1, thereby preventing OVX-induced bone loss.
•Combination of database chip data and basic experiments.•Methylcatechol (4-MC) attenuates osteoclastogenesis.•4-MC protects bone mass in mice by regulating ROS/Keap1/Nrf2 signalling axis.•Molecular docking predicted the binding site of 4-MC to protein KEAP1.•4-MC reduces reactive oxygen species required for osteoclast differentiation.
Jets caused by burst tubes erode the surrounding soil, eventually leading to issues such as ground collapse. It is therefore highly important to study the mechanisms of soil erosion caused by jets ...after pipeline leakage. To investigate the water–soil interaction mechanisms of pipe leakage, this study used transparent soil and developed a three-dimensional experimental device to observe the fluidization process. Changes in the boundary of the fluidization transition area were investigated, and a formula for calculating the soil damage area was derived. The results showed three different shapes of the fluidized cavity appearing in the fluidization process. The particles initially moved upward and then gradually transitioned into a state of backflow. The effects of particle size, upper load, and porosity on fluidization were also analyzed. It was found that soil with a large particle size and a lower porosity under a heavy upper load can effectively restrain fluidization. Therefore, large-diameter and dense soil can be used as pipe-covering material.
This letter presents a low-cost third-harmonic mixer suitable for <inline-formula> <tex-math notation="LaTeX">{W} </tex-math></inline-formula>-band retrodirective systems. Measured results show that ...when fixing the local oscillator (LO) frequency at 35 GHz, the conversion loss (CL) below 11 dB is achieved over the radio frequency (RF) range of 100-110 GHz with intermediate frequency (IF) from dc to 5 GHz, while for the RF range of 108 GHz, the minimum CL of 6.8 dB is obtained. Therefore, the presented mixer exhibits an excellent performance with low CL in comparison with that of a normal subharmonic mixer (SHM). The isolations of RF/LO and RF/IF are improved to the level of 35 and 38 dB, respectively. The simulated and measured isolations of LO/RF are 41 and 37 dB, respectively. This mixer has properties of low LO frequencies, high isolations, and low CL; therefore, it provides a high-performance and low-cost alternative solution for the applications of retrodirective systems.
Objective
To explore differences in prognosis between adenocarcinoma (AC) and squamous cell carcinoma (SCC) and to explore feasibility of ovarian preservation in stage IB–IIA cervical cancer (CC).
...Materials and methods
Medical records of 810 patients (682 SCC + 128 AC) with stage IB–IIA CC were reviewed. Clinical and pathological characters of the two groups were compared using the chi-squared test. Kaplan–Meier survival analysis was used in univariate analysis of prognostic factors. Multivariate analysis of prognostic factors was conducted by the Cox hazards regression model.
Results
The incidence of LVSI (lymphovascular space invasion) and poor cell differentiation in SCC patients was higher than that in AC patients (23.90% vs. 8.59%,
P
< 0.05; and 54.25% vs. 28.91%,
P
< 0.05). Results of univariate analysis showed that cell differentiation, clinical stage, lymph node metastasis (LNM), ovarian metastasis (OM), parametrial involvement (PI), LVSI, depth of stromal invasion, and tumor size were related to the prognosis of patients with stage IB–IIA CC (
P
< 0.05). Results of multivariate analysis showed that cell differentiation, clinical stage, and LNM were independent prognostic factors for patients with stage IB–IIA CC. There was no difference in 5-year survival rate between SCC patients and AC patients (87.3% vs. 82.4%;
P
> 0.05). In AC patients, there was no difference in the 5-year survival rate between patients with ovarian retention and patients with bilateral ovariectomy (75% vs. 86.6%;
P
> 0.05).
Conclusions
In stage IB–IIA CC, there is no difference in prognosis between AC and SCC. The ovaries of stage IB–IIA1 AC patients under age 45 might be preserved.
Navigation accuracy is one of the key performance indicators of an inertial navigation system (INS). Requirements for an accuracy assessment of an INS in a real work environment are exceedingly ...urgent because of enormous differences between real work and laboratory test environments. An attitude accuracy assessment of an INS based on the intensified high dynamic star tracker (IHDST) is particularly suitable for a real complex dynamic environment. However, the coupled systematic coordinate errors of an INS and the IHDST severely decrease the attitude assessment accuracy of an INS. Given that, a high-accuracy decoupling estimation method of the above systematic coordinate errors based on the constrained least squares (CLS) method is proposed in this paper. The reference frame of the IHDST is firstly converted to be consistent with that of the INS because their reference frames are completely different. Thereafter, the decoupling estimation model of the systematic coordinate errors is established and the CLS-based optimization method is utilized to estimate errors accurately. After compensating for error, the attitude accuracy of an INS can be assessed based on IHDST accurately. Both simulated experiments and real flight experiments of aircraft are conducted, and the experimental results demonstrate that the proposed method is effective and shows excellent performance for the attitude accuracy assessment of an INS in a real work environment.
The product of leaf area index (LAI) and clumping index (CI) quantifies the effective leaf abundance and distribution across the landscape, and therefore, governs the radiation absorption, ...evapotranspiration, and carbon assimilation processes in the terrestrial ecosystems. Previous studies were mainly focused on developing inversion methods applicable to large scale for retrieving LAI and CI from multi-angular satellite observations. However, a few studies focused on quantifying the sensitivity of canopy bidirectional reflectance distribution function (BRDF) to changes in CI in a forward manner, hampering an accurate understanding of the relationship between CI and BRDF. In this study, we simulated how BRDF responds to changes in CI in Qinghai spruce (
Picea crassifolia
) forests based on a 3D radiative transfer model LESS and ground-measured data. We found that the LESS model effectively simulated the hot-spot, roof, and bowl-edge characteristics of the canopy BRDF by changing the sun-sensor geometry. We constructed forest scenes with variable CI (ranging from 0.4 to 0.8) to investigate the clumping effect on BRDF with different solar and observation angles. The red band bidirectional reflectance factor (BRF) showed higher sensitivity to changes in CI than that in the near-infrared (NIR) band. Canopy BRFs in the red band along the principal plane and cross principal planes measured in different seasons showed consistent sensitivity to changes in CI, suggesting that the red band BRF is helpful for CI inversion for forests with different levels of foliage clumping. In the NIR band, canopy BRFs along the principal plane measured in growing seasons with solar zenith angle (SZA) <40° and the cross principal plane measured in non-growing seasons (with SZA >40°) were sensitive to changes in CI in highly clumped forests (with CI ranging from 0.4 to 0.6). However, canopy BRF in the NIR band showed low sensitivity to changes in CI in highly clumped forests (CI <0.6), especially along the cross principal plane when SZA was approximately 10°. The simulated BRFs in the red and NIR bands showed relatively low sensitivity to changes in SZAs at a VZA of 40° and 0°, respectively. We highly recommend including the red band BRF for CI retrievals, and using a VZA of 40° in the red band and 0° in the NIR band may help reduce the CI estimation uncertainty caused by changes in SZA. This research provides a new perspective for understanding the sensitivity of multi-angular satellite data to changes in canopy structural characteristics of vegetation in global ecosystem studies and may help improve CI estimations using the multiangular optical remote sensing data.
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