Land surface reflectance retrieval from optical hyperspectral data collected with an unmanned aerial vehicle platform.

We present a physical-based atmospheric correction algorithm for land surface reflectance retrieval based on radiative transfer model MODTRAN 5, with which the aerosol optical thickness @550 nm (AOT@550nm), columnar water vapor (CWV) could also be estimated from the hyperspectral data collected over UAV platform. Then, the method was tested on both the synthetic and field campaign-collected hyperspectral data by an UAV-VNIRIS (UAV visible/near-infrared imaging hyperspectrometer) with the spectral range covering from 400 to 1000 nm. The retrieval results were validated with theoretical values from synthetic data and truth values from field campaign measurements. The results show that the averaged MAE (mean absolute error) and RMSE (root mean squared error) of measured and retrieved surface reflectance based on estimated AOT@550nm and CWV is 0.0134 and 0.0130. Meanwhile, the averaged MAE and RMSE of measured and retrieved surface reflectance based on ground measured AOT@550nm and CWV is 0.0101 and 0.0112. The results show that our introduced method has good agreement with the method based on ground-measured AOT@550nm and CWV. These encouraging results also indicate that the introduced physical-based atmospheric approach provides a quick and reliable way to acquire the land surface reflectance from UAV platform-observed hyperspectral data for further quantitative remote sensing applications.

Elevated heme impairs macrophage phagocytosis in endometriosis.

Endometriosis (EMS) is a chronic inflammatory disease characterized by the presence of extrauterine endometrial tissues. It has been previously reported that the refluxed blood containing viable endometrial tissues and the defective elimination of peritoneal macrophages in the pelvic cavity may involve in EMS pathogenesis. However, the mechanism by which macrophages exhibit attenuated phagocytic capability in EMS remains undetermined. Herein, we found that heme, the byproduct of lysed erythrocytes, accumulated abnormally in the peritoneal fluid (PF) of patients with EMS (14.22 µmol/L, 95% confidence interval (CI): 12.54-16.71), compared with the EMS-free group (9.517 µmol/L, 95% CI: 8.891-10.1053). This abnormal accumulation was not associated with the color of PF, phase of the menstrual cycle or severity of the disease. The reduced phagocytic ability of peritoneal macrophages (pMφs) was observed in the EMS group. Consistently, a high-concentration (30 µmol/L) heme treatment impaired EMS-pMφs phagocytosis more than a low-concentration (10 µmol/L) heme treatment. A similar phenomenon was observed in the EMS-free control pMφs (Ctrl-pMφs) and the CD14+ peripheral monocytes (CD14+ Mos). These results indicated that a high heme concentration exhibits a negative effect on macrophage phagocytosis, which supplements the mechanism of impaired scavenger function of pMφs in EMS.

Land surface temperature retrieved from airborne multispectral scanner mid-infrared and thermal-infrared data.

Land surface temperature (LST) is one of the key parameters in the physics of land surface processes at local/global scales. In this paper, a LST retrieval method was proposed from airborne multispectral scanner data comparing one mid-infrared (MIR) channel and one thermal infrared (TIR) channel with the land surface emissivity given as a priori knowledge. To remove the influence of the direct solar radiance efficiently, a relationship between the direct solar radiance and water vapor content and the view zenith angle and solar zenith angle was established. Then, LST could be retrieved with a split-window algorithm from MIR/TIR data. Finally, the proposed algorithm was applied to the actual airborne flight data and validated with in situ measurements of land surface types in the Baotou site in China on 17 October 2014. The results demonstrate that the difference between the retrieved and in situ LST was less than 1.5 K. The bais, RMSE, and standard deviation of the retrieved LST were 0.156 K, 0.883 K, and 0.869 K, respectively, for samples.

[A Method to Reconstruct Surface Reflectance Spectrum from Multispectral Image Based on Canopy Radiation Transfer Model].

Due to the lack of enough spectral bands for multi-spectral sensor, it is difficult to reconstruct surface retlectance spectrum from finite spectral information acquired by multi-spectral instrument. Here, taking into full account of the heterogeneity of pixel from remote sensing image, a method is proposed to simulate hyperspectral data from multispectral data based on canopy radiation transfer model. This method first assumes the mixed pixels contain two types of land cover, i.e., vegetation and soil. The sensitive parameters of Soil-Leaf-Canopy (SLC) model and a soil ratio factor were retrieved from multi-spectral data based on Look-Up Table (LUT) technology. Then, by combined with a soil ratio factor, all the parameters were input into the SLC model to simulate the surface reflectance spectrum from 400 to 2 400 nm. Taking Landsat Enhanced Thematic Mapper Plus (ETM+) image as reference image, the surface reflectance spectrum was simulated. The simulated reflectance spectrum revealed different feature information of different surface types. To test the performance of this method, the simulated reflectance spectrum was convolved with the Landsat ETM + spectral response curves and Moderate Resolution Imaging Spectrometer (MODIS) spectral response curves to obtain the simulated Landsat ETM+ and MODIS image. Finally, the simulated Landsat ETM+ and MODIS images were compared with the observed Landsat ETM+ and MODIS images. The results generally showed high correction coefficients (Landsat: 0.90-0.99, MODIS: 0.74-0.85) between most simulated bands and observed bands and indicated that the simulated reflectance spectrum was well simulated and reliable.

UiO-66 Selective Enrichment Integrated with Thermal Desorption GC-MS for Detection of Benzene Homologues in Ambient Air.

In this study, UiO-66 was selected as sorbent media packed in the tube to selectively enrich trace levels of benzene homologues such as benzene, toluene, and xylene (BTX) in ambient air prior to thermal desorption (TD)-GC-MS determination. A series of experiments were conducted to obtain the optimal TD conditions. The results indicated that the optimal TD parameters were as follows: desorption temperature of 180°C, desorption flow rate of 50 mL min-1, and desorption time of 30 min. Furthermore, the method based on UiO-66 enrichment integrated with TD-GC-MS for trace levels of BTX was successfully developed. It exhibited a good linearity (R 2 > 0.99) in the range of 50-1000 ng, except for p, m-xylene in the range of 100-2000 ng, and achieved the recovery of 69.4-101.3%, and the relative standard deviation of 3.8-6.4%. The detection limits of BTX were 1.6-4.0 ng; according to 10 L of sampling volume, the method detection limits would be in the range of 0.16-0.40 µg m-3. Additionally, the method was successfully applied to determine BTX in indoor air and showed good selectivity and sensitivity. In summary, the findings in this work revealed that UiO-66 was an attractive adsorbent for selective enrichment trace levels of BTX compounds in ambient air, which was favorable for the subsequent detection by TD-GC-MS.

Suppressive effect of dexamethasone on TIMP-1 production involves murine osteoblastic MC3T3-E1 cell apoptosis.

High dose glucocorticoid (GC) treatment induces osteoporosis partly via increasing osteoblast apoptosis. However, the mechanism of GC-induced apoptosis has not been fully elucidated. Osteoblast-derived tissue inhibitor of metalloproteinase-1 (TIMP-1) was recently reported to be involved in bone metabolism. Our previous study demonstrated that TIMP-1 suppressed apoptosis of the mouse bone marrow stromal cell line MBA-1 (pre-osteoblast) induced by serum deprivation. Therefore, we tested the effect of the GC dexamethasone (Dex) on TIMP-1 production in murine osteoblastic MC3T3-E1 cells and further determined whether this action is associated with Dex-induced osteoblast apoptosis. Dex decreased TIMP-1 production in MC3T3-E1 cells, and this effect was blocked by the glucocorticoid receptor (GR) antagonists, RU486 and RU40555. Recombinant TIMP-1 protein reduced caspase-3 activation and apoptosis induced by Dex in MC3T3-E1 cells. In addition, the pro-apoptotic effect of the Dex was augmented by suppression of TIMP-1 with siRNA. Furthermore, mutant TIMP-1, which has no inhibitory effects on MMPs, yet protects MC3T3-E1 cells against Dex-induced apoptosis. Our study demonstrates that Dex suppresses TIMP-1 production in osteoblasts through GR, and this effect is associated with its induction of osteoblast apoptosis. The anti-apoptotic action of TIMP-1 is independent of its inhibitory effects on MMPs activities. The decrease in TIMP-1 production caused by Dex may contribute to the mechanisms of Dex-induced bone loss.

Bioinformatics analysis of epitope-based vaccine design against the novel SARS-CoV-2.

BACKGROUND: An outbreak of infection caused by SARS-CoV-2 recently has brought a great challenge to public health. Rapid identification of immune epitopes would be an efficient way to screen the candidates for vaccine development at the time of pandemic. This study aimed to predict the protective epitopes with bioinformatics methods and resources for vaccine development. METHODS: The genome sequence and protein sequences of SARS-CoV-2 were retrieved from the National Center for Biotechnology Information (NCBI) database. ABCpred and BepiPred servers were utilized for sequential B-cell epitope analysis. Discontinuous B-cell epitopes were predicted via DiscoTope 2.0 program. IEDB server was utilized for HLA-1 and HLA-2 binding peptides computation. Surface accessibility, antigenicity, and other important features of forecasted epitopes were characterized for immunogen potential evaluation. RESULTS: A total of 63 sequential B-cell epitopes on spike protein were predicted and 4 peptides (Spike315-324, Spike333-338, Spike648-663, Spike1064-1079) exhibited high antigenicity score and good surface accessibility. Ten residues within spike protein (Gly496, Glu498, Pro499, Thr500, Leu1141, Gln1142, Pro1143, Glu1144, Leu1145, Asp1146) are forecasted as components of discontinuous B-cell epitopes. The bioinformatics analysis of HLA binding peptides within nucleocapsid protein produced 81 and 64 peptides being able to bind MHC class I and MHC class II molecules respectively. The peptides (Nucleocapsid66-75, Nucleocapsid104-112) were predicted to bind a wide spectrum of both HLA-1 and HLA-2 molecules. CONCLUSIONS: B-cell epitopes on spike protein and T-cell epitopes within nucleocapsid protein were identified and recommended for developing a protective vaccine against SARS-CoV-2.

Insights of efferocytosis in normal and pathological pregnancy.

Efferocytosis, which is known as the phagocytic clearance of dying cells by professional as well as non-professional phagocytes, including a great number of intracellular/extracellular factors and signals, is interrelated with the immune system, contributing to local and systemic homeostasis, especially in tissues with high constitutive rates of apoptosis. Accumulating studies have indicated that immune dysregulation is associated with the pathogenesis of the female reproductive system, which causes preeclampsia (PE), recurrent spontaneous abortion (RSA), ruptured ectopic pregnancy, and so on. And some studies have revealed the pleiotropic and essential role of efferocytosis in these obstetrical disorders. More specifically, the occurrence and development of these diseases were in connection with some efferocytosis-related factors and signals, such as C1q, MBL, and IL-33/ST2. In this review, we systematically review the diverse impacts of efferocytosis in immune system and discuss its relevance to normal and pathological pregnancy. These findings may instruct future basic researches as well as clinical applications of efferocytosis-related factors and signals as latent predictors or therapeutic targets on the obstetrical disorders.

IL-33/ST2 axis affects the polarization and efferocytosis of decidual macrophages in early pregnancy.

PROBLEM: To explore whether IL-33/ST2 axis modulates the polarization and efferocytosis of decidual macrophages (dMφs). METHOD OF STUDY: The phenotype characteristics of dMφs from both normal pregnant women and recurrent spontaneous abortion (RSA) patients were determined by real-time polymerase chain reaction (RT-PCR) and flow cytometry (FCM). Then, the efferocytosis and expression of IL-33 and its receptor (ST2) in dMφs were analyzed by FCM. Finally, the effects of sST2, a decoy receptor for IL-33 that inhibits the IL-33/ST2 signaling pathway, on the polarization and efferocytosis of dMφs and human macrophage cell line U937 were investigated. RESULTS: Compared with normal pregnancy, dMφs from RSA patients presented a M1 phenotype with high secretion of IL-33, whereas the expression of ST2 decreased. However, dMφs from RSA patients possessed a more powerful efferocytosis ability to clear the apoptotic decidual stromal cells (DSCs) compared with dMφs from normal pregnancy patients. Treatment with recombinant human sST2 led to the up-regulation of M1 bias and efferocytosis ability of both normal dMφs and U937. CONCLUSION: This study indicates that IL-33 secreted by dMφs promotes M2 bias at the feto-maternal interface, and as a result, RSA might attribute to the disturbance of IL-33/ST2 axis and the enhancement of efferocytosis of dMφs subsequently.

[Retrieving eco-environment factors relevant to Oncomelania snail distribution based on QuickBird image].

OBJECTIVE: To estimate snail distribution by using high spatial resolution QuickBird image on the basis of retrieving the eco-environment factors relevant to snail distribution. METHODS: Combined with the well-positioned ground data of Oncomelania snails, the meter-level high spatial resolution QuickBird image was used to retrieve the eco-environment factors related to snail distribution in Jiangxin village of Dangtu county, Anhui Province. The factors included vegetation (vegetation index and vegetation cover ratio) and soil (soil texture, soil cover type and humidity). A qualitative analysis was made by using principle component analysis, K-T transformation and supervision classification methods to retrieve the eco-environment factors. The vegetation index NDVI (Normalized Difference Vegetation Index) and MSAVI (Modified Soil Adjustment Vegetation Index) were calculated, and LAI (Leaf area index) and F (vegetation cover ratio) were retrieved. Information from QuickBird data and corresponding ground data were then used to analyze the relationship between snail distribution and environmental factors by using ArcGIS and statistical software. RESULTS: Snail data were received from 153 ground distribution spots and a GIS database on spacial distribution of snails was established. This database covered snail density, NDVI, MSAVI, LAI(NDVI), LAI(MSAVI), F(NDVI), F(MSAVI), PCA-1, PCA-2, PCA-3, KT-1, KT-2 and KT-3. Statistical analysis showed that the snail density could be estimated by LAINDVI and FMSAVI quantitatively based on the following regression model: Y = -3.919 + 1.22 LAI(MSVI) + 16.076 F(MSAVI). Decision index of the regression model was 0.2. CONCLUSIONS: A quantitative regression model between Oncomelania snail distribution and environmental variables retrieved from QuickBird images has been established, which may have a wide application prospect. KT-1, KT-2 and KT-3. Statistical analysis showed that the snail density could be estimated by LAINDVI and FMSAVI quantitatively based on the following regression model: Y = -3.919 + 1.22 LAI(MSAVI) + 16.076 F(MSAVI). Decision index of the regression model was 0.2. CONCLUSIONS: A quantitative regression model between Oncomelania snail distribution and environmental variables retrieved from QuickBird images has been established, which may have a wide application prospect.

[Inhibitory effect of resveratrol on the proliferation of synoviocytes in rheumatoid arthritis and its mechanism in vitro].

OBJECTIVE: To investigate the effect of resveratrol on the proliferation and apoptosis of synoviocytes in patients with rheumatoid arthritis (RA) in vitro and explore its mechanism. METHODS: The levels of cell proliferation of synoviocytes in RA after 24 h treated with different concentrations of resveratrol were measured by monotetrazolium colourmetric assay method. The percentages of synoviocytes apoptosis in RA after 24 h treated with different concentrations of resveratrol were tested by TUNEL and flow cytometry. The relative activities of caspase-3 were determined by colorimetric assay after 4, 8, 12, 18, and 24 h treated with resveratrol (200 micromol/L) and 12 h treated with different concentrations of resveratrol. The cleavages of pro-caspase-3 were analyzed by Western blot after 24 h treated with different concentrations of resveratrol. RESULTS: The levels of cell proliferation of synoviocytes with RA after 24 h treated with different concentrations of resveratrol were significantly decreased compared with the control group (P<0.01). The percentages of the apoptotic cells were increased of resveratrol-treated after 24 h, the apoptosis rates between the treated groups and the control group were significantly different (P<0.01). When the synoviocytes in RA were treated with 200 micromol/L resveratrol for different time respectively, the caspase-3 activity began to rise significantly at 4h, reaching the peak at 12 h, and was still much higher than that of the control group at 24 h (P<0.01). After the cells were treated with different concentrations of resveratrol for 12 h, caspase-3 activity increased in a concentration-dependent manner. After synoviocytes in RA were treated with different concentrations of resveratrol for 24 h, the expressions of pro-caspase-3 decreased as the concentration increased, the caspase-3 active fragment P11 (11 kD) appeared at 100 micromol/L and was increased at 400 micromol/L. CONCLUSION: Resveratrol inhibits the proliferation of synoviocytes and induces cell apoptosis in rheumatoid arthritis in vitro, which may relate to the activation of caspase-3.

Associations between the rs6010620 polymorphism in RTEL1 and risk of glioma: a meta-analysis of 20,711 participants.

BACKGROUND: Associations between the rs6010620 polymorphism in the regulator of telomere elongation helicase1 (RTEL1) gene and glioma have been widely reported but the results were not inconclusive. The aim of the current study was to investigate the association between the rs6010620 polymorphism in RTEL1 gene and risk of glioma by meta-analysis. MATERIALS AND METHODS: We searched PubMed, Embase, Wanfang Weipu and CNKI (China National Knowledge Infrastructure) databases, which included all research published 05 May 2014. A total of 8,292 cases and 12,419 controls from 14 case-control studies involving the rs6010620 polymorphism in the RTEL1 gene were included. Statistical analysis was performed using STATA 12.0 software. RESULTS: The results indicated that the rs6010620 polymorphism in RTEL1 gene was indeed associated with risk of glioma (OR=1.474, 95%CI=1.282-1.694, p<0.001). On subgroup analysis by ethnicity, we found associations between the rs6010620 polymorphism in the RTEL1 gene and risk of glioma in both Caucasians and Asians. CONCLUSIONS: The current meta-analysis suggested that the rs6010620 polymorphism in the RTEL1 gene might increase risk of glioma. In future, larger case-control studies are needed to confirm our results.

Sorption characteristics of cyromazine and its metabolite melamine in typical agricultural soils of China.

A myriad of physical, chemical, and biological processes controls the fate of organic contaminants in soils. The knowledge of bioavailability of a contaminant in soil can be useful to conduct environmental risk assessment. We conducted batch equilibrium experiments to investigate the sorption of cyromazine (CA) and its metabolite melamine (MA) onto five typical soils of China belonging to suborders Ali-Perudic Ferrosols, Udic Argosols, Gleyic-Stagnic Anthrosols, Ustic Cambosols, and Udic Isohumosols. Results showed that sorption of CA and MA onto soils was linear, as indicated by the Freundlich and Langmuir models. Different sorption behaviors of CA and MA were observed on the five agricultural soils, with lgK f values (Freundlich model) of 1.6505-2.6557 and 1.632-2.549, respectively. Moreover, the K f values for CA and MA were positively correlated with soil organic matter (r = 0.989, r = 0.976) and significantly negatively correlated with pH (r = -0.938, r = -0.964). The free energy of sorption of CA and MA ranged from -20.8 to -23.0 kJ mol(-1) and -20.8 to -22.8 kJ mol(-1), respectively, suggesting that the sorption of CA and MA onto the soils is primarily a physical process.

Insulin receptor substrate 1 regulates the cellular differentiation and the matrix metallopeptidase expression of preosteoblastic cells.

Insulin receptor substrate 1 (IRS1) is an essential molecule for the intracellular signaling of IGF1 and insulin, which are potent anabolic regulators of bone metabolism. Osteoblastic IRS1 is essential for maintaining bone turnover; however, the mechanism underlying this regulation remains unclear. To clarify the role of IRS1 in bone metabolism, we employed RNA interference to inhibit IRS1 gene expression and observed the effects of silencing this gene on the proliferation and differentiation of and the expression of matrix metallopeptidase (MMP) and tumor necrosis factor receptor superfamily, member 11b (TNFRSF11B) in MC3T3-E1 cells. Our results showed that IRS1 short hairpin RNAs can effectively suppress the expression of IRS1, and inhibit the phosphorylation of AKT in IRS1 pathway; reduce the expression of MMP2, MMP3, MMP13, and MMP14, decrease the expression of TNFRSF11B and RANKL (also known as tumor necrosis factor (ligand) superfamily, member 11), however increase the RANKL/TNFRSF11B ratio; decrease cell survival, proliferation, and mineralization, and impair the differentiation of MC3T3-E1 cells. The downregulation of IRS1 had no effect on the expression of MMP1. Our findings suggest that IRS1 not only promotes bone formation and mineralization but also might play roles in bone resorption partly via the regulation of MMPs and RANKL/TNFRSF11B ratio, thus regulates the bone turnover.

[Adsorption of cyromazine on five typical soils in China].

Batch equilibrium experiments were used to reveal cyromazine adsorption on five kinds of soils, namely Ali-Perudic Ferrosols collected from Yingtan of Jiangxi, Udic Argosols collected from Nanjing and Gleyic-Stagnic Anthrosols collected from Changshu of Jiangsu, Ustic Cambosols collected from Fengqiu of Henan, and Udic Isohumosols collected from Hailun of Heilongjiang. Results show that the experimental data are best described by the Freundlich and Langmuir model, while fitted successfully by the linear model. Different adsorption behaviors of Cyromazine are observed in the five tested soils, with the lgK(f) values varying from 1.6505 (cambosols), 1.6715 (argosols) and 1.7153 (ferrosols) to 2.4579 (anthrosols) and 2.6557 (isohumosols). Moreover, the Kf values are in a positive correlation to the OM of the soil (r = 0.989) but significantly negative correlated to soil pH (r = -0.938). The free energy of sorption ranged from -20.8 to -23.0 kJ/mol, indicated that the adsorption could be largely attributed to the physical adsorption.