Soil Nutrient Estimation and Mapping in Farmland Based on UAV Imaging Spectrometry.

Soil nutrient is one of the most important properties for improving farmland quality and product. Imaging spectrometry has the potential for rapid acquisition and real-time monitoring of soil characteristics. This study aims to explore the preprocessing and modeling methods of hyperspectral images obtained from an unmanned aerial vehicle (UAV) platform for estimating the soil organic matter (SOM) and soil total nitrogen (STN) in farmland. The results showed that: (1) Multiplicative Scattering Correction (MSC) performed better in reducing image scattering noise than Standard Normal Variate (SNV) transformation or spectral derivatives, and it yielded a result with higher correlation and lower signal-to-noise ratio; (2) The proposed feature selection method combining Successive Projections Algorithm (SPA) and Competitive Adaptive Reweighted Sampling algorithm (CARS), could provide selective preference for hyperspectral bands. Exploiting this method, 24 and 22 feature bands were selected for SOM and STN estimation, respectively; (3) The particle swarm optimization (PSO) algorithm was employed to obtain optimized input weights and bias values of the extreme learning machine (ELM) model for more accurate prediction of SOM and STN. The improved PSO-ELM model based on the selected preference bands achieved higher prediction accuracy (R2 of 0.73 and RPD of 1.91 for SOM, R2 of 0.63, and RPD of 1.53 for STN) than support vector machine (SVM), partial least squares regression (PLSR), and the ELM model. This study provides an important guideline for monitoring soil nutrient for precision agriculture with imaging spectrometry.

Precise Topographic Model Assisted Slope Displacement Retrieval from Small Baseline Subsets Results: Case Study over a High and Steep Mining Slope.

Due to the intrinsic side-looking geometry of synthetic aperture radar (SAR), time series interferometric SAR is only able to monitor displacements in line-of-sight (LOS) direction, which limits the accuracy of displacement measurement in landslide monitoring. This is because the LOS displacement is only a three dimensional projection of real displacement of a certain ground object. Targeting at this problem, a precise digital elevation model (DEM) assisted slope displacement retrieval method is proposed and applied to a case study over the high and steep slope of the Dagushan open pit mine. In the case study, the precise DEM generated by laser scanning is first used to minimize topographic residuals in small baseline subsets analysis. Then, the LOS displacements are converted to slope direction with assistance of the precise DEM. By comparing with ground measurements, relative root mean square errors (RMSE) of the estimated slope displacements reach approximately 12-13% for the ascending orbit, and 5.4-9.2% for the descending orbit in our study area. In order to validate the experimental results, comparison with microseism monitoring results is also conducted. Moreover, both results have found that the largest slope displacements occur on the slope part, with elevations varying from -138 m to -210 m, which corresponds to the landslide area. Moreover, there is a certain correlation with precipitation, as revealed by the displacement time series. The outcome of this article shows that rock mass structure, lithology, and precipitation are main factors affecting the stability of high and steep mining slopes.

Evaluation of effect of atorvastatin on left ventricular systolic function in rats with myocardial infarction via 2D-STI technique.

This report aims to evaluate the effect of atorvastatin (Ator) on left ventricular systolic function in myocardial infarction (MI) rats. Forty healthy adult Sprague-Dawley rats were randomly divided into four groups: Ator group, MI group, sham-operation group and normal group. The left anterior descending coronary arteries were ligated to establish the MI model; after modeling, the Ator group was treated with Ator for 4 consecutive weeks. The echocardiographic detection was performed; the left ventricular myocardial systolic peak velocities, strain and strain rates were analyzed using the 2D-STI technique. After 4 weeks, myocardial tissues were taken from all rats and received the pathological examination. Left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) in Ator group and MI group were increased after operation, but left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were decreased; myocardial function were decreased significantly (p<0.05). After Ator treatment, myocardial function at the 3rd and 4th week after operation increased significantly (p<0.05). After Ator treatment, LVEDD and LVESD decreased while LVEF and LVFS increased in Ator group at the 3rd and 4th week after operation compared with MI group (p<0.05). At the 4th week after operation, LVEDD and LVESD in Ator group were decreased compared with those at the 1st and 2nd week after operation, but LVEF and LVFS were increased compared with those at the 1st, 2nd and 3rd week after operation (p<0.05). Pathological examination showed that necrosis and fibrosis of myocardial cells and inflammatory reaction were obvious in MI group. The inflammatory reaction of myocardial cells and myocardial fibrosis were lighter in Ator group. Ator can effectively improve the left ventricular systolic function in MI rats, which could be related to the reduction of response to inflammation and fibrosis.

[A Classification Method Based on the Combination of Visible, Near-Infrared and Thermal Infrared Spectrum for Coal and Gangue Distinguishment].

Coals and gangues are the main surface dump in the coal mining process. Dynamic monitoring of those dumps using remote sensing technique is of great importance for mine environmental protection. In the traditional classification of visible and near-infrared remote sensing, part of the gangues might be misclassified as coal, due to the phenomenon of "different objects with the same spectrum", resulting in the decrease of classification accuracy. Thus, this study firstly acquired visible and near-infrared spectrums of 12 coal samples and 115 gangue samples from Tiefa mining area in China. Most of the gangue samples' spectrums are different from those of the coals, which can be easily distinguished. While, part of the gangues has the similar spectrum with coal which results in misclassification. With an effort to improve image classification accuracy, furthermore, we acquired the thermal infrared spectrum of the misclassified gangue and the coal samples. The results indicate that there are different spectral characteristics in thermal infrared band between coal and gangue samples, which can be identified easily. Therefore, we proposed a method to separate coal from gangue based on the combination of visible, near-infrared and thermal infrared spectrum. In the first palace, the method conducts measurement on the visible and near-infrared spectrums of all samples for the rough classification recurring to the MAO model. Next, the thermal infrared spectrums of the samples, mixed with gangue and coal are acquired, and the Spectral Absorption Ratio(SAR) is utilized as the evaluation index for the second classification. The fused result of classification originates in the two steps above. The method is further verified by using external samples from Tiefa, Yanzhou, Shendong and Jiangcang mining areas in China, whose results have demonstrated that the method has higher accuracy than that of the traditional classification method based on visible and near-infrared spectrum features. The research results indicates that the conjoint analytical method involving multiple spectrums can solve the phenomenon of "different objects with the same spectrum" in a single band, effectively, which will be of great referential significance in the field of terrain classification based on remote sensing technique.

[Research in Magnesite Grade Classification Based on Near Infrared Spectroscopy and ELM Algorithm].

Due to the needs of industrial development, the different content and uncertain distribution of magnesite mineral lead to great difficulties in o determining its grade, therefore, we propose a combination of near-infrared spectroscopy and the ELM magnesite grade classification model. The model can achieve rapid classification of magnesite grade. Near infrared spectroscopy, considering that different types of H group in magnesite have different absorption degrees to near-infrared spectroscopy, is used to determine the composition and content of magnesite. It is simple, fast, accurate and efficient without destroying the sample. In this paper, we take magnesite 30 group from Yingkou City, Liaoning Province Dashiqiao for the study, collecting their magnesite NIR data samples at 30×973, using principal component analysis (PCA) for data dimensionality reduction process. The main element contribution rate is greater than 99.99% obtained characteristic variables of 10, established quantitative analysis ELM algorithm mathematical model, take 20 groups of samples as the training samples (including 6 super group, 14 groups non), 10 groups of samples for testing samples (including super grade4 groups, 6 groups non), ELM algorithm model hidden layer nodes selection 20. In order to further improve the classification performance, two kinds improved ELM algorithm models are proposed: conduct optimization selection ELM for the traditional ELM input weights and threshold using the circulation patterns and integrate integration-Featured ELM based on Featured ELM. And compare to which use the artificial method, chemical method and BP neural network model approach. The results showed that magnesite grade classification with the near-infrared spectroscopy and ELM model have a distinct advantage regardless of cost or time, and the accuracy rate can reach over 90%, which provides a new way to classify magnesite grade.

[Thermal infrared spectral variation and sensitive waveband of quartzy sandstone under pressure].

In the present paper the thermal infrared spectral variation of quartz sandstone under uniaxial compression was detected by a spectroradiometer to study the sensitively responding waveband of infrared radiation excited by the pressure. The experimental result shows that the infrared spectrum varies with the load, and the variation feature is different in different wavebands. The infrared radiation intensity increases with the increase in the load within the waveband 8.0-11.5 microm (specially in 8.6-9.1 microm), and there is a quadratic correlation between them, meanwhile the signal-to-noise ratio of spectrum radiation is also higher in the waveband. But in other wavebands the correlation is worse and the signal-to-noise is also lower. This indicates that the waveband 8.0-11.5 microm is the sensitive waveband of infrared radiation to the pressure, and it is also the superior waveband for infrared remote sensing monitoring the stress and catastrophe of rock. The optimum waveband is 8.6-9.1 microm.

1alpha,25-Dihydroxyvitamin D(3) triggered vitamin D receptor and farnesoid X receptor-like effects in rat intestine and liver in vivo.

1alpha,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), a natural ligand of the vitamin D receptor (VDR), was found to increase the rat ileal Asbt and bile acid absorption. The effects of VDR, whose expression is low in liver, on hepatic transporters and enzymes are unknown. Protein and mRNA levels of target genes in the small intestine, colon and liver after intraperitoneal dosing of 1,25(OH)(2)D(3) (0-2.56 nmol/kg/day for 4 days) to the rat were determined by Western blotting and qPCR, respectively. The 1,25(OH)(2)D(3) treatment increased total Cyp3a protein and Cyp3a1 mRNA expressions in the proximal small intestine, and the short heterodimer partner (SHP), the fibroblast growth factor 15 (FGF15), organic solute transporter (Ostalpha and Ostbeta) mRNA and Asbt protein expressions in the ileum. About 50% higher portal bile acid concentration (65.1+/-14.9 vs 41.9+/-7.8 microm, p<0.05) and elevated expressions of the hepatic farnesoid X receptor (FXR) and SHP mRNA resulted with 1,25(OH)(2)D(3) treatment. Increased Bsep and Ostalpha mRNA expressions in liver and a>50% reduction in the Cyp7a1 protein level (p<0.05) and cholesterol metabolism in rat liver microsomes (p=0.002), likely consequences of the bile acid-FXR-SHP cascade and activation of the signaling pathway for Cyp7a1 inhibition by FGF15, were found. Increased hepatic multidrug resistance-associated protein (Mrp3) and multidrug resistance protein 1a (Mdr1a) mRNA and P-gp protein were also observed. It was concluded that the changes in hepatic transporters and enzymes in the rat were indirect, secondary effects of the liver FXR-SHP cascade due to increased intestinal absorption of bile acids and elevated levels of FGF15, events that led to the activation of FXR.

Up-regulation of transporters and enzymes by the vitamin D receptor ligands, 1alpha,25-dihydroxyvitamin D3 and vitamin D analogs, in the Caco-2 cell monolayer.

The effects of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] on gene expression and function were studied in Caco-2 cells. Microarray analyses, real-time quantitative polymerase chain reactions, and Western blotting were used to determine the mRNA and protein expression of transporters and enzymes after 1,25(OH)(2)D(3) or vehicle (0.1% ethanol) treatment for 1, 3, 6, and 10 days. The mRNA and protein expressions of the apical sodium-dependent bile acid transporter, oligopeptide transporter 1, multidrug resistance-associated protein (MRP) 3, and sulfotransferase 1E1 remained unchanged with 1,25(OH)(2)D(3) treatment, whereas those for CYP3A4, multidrug resistance protein 1, and MRP2 were significantly increased (P < 0.05). 1,25(OH)(2)D(3) treatment significantly enhanced MRP4 protein expression by increasing protein stability without affecting mRNA expression, as confirmed in cycloheximide experiments. Marked increase in 6beta-hydroxylation of testosterone by CYP3A4 was also observed in the 6-day 1,25(OH)(2)D(3)-treated (100 nM) cell lysate. The transport of [(3)H]digoxin, the P-glycoprotein (P-gp) substrate, after treatment with 100 nM 1,25(OH)(2)D(3) for 3 days revealed a higher apparent permeability (P(app)) value in the basal (B)-to-apical (A) direction over that of vehicle treatment (15.1 +/- 0.53 x 10(-6) versus 11.8 +/- 0.58 x 10(-6) cm/s; P < 0.05), whereas the P(app) in the A-to-B direction was unchanged; the efflux ratio was increased (from 5.8 to 8.0). Reduced cellular retention of 5-(and-6)-carboxy-2',7'-dichlorofluorescein, suggestive of higher MRP2 activity, was observed in the 3-day 100 nM 1,25(OH)(2)D(3)-treated cells over controls. Higher protein expression of CYP3A4, MRP2, P-gp, and MRP4 was also observed after a 6-day treatment with other vitamin D analogs (100 nM 1alpha-hydroxyvitamin D(3),1alpha-hydroxyvitamin D(2) or Hectorol, and 25-hydroxyvitamin D(3)) in Caco-2 cells, suggesting a role of 1,25(OH)(2)D(3) and analogs in the activation of enzymes and transporters via the vitamin D receptor.

The Caco-2 cell monolayer: usefulness and limitations.

BACKGROUND: The Caco-2 monolayer has been used extensively for the high-throughput screening of drug permeability and identification of substrates, inhibitors, and inducers of intestinal transporters, especially P-glycoprotein (P-gp). Traditionally, the Caco-2 monolayer is viewed as a single barrier rather than a polarized cell monolayer consisting of metabolic enzymes that are sandwiched between two membrane barriers with distinctly different transporters. OBJECTIVE: This review addressed the usefulness and limitations of the Caco-2 cell monolayer in drug discovery and mechanistic studies. METHODS: This mini-review covered applications of the Caco-2 monolayer, clarified misconceptions, and critically addressed issues on data interpretation. CONCLUSION: The catenary model extends the usefulness of Caco-2 monolayer and provides proper mechanistic insight and data interpretation.

P-glycoprotein and an unstirred water layer barring digoxin absorption in the vascularly perfused rat small intestine preparation: induction studies with pregnenolone-16alpha-carbonitrile.

Digoxin, a substrate of P-glycoprotein (Pgp) and cytochrome P450 3a (Cyp3a), was used to illustrate the inductive effects of pregnenolone-16alpha-carbonitrile (PCN), a ligand of the pregnane X receptor, on the absorption and disposition of [3H]digoxin in the vascularly perfused rat small intestine preparation. Although increased Cyp3a protein was observed with Western blotting analysis after PCN treatment, metabolism of digoxin to the digoxigenin bis-digitoxoside metabolite in the rat small intestine remained insignificant (<4% dose). PCN pretreatment significantly decreased blood perfusate [3H]digoxin concentrations for both systemic and intraluminal administrations of [3H]digoxin due to increased Pgp levels. The apical secretion by Pgp increased at 90 min with PCN treatment, from 11.2 +/- 5.1% of dose to 20.1 +/- 8.6% of dose after systemic administration of [3H]digoxin; this increase was, however, statistically insignificant (P = 0.13) because of the high variability among preparations. When the composite data for the control and PCN-treated preparations were fit to published physiologically based pharmacokinetic models: the traditional model and the segregated flow model, suboptimal parameters were obtained. The data were further fit to expanded models with a bilayer membrane compartment housing the Pgp adjacent to the apical membrane, or an unstirred water layer (UWL) external to the apical membrane. The models with the UWL yielded improved fits and reasonable parameters associated with digoxin absorption, suggesting that the UWL posed as a barrier for digoxin absorption. Similar results were obtained with the segmental models (the segmental traditional model and the segmental segregated flow model) using the UWL, when heterogeneous distributions of Pgp in the duodenum, jejunum, and ileum were considered.

[Model experiment and numerical simulation of marginal pressure in the flow field downstream of the stenostic vessel in vitro].

For the defects of interpreting the relationship between the distribution and severity of vascular stenostic disease and the low shear stress, the study focus on and explore the rules of the pressure distribution and variation downstream of the stenostic vessel with the numerical simulation and the hydrodynamic model of turbulent flow separation area for in vitro experiment. The results reveal that there is a good compatibility between the model experiment and the numerical simulation; there exists a marked pressure decrease downstream of the stenosis. And the distribution area of low pressure is similar to the characteristic distribution of the stenostic vessel diseases. The study suggested that the numerical simulation can be applied in the study of micro-flow field; the presure distribution and variatioin downstream of the stenostic vessel maybe another factor to trigger the pathogenesis of vessel stenostic diseases.

Transactivation of rat apical sodium-dependent bile acid transporter and increased bile acid transport by 1alpha,25-dihydroxyvitamin D3 via the vitamin D receptor.

Transactivation of the rat apical sodium-dependent bile acid transporter (ASBT; Slc10a2) by 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] via the vitamin D receptor (VDR), was studied. Levels of ASBT protein and mRNA were low in the duodenum and high in the ileum, and both were induced by 1,25(OH)(2)D(3). The nuclear receptor protein, VDR, was present uniformly in the duodenum, jejunum, and ileum of the rat small intestine. The physiological relevance of ASBT induction by 1,25(OH)(2)D(3) was assessed by measuring absorption of cholylsarcosine, a non-metabolized synthetic bile acid analog, from duodenal or ileal closed loops of the perfused rat small intestine preparation. Absorption of cholylsarcosine was much greater from the ileal segment (28-fold that of the duodenum under control conditions) and was enhanced with 1,25(OH)(2)D(3) treatment. Transient transfection analysis of the rat ASBT promoter in Caco-2 cells revealed concentration-dependent enhancement of luciferase reporter activity after treatment with 1,25(OH)(2)D(3). The activation by 1,25(OH)(2)D(3) was abrogated after site-directed mutagenesis or deletion of the vitamin D response element (VDRE) in the ASBT promoter. Gel-shift mobility assays of nuclear extracts from rat ileum showed that both rat retinoid X receptor and VDR were bound to the VDRE. The results indicate that rat ASBT gene expression is activated by 1,25(OH)(2)D(3) by specific binding to the VDRE and that such activation enhances ileal bile acid transport. Human ABST mRNA and promoter activity were also increased in Caco-2 cells treated with 1,25(OH)(2)D(3), suggesting a physiological role of VDR in human ileal bile acid homeostasis.

[A preliminary study on the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds in vitro].

Focus on the defects of the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds (such as the limited data, great amount of work and low reproducibility), we combine the earlier research results and the basic rules of the velocity spectrum image, and employing the visual basics plateau, to design and develop a software to extract the velocity signals from the spectrum image automatically. Compare the mean velocity and RNS between the PIV and the PDU resulting from the method, the correlations are r = 0.93 and r = 0.78 respectively. The study reveals the software increase the amount of valid data, decrease the amount of work and increase reproducibility of the signals extraction. The method may be an effective way to analyse the velocity spectrum image of PDU in clinic.

[Design and adjustment of a hydrodynamic model of turbulent flow separation area for in vitro experiment on the downstream of tubal stenosis].

This paper reports the establishment of a model of turbulent flow separation area for experiment on the downstream of tubal stenosis, and adjust it to cooperate with the velocity and turbulent shear stress (TSS) detection by means of the particle image velocimetry (PIV), and with the pressure detection of pressure sensor in vitro. The velocity, TSS and wall pressure characteristics of the downstream of tubal stenosis were quantitatively detected and analyzed via the PIV and pressure sensor. And the hydrodynamic characteristics of the velocity, TSS and wall pressure in the flow separation area were primarily understood. The model can cooperate smoothly with the PIV and pressure sensor to detect the velocity, TSS and wall pressure; there exist low velocity, low TSS and low pressure in the flow separation area downstream of tubal stenosis.