Microstructure and properties of a deformation-processed Cu-Cr-Ag in situ composite by directional solidification

Cu-7Cr-0.07Ag alloys were prepared by casting and directional solidification, from which deformation-processed in situ composites were prepared by thermo-mechanical processing. The microstructure, mechanical properties, and electrical properties were investigated using optical microscopy, scanning electronic microscopy, tensile testing, and a micro-ohmmeter. The second-phase Cr grains of the directional solidification Cu-7Cr-0.07Ag in situ composite were parallel to the drawing direction and were finer, which led to a higher tensile strength and a better combination of properties

Molecular Cloning and Characterization of Two Genes Encoding Dihydroflavonol-4-Reductase from Populus trichocarpa

Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is a rate-limited enzyme in the biosynthesis of anthocyanins and condensed tannins (proanthocyanidins) that catalyzes the reduction of dihydroflavonols to leucoanthocyanins. In this study, two full-length transcripts encoding for PtrDFR1 and PtrDFR2 were isolated from Populus trichocarpa. Sequence alignment of the two PtrDFRs with other known DFRs reveals the homology of these genes. The expression profile of PtrDFRs was investigated in various tissues of P. trichocarpa. To determine their functions, two PtrDFRs were overexpressed in tobacco (Nicotiana tabacum) via Agrobacterium-mediated transformation. The associated color change in the flowers was observed in all 35S:PtrDFR1 lines, but not in 35S:PtrDFR2 lines. Compared to the wild-type control, a significantly higher accumulation of anthocyanins was detected in transgenic plants harboring the PtrDFR1. Furthermore, overexpressing PtrDFR1 in Chinese white poplar (P. tomentosa Carr.) resulted in a higher accumulation of both anthocyanins and condensed tannins, whereas constitutively expressing PtrDFR2 only improved condensed tannin accumulation, indicating the potential regulation of condensed tannins by PtrDFR2 in the biosynthetic pathway in poplars

Influence of Nitrogen Partial Pressure on the Microstructure and Properties of TiN Coatings

TiN coatings were prepared by using multi-arc ion plating technique at different N-2 partial pressures. The surface morphology of the coatings was characterized by using a tabletop scanning electron microscope. The cross-sectional microstructure was investigated by using a field emission scanning electron microscope. The phase composition was evaluated by using an X-Ray diffractometer. The hardness and cohesion were measured by using a nano indentation tester and a scratch instrument, respectively. The results show that the number and size of macro-particles decrease and the compactness of TiN coating increases with the increase of the N-2 partial pressure. The hardness and cohesion of the coating increase gradually with increasing N-2 partial pressures and reach a peak at 0.6 Pa; then the hardness and cohesion are significantly lower at higher N-2 partial pressures

Soil Organic Carbon Prediction Using Sentinel-2 Data and Environmental Variables in a Karst Trough Valley Area of Southwest China

Climate change is closely linked to changes in soil organic carbon (SOC) content, which affects the terrestrial carbon cycle. Consequently, it is essential for carbon accounting and sustainable soil management to predict SOC content accurately. Although there has been an extensive utilization of optical remote sensing data and environmental factors to predict SOC content, few studies have explored their applicability in karst areas. Therefore, it remains unclear how SOC content can be accurately simulated in these areas. In this study, 160 soil samples, 8 environmental covariates and 14 optical remote sensing variables were used to build SOC content prediction models. Three machine learning models, i.e., support vector machine (SVM), random forest (RF) and extreme gradient boosting (XGBoost), were applied for each of three land use classes, including the entire study area, as well as farmland and forest areas. The variables with the greatest influence were the optical remote sensing bands, derived indices, as well as precipitation and temperature for forest areas, and optical remote sensing band11 and Pop-density for farmland. The results from this study suggest that RF and XGBoost are superior to SVM in prediction accuracy. Additionally, the simulation accuracy of the RF model for the forest areas (R2 = 0.32, RMSE = 6.81, MAE = 5.63) and of the XGBoost model for farmland areas (R2 = 0.28, RMSE = 4.03, MAE = 3.27) was the greatest. The prediction model based on different land use types could obtain a higher simulation accuracy than that based on the whole study area. These findings provide new insights for the estimation of SOC content with high precision in karst areas

Effects of various agents on estrogenic control of LPS-induced TNF-α production in BMMs.

<p>(A) Cells were incubated for 24 h with 1 µg/ml LPS alone or in the presence of BSA (10 nM), 17β-estradiol (E₂, 1 nM), E₂-BSA (10 nM), E₂ plus a 10-fold excess of tamoxifen (Ta), ICI 182780 (ICI), or G-15. (B) Cells were preincubated with BAPTA (10 µM) or SB203580 (SB, 20 µM) for 30 min before the addition of LPS (1 µg/ml) or LPS plus E₂ (1 nM) for 24 h. The culture media were collected to measure TNF-α concentrations using ELISA. The relative expression of TNF-α was evaluated with results obtained from LPS-stimulated macrophages. The results are expressed as the means ± the SEMs from three independent experiments. *<i>P</i><0.05 compared to the LPS control.</p

Detection of membrane estrogen receptors in BMMs.

<p>(A) Flow cytometry and (B) confocal laser scanning microscopy analyses of membrane estrogen receptors in BMMs. Intact cells labeled with E₂-BSA-FITC or BSA-FITC alone as a control. For GPR30 detection, intact cells were pretreated with anti-GPR30 followed by FITC-conjugated secondary antibody. (C) Western blotting analyses of GPR30 protein from the membrane (mem), cytoplasmic (cyt), or nuclear (nu) fractions of BMMs. The results were verified by at least three independent experiments. The bar indicates 10 µm.</p

Specificity of E₂-BSA-FITC binding on BMMs.

<p>Cells were incubated for 15₂-BSA-FITC (1×10⁻⁶ M) in the absence (control) or in the presence of a 10-fold excess of different unlabeled materials: 17β-estradiol (E₂), E₂-BSA, tamoxifen (Ta), ICI 182780 (ICI), or G-15. Fluorescence intensity was analyzed by flow cytometry. The results were verified by at least three independent experiments.</p