In this study, Si-doped Cu<sub>2</sub>ZnSnS<sub>4</sub> compounds (Cu<sub>2</sub>ZnSn<sub>1-x</sub>Si<sub>x</sub>S<sub>4</sub>, 0 ≤ x ≤ 1) were...In this study, Si-doped Cu<sub>2</sub>ZnSnS<sub>4</sub> compounds (Cu<sub>2</sub>ZnSn<sub>1-x</sub>Si<sub>x</sub>S<sub>4</sub>, 0 ≤ x ≤ 1) were prepared by solid state reaction method for use of materials for photovoltaic cells. The structural and spectroscopic properties of the as-prepared compounds were studied by X-ray diffraction (XRD), <sup>119</sup>Sn, <sup>29</sup>Si and <sup>65</sup>Cu Magic Angle Spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The Si-substitution in the Sn-site induces three different types of XRD patterns which depend largely on the Si content in the compound. For 0 ≤ x ≤ 0.5, XRD analysis reveals the presence of a pure tetragonal phase of solid solution with I-42m as a space group. Mixed tetragonal and orthorhombic phases were observed for 0.5 < x < 0.8, followed by a pure orthorhombic structure with a space group Pmn2<sub>1</sub> at high content of Si (x ≥ 0.8). <sup>119</sup>Sn MAS NMR spectra show the presence of Sn/Si disorder as a function of the Si content. The <sup>65</sup>Cu MAS NMR spectra of the quadratic solid solution confirm the presence of the two copper sites (Cu-2a and Cu-2c) at 780 ppm while in the case of the orthorhombic solid solution samples, a very broad band is observed. The optical properties were investigated of all compounds by UV-Vis diffuse reflectance and the obtained optical band gap values (1.31 to 2.43 eV) confirm a semiconductor character.展开更多
Background: Wnt signalling inhibitors (Dickkopf-1 and Sclerostin) signalling play a role in vascular development and may contribute to calcification. Aim: To investigate the association between Dickkopf-1 and sclerost...Background: Wnt signalling inhibitors (Dickkopf-1 and Sclerostin) signalling play a role in vascular development and may contribute to calcification. Aim: To investigate the association between Dickkopf-1 and sclerostin serum concentrations in children undergoing maintenance hemodialysis with intimal medial thickness and peak systolic velocity of the main arteries. Patients and Methods: A study was conducted on 40 children undergoing maintenance hemodialysis and controls of the same age and sex. The study measured the initial medial thickness (IMT) and peak systolic velocity (PSV) of the main vessels (carotid, ulnar, and femoral). Dickkopf-1 and sclerostin serum levels in both groups were assessed, and a routine investigation was performed. Results: The findings indicate that the levels of serum Dickkopf-1 and Sclerostin were significantly higher in the hemodialysis group 2540.65 (2215.4 - 2909.2 pg/ml) and 1.17 (0.85 - 2.03 ng/ml)respectively (P = 0.001), compared to their control group it was 1110.45 (885.45 - 1527.65 pg/ml) and 0.28 (0.25 - 0.32 ng/ml)) respectively P = 0.001. Additionally, there was a significant increase in intima-media thickness (IMT) with a decrease in peak systolic velocity (PSV) in the main blood vessels, including the carotid, ulnar, and femoral arteries. A significant correlation was also observed between Dickkopf-1 and sclerostin levels and IMT of the carotid, ulnar, and femoral arteries. Conclusion: Wnt signalling inhibitors (Dickkopf-1 and Sclerostin) exert effects beyond the bone and significantly contribute to early vascular calcification in pediatric patients undergoing maintenance hemodialysis.展开更多
文摘In this study, Si-doped Cu<sub>2</sub>ZnSnS<sub>4</sub> compounds (Cu<sub>2</sub>ZnSn<sub>1-x</sub>Si<sub>x</sub>S<sub>4</sub>, 0 ≤ x ≤ 1) were prepared by solid state reaction method for use of materials for photovoltaic cells. The structural and spectroscopic properties of the as-prepared compounds were studied by X-ray diffraction (XRD), <sup>119</sup>Sn, <sup>29</sup>Si and <sup>65</sup>Cu Magic Angle Spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The Si-substitution in the Sn-site induces three different types of XRD patterns which depend largely on the Si content in the compound. For 0 ≤ x ≤ 0.5, XRD analysis reveals the presence of a pure tetragonal phase of solid solution with I-42m as a space group. Mixed tetragonal and orthorhombic phases were observed for 0.5 < x < 0.8, followed by a pure orthorhombic structure with a space group Pmn2<sub>1</sub> at high content of Si (x ≥ 0.8). <sup>119</sup>Sn MAS NMR spectra show the presence of Sn/Si disorder as a function of the Si content. The <sup>65</sup>Cu MAS NMR spectra of the quadratic solid solution confirm the presence of the two copper sites (Cu-2a and Cu-2c) at 780 ppm while in the case of the orthorhombic solid solution samples, a very broad band is observed. The optical properties were investigated of all compounds by UV-Vis diffuse reflectance and the obtained optical band gap values (1.31 to 2.43 eV) confirm a semiconductor character.
文摘Background: Wnt signalling inhibitors (Dickkopf-1 and Sclerostin) signalling play a role in vascular development and may contribute to calcification. Aim: To investigate the association between Dickkopf-1 and sclerostin serum concentrations in children undergoing maintenance hemodialysis with intimal medial thickness and peak systolic velocity of the main arteries. Patients and Methods: A study was conducted on 40 children undergoing maintenance hemodialysis and controls of the same age and sex. The study measured the initial medial thickness (IMT) and peak systolic velocity (PSV) of the main vessels (carotid, ulnar, and femoral). Dickkopf-1 and sclerostin serum levels in both groups were assessed, and a routine investigation was performed. Results: The findings indicate that the levels of serum Dickkopf-1 and Sclerostin were significantly higher in the hemodialysis group 2540.65 (2215.4 - 2909.2 pg/ml) and 1.17 (0.85 - 2.03 ng/ml)respectively (P = 0.001), compared to their control group it was 1110.45 (885.45 - 1527.65 pg/ml) and 0.28 (0.25 - 0.32 ng/ml)) respectively P = 0.001. Additionally, there was a significant increase in intima-media thickness (IMT) with a decrease in peak systolic velocity (PSV) in the main blood vessels, including the carotid, ulnar, and femoral arteries. A significant correlation was also observed between Dickkopf-1 and sclerostin levels and IMT of the carotid, ulnar, and femoral arteries. Conclusion: Wnt signalling inhibitors (Dickkopf-1 and Sclerostin) exert effects beyond the bone and significantly contribute to early vascular calcification in pediatric patients undergoing maintenance hemodialysis.
