Magnesium Supplementation Attenuates Pulmonary Hypertension via Regulation of Magnesium Transporters

Pulmonary hypertension (PH) is characterized by profound vascular remodeling and altered Ca²⁺ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Magnesium ion (Mg²⁺), a natural Ca²⁺ antagonist and a cofactor for numerous enzymes, is crucial for regulating diverse cellular functions, but its roles in PH remains unclear. Here, we examined the roles of Mg²⁺ and its transporters in PH development. Chronic hypoxia and monocrotaline induced significant PH in adult male rats. It was associated with a reduction of [Mg²⁺]_i in PASMCs, a significant increase in gene expressions of Cnnm2, Hip14, Hip14l, Magt1, Mmgt1, Mrs2, Nipa1, Nipa2, Slc41a1, Slc41a2 and Trpm7; upregulation of SLC41A1, SLC41A2, CNNM2, and TRPM7 proteins; and downregulation of SLC41A3 mRNA and protein. Mg²⁺ supplement attenuated pulmonary arterial pressure, right heart hypertrophy, and medial wall thickening of pulmonary arteries, and reversed the changes in the expression of Mg²⁺ transporters. Incubation of PASMCs with a high concentration of Mg²⁺ markedly inhibited PASMC proliferation and migration, and increased apoptosis, whereas a low level of Mg²⁺ produced the opposite effects. siRNA targeting Slc41a1/2, Cnnm2, and Trpm7 attenuated PASMC proliferation and migration, but promoted apoptosis; and Slc41a3 overexpression also caused similar effects. Moreover, siRNA targeting Slc41a1 or high [Mg²⁺] incubation inhibited hypoxia-induced upregulation and nuclear translocation of NFATc3 in PASMCs. The results, for the first time, provide the supportive evidence that Mg²⁺ transporters participate in the development of PH by modulating PASMC proliferation, migration, and apoptosis; and Mg²⁺ supplementation attenuates PH through regulation of Mg²⁺ transporters involving the NFATc3 signaling pathway.

Enhanced adhesion and field emission of CuO nanowires synthesized by simply modified thermal oxidation technique

Metal oxide nanowires (NWs) can be easily grown by the thermal oxidation method, but the low adhesion between the NWs and the substrate restricts their practical applications in functional devices. In this work, the conventional hotplate technique is simply modified by introducing one or two stainless steel plates to supply a more stable oxidation environment, which is found to be beneficial to the growth and adhesion of CuO NWs on the Cu substrate. In detail, the Cu foils were heated on the hotplate directly, on one plate over the hotplate, and between two plates over the hotplate at 400 °C in ambient condition. It is found that the NWs obtained between two plates exhibit large length and diameter with moderate density. The sufficient activated oxygen, stable temperature, and proper temperature gradient configuration caused by the two plates accelerate the formation of CuO NWs, and result in the longest NWs with enhanced adhesion. The grain-boundary diffusion and Kirkendall effect are proposed to explain the mechanism of NWs growth and the formation of cracks. The NWs obtained between two plates also showed the best field emission properties, with lowest turn-on field (5.31 V μm(-1)) and threshold field (9.8 V μm(-1)). Excellent field emission properties and enhanced NW-substrate adhesion indicate that these NW arrays could be potentially used as the cathode of field emission displays.

Self-assembly of Au-Ag alloy nanoparticles by thermal annealing

Hemispherical Au-Ag alloy nanoparticles were prepared on 2-inch Si wafer by thermal annealing Au-Ag alloy thin film in protective ambient. The nanoparticles were evenly distributed on the substrate surface. The diameter of the nanoparticles is dependent of the deposition duration of the Au-Ag alloy thin film, and also the separation between the nanoparticles. The minimum and maximum diameters of the nanoparticles obtained so far are about 5 nm and 160 nm, respectively. Experimental evidences indicated that the formation of the hemispherical nanoparticles is due to the surface tensile stressing induced by the lattice expansion.

[Preparation of immobilized metal-chelated affinity membrane and its application to purification of Cu/Zn-superoxide dismutase]

Immobilized metal-chelated affinity membranes were prepared using macropore cellulose filter paper as matrix. The matrix was treated with alkaline, activated with epichlorohydrin and coupled with iminodiacetate sodium, and then Cu2+ was immobilized. Cu/Zn-superoxide dismutase(SOD) was purified with prepared affinity membranes. The special activity of the purified Cu/Zn-SOD was increased 10.7 times from 645 U/mL to 6,882 U/mL. The protein recovery and the activity recovery were 92.3% and 985%, respectively. A new method to prevent the leaking of metal ion was developed and Cu2+ concentration in the effluent was lowered to 86 micrograms/L.