Magnetic detection under high pressures using designed silicon vacancy centres in silicon carbide.

Pressure-induced magnetic phase transitions are attracting interest as a means to detect superconducting behaviour at high pressures in diamond anvil cells, but determining the local magnetic properties of samples is a challenge due to the small volumes of sample chambers. Optically detected magnetic resonance of nitrogen vacancy centres in diamond has recently been used for the in situ detection of pressure-induced phase transitions. However, owing to their four orientation axes and temperature-dependent zero-field splitting, interpreting these optically detected magnetic resonance spectra remains challenging. Here we study the optical and spin properties of implanted silicon vacancy defects in 4H-silicon carbide that exhibit single-axis and temperature-independent zero-field splitting. Using this technique, we observe the magnetic phase transition of Nd2Fe14B at about 7 GPa and map the critical temperature-pressure phase diagram of the superconductor YBa2Cu3O6.6. These results highlight the potential of silicon vacancy-based quantum sensors for in situ magnetic detection at high pressures.

Spatiotemporal Distribution Characteristics and Driving Forces of PM2.5 in Three Urban Agglomerations of the Yangtze River Economic Belt.

As part of one of the five major national development strategies, the Yangtze River Economic Belt (YREB), including the three national-level urban agglomerations (the Cheng-Yu urban agglomeration (CY-UA), the Yangtze River Middle-Reach urban agglomeration (YRMR-UA), and the Yangtze River Delta urban agglomeration (YRD-UA)), plays an important role in China's urban development and economic construction. However, the rapid economic growth of the past decades has caused frequent regional air pollution incidents, as indicated by high levels of fine particulate matter (PM2.5). Therefore, a driving force factor analysis based on the PM2.5 of the whole area would provide more information. This paper focuses on the three urban agglomerations in the YREB and uses exploratory data analysis and geostatistics methods to describe the spatiotemporal distribution patterns of air quality based on long-term PM2.5 series data from 2015 to 2018. First, the main driving factor of the spatial stratified heterogeneity of PM2.5 was determined through the Geodetector model, and then the influence mechanism of the factors with strong explanatory power was extrapolated using the Multiscale Geographically Weighted Regression (MGWR) models. The results showed that the number of enterprises, social public vehicles, total precipitation, wind speed, and green coverage in the built-up area had the most significant impacts on the distribution of PM2.5. The regression by MGWR was found to be more efficient than that by traditional Geographically Weighted Regression (GWR), further showing that the main factors varied significantly among the three urban agglomerations in affecting the special and temporal features.

Feasibility of DDD Pacemaker Implantation Under EnSite Systerm Guidance With Micro X-ray / 中国循环杂志

Objective: To explore the feasibility of DDD pacemaker implantation under EnSite system guidance with micro X-ray. Methods: DDD pacemaker implantation under EnSite system guidance with micro X-ray was performed in 5 special patients who needed cardiac pacing while should be avoid X-ray exposure. Results: All 5 patients were smoothly finished DDD pacemaker implantation, no wire dislocation or perforation occurred after the operation. The cumulative skin radiation dose was (2.20±0.45) mGy, operative X-ray exposure time was (11.60±2.07) s and the operation time was (58.40±4.04) min. Conclusion: DDD pacemaker implantation under EnSite system guidance with micro X-ray was safe and feasible.

Long-term outcome of percutaneous balloon mitral valvuloplasty in patients with rheumatic mitral valve stenosis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the outcome of percutaneous balloon mitral valvuloplasty (PBMV) in patients with rheumatic mitral valve stenosis.</p><p><b>METHODS</b>From April 1992 to November 2008, 1768 patients underwent PBMV in our hospital.Clinical and echocardiographic follow up data were analyzed in 426 patients from April 1992 to August 1998. Left atrial pressure and the mitral valve gradient (MVG) were measured before and immediately after PBMV in all patients.</p><p><b>RESULTS</b>PBMV was successful in 1748 out of 1768 patients (98.86%). Left atrial pressure decreased from (38 +/- 7) mm Hg (1 mm Hg = 0.133 kPa) to (12 +/- 4) mm Hg (P < 0.001), MVG decreased from (28 +/- 6) mm Hg to (8 +/- 3) mm Hg (P < 0.001) and the area of the mitral valve increased from (0.98 +/- 0.26) cm(2) to (1.97 +/- 0.39) cm(2) (P < 0.001) post PBMV. The main complications included death (n = 2), acute pericardial effusion (n = 1), severe mitral regurgitation (n = 12), cerebral embolism (n = 2) and pulmonary edema (n = 1). Ten years follow up was finished in 426 patients and 288 patients (67.6%) were still in NYHA class Ior II without mitral valve replace operation or repeated PBMV, restenosis was evidenced in 140 patients (33.3%) and 31 patients dead (7.5%).</p><p><b>CONCLUSION</b>PBMV was an effective therapy option for patients with rheumatic mitral valve stenosis.</p>