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[Objective] Soil erosion and its associated carbon loss in an alpine meadow on the Tibetan Plateau were quantitatively analyzed in order to provide a reference for comprehensively evaluating the impact of soil erosion and for implementing effective soil and water conservation measures. [Methods] We used 137Cs tracing technology combined with the results of previous research studies to determine erosion rate and consequent carbon loss for an undisturbed alpine meadow soil on the Tibetan Plateau. [Results] The undisturbed meadow soil exhibited three distinct layers (A, B, and C) of physiochemical properties, and the distribution of 137Cs declined exponentially with increasing soil depth. The recent erosion rate of the alpine meadow soil was about 77—230 t/(km2·yr), and was estimated to result in an average annual soil organic carbon loss of not less than 4.86 t/km2. [Conclusion] Even though the overall soil erosion rate of the alpine meadow on the Tibetan Plateau was low, it’s organic carbon loss due to erosion cannot be underestimated. Both increased human activities and reduced meadow growth due to decreased soil moisture under future global warming are likely to result in further soil degradation and soil organic carbon loss in alpine meadows.

Objective To investigate the anatomic factors influencing the implantation depth (ID) of self-expandable valve during transcatheter aortic valve replacement (TAVR) surgery, and to analyze the impact of ID on the short-term clinical prognosis. Methods Clinical data of 54 patients with severe aortic stenosis who underwent TAVR in our hospital from October 2017 to May 2020 were collected and retrospectively analyzed. The anatomic diameter of aortic root and its ratio to the implanted valve size was measured and calculated, and the depth of the valve implanted was also measured. The patients were assigned into either over-implanted group (>14.8 mm, the highest quartile of ID) or well-implanted group (≤14.8 mm) based on the ID of their valve. The differentiation of anatomical structures was compared between the 2 groups. Additionally, the impacts of ID on the clinical outcomes such as hemodynamics and conduction block were analyzed. Results There were 21 cases of bicuspid aortic valve (BAV) and 33 cases of tricuspid aortic valve (TAV), and the ID of valve was 0~21 mm, with a median of 11.6 mm. Among the BAV patients, the average diameter of sinotubular junction (STJ) was significantly larger in the over-implanted group than the well-implanted group (36.06±2.29 vs 29.69±2.55 mm, P=0.001). As for the TAV patients, the over-implanted group had a higher proportion of large prosthesis implantation (100.0% vs 26.9%, P=0.025), and a smaller ratio of the length of the left ventricular output tract to the bottom diameter of the valve (0.99±0.03 vs 1.12±0.15, P=0.021) when compared with the well-implanted group. Postoperative mortality was comparable between the 2 groups (4.88% vs 15.38%, P=0.242). However, the incidence of being converted to open surgery was higher in the over-implanted group than the other group (15.4% vs 0%, P=0.055). In 1 week after TAVR, there were no statistical differences in the mean aortic valve gradient, maximum velocity, permanent pacemaker implantation rate, moderate or severe paravalvular leakage, or new-onset left bundle branch block (LBBB) between the 2 groups (P>0.05), whereas the incidence of new-onset LBBB (50.0% vs 13.3%, P=0.044) and paravalvular leakage (33.3% vs 0%, P=0.009) were higher in the over-implanted group on the 30th day. The early safety was inferior in the over-implanted group (69.2% vs 95.1%, P=0.025). Conclusion The anatomical structure of the aortic root and its ratio to the size of the implanted valve have a certain effect on the implantation depth of self-expandable prosthesis. The BAVs patients with greater STJ as well as those TAVs patients treated with larger size valve may be both correlated with increased risks of deep implantation. Over implantation of the valve may increase the risk of new-onset LBBB and moderate or severe paravalvular leakage in 1 month after operation, and thus compromise the early safety.

Driven by the digitization and informatization of contemporary society, electrical sensors are developing toward minimal structure, intelligent function, and high detection resolution. Single‐molecule electrical measurement techniques have been proven to be capable of label‐free molecular recognition and detection, which opens a new strategy for the design of efficient single‐molecule detection sensors. In this review, we outline the main advances and potentials of single‐molecule electronics for qualitative identification and recognition assays at the single‐molecule level. Strategies for single‐molecule electro‐sensing and its main applications are reviewed, mainly in the detection of ions, small molecules, oligomers, genetic materials, and proteins. This review summarizes the remaining challenges in the current development of single‐molecule electrical sensing and presents some potential perspectives for this field. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing requirement for rapid and cost-effective additive manufacturing solutions for copper alloys with favorable mechanical properties. In this research, laser–direct current arc hybrid additive manufacturing (LAHAM) was employed to fabricate Cu-Cr-Zr alloy. By way of multi-scale characterization including SEM, EBSD and TEM, the effect of scanning speed on the microstructure was systematically investigated in detail. Moreover, an evaluation of mechanical properties was carried out. The results indicated that columnar grains grew across layers with the growth direction tending to the center of the molten pool. When the scanning speed increased from 250 mm/min to 350 mm/min, the proportion of high-angle grain boundaries exceeded 69% and reached a maximum of 79% at 300 mm/min. A large amount of Cr phase was precipitated from the Cu matrix. Both submicron and nanoscale Cr precipitates were observed. Statistically, the area proportion of Cr precipitates was up to 26.3% at 300 mm/min. The changes of heat input and remelting effects were the main reasons for the change in the precipitate level. As a result, the mechanical properties of the Cu-Cr-Zr alloy were enhanced via precipitation strengthening. When the scanning speed was 250 mm/min, the Cu-Cr-Zr alloy sample exhibited an ultimate tensile strength of 311.3 ± 7.8 MPa with an elongation of 38.6 ± 5.6%. [ABSTRACT FROM AUTHOR]