The microstructure,mechanical properties and corrosion behavior of quaternary degradable Mg−1Zn−0.2Ca−xAg(x=1,2,4 wt.%)alloy wires,intended as anastomotic nails,were investigated.It was found that these Ag-containing ...The microstructure,mechanical properties and corrosion behavior of quaternary degradable Mg−1Zn−0.2Ca−xAg(x=1,2,4 wt.%)alloy wires,intended as anastomotic nails,were investigated.It was found that these Ag-containing alloy wires mainly consist of Mg matrix and Ag17Mg54 phase,characterized by SEM,EDS,XRD and TEM.Tensile and knotting tests results demonstrate the superior mechanical properties of these alloy wires.Especially,Mg−1Zn−0.2Ca−4Ag alloy exhibits the highest mechanical properties,i.e.an ultimate tensile strength of 334 MPa and an elongation of 8.6%.Moreover,with increasing Ag content,the corrosion rates of these alloy wires remarkably increase due to the formation of more micro-galvanic coupling between Mg matrix and Ag17Mg54 phase,shown by mass loss and scanning Kelvin probe force microscopy(SKPFM)results.The present alloy can be completely degraded within 28 d,satisfying the property requirements of anastomotic nails.展开更多
Irrational use of medicines is a major problem worldwide, and it is believed there would be positive correlation between the National Essential Medicines Policies(NEMPs) and the level of rational use of medicines(RUMs...Irrational use of medicines is a major problem worldwide, and it is believed there would be positive correlation between the National Essential Medicines Policies(NEMPs) and the level of rational use of medicines(RUMs). Though there is some early evidence on the NEMPs’ effects on RUMs in China, the evidence is scarce, and conclusions vary. In the present study, we aimed to evaluate the impacts of the NEMPs of China on the RUMs in the primary health care institutions(PHCs). A cross-sectional survey was conducted in 2010. A total of 201 PHCs from six provinces of China were selected, and 39 181 prescriptions were extracted from January to June, 2010. Six indicators were used and tested by independent-samples T test. We found that the average number of drugs per prescription in PHCs with NEMP implementation(the treatment group) was significantly higher than that of the group without NEMP implementation(the control group)(3.37 vs. 2.83, P<0.01). There was no significant difference in the average cost per prescription(81.43 vs. 75.02). The percentage of prescriptions, including an antibiotic(53.40% vs. 36.48%, P<0.01) or an injection(40.54% vs. 27.94%, P<0.01), was higher in the treatment group, and the percentage of drugs prescribed by general name was significantly lower(83.71% vs. 93.11%, P<0.01). For the percentage of drugs prescribed from essential medicines list, the treatment group exhibited the higher ratio(76.12% vs. 53.45%, P<0.01). From this study, the NEMPs were not likely to have a positive impact on RUMs. China still needed efforts to improve the selection, the absence of physicians’ active involvement, and the patients’ habits of irrational medication use.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51671017 and 51971020)the Beijing Municipal Natural Science Foundation,China(2202033)+2 种基金Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,China,the Fundamental Research Funds for the Central Universities,China(FRF-IC-19-015)the Major State Research and Development Program of China(2016YFB0300801)the Opening Research Fund of State Key Laboratory for Advanced Metals and Materials,China(2018-Z04).
文摘The microstructure,mechanical properties and corrosion behavior of quaternary degradable Mg−1Zn−0.2Ca−xAg(x=1,2,4 wt.%)alloy wires,intended as anastomotic nails,were investigated.It was found that these Ag-containing alloy wires mainly consist of Mg matrix and Ag17Mg54 phase,characterized by SEM,EDS,XRD and TEM.Tensile and knotting tests results demonstrate the superior mechanical properties of these alloy wires.Especially,Mg−1Zn−0.2Ca−4Ag alloy exhibits the highest mechanical properties,i.e.an ultimate tensile strength of 334 MPa and an elongation of 8.6%.Moreover,with increasing Ag content,the corrosion rates of these alloy wires remarkably increase due to the formation of more micro-galvanic coupling between Mg matrix and Ag17Mg54 phase,shown by mass loss and scanning Kelvin probe force microscopy(SKPFM)results.The present alloy can be completely degraded within 28 d,satisfying the property requirements of anastomotic nails.
基金National Natural Science Foundation of China(Grant No.71303011,71774005)
文摘Irrational use of medicines is a major problem worldwide, and it is believed there would be positive correlation between the National Essential Medicines Policies(NEMPs) and the level of rational use of medicines(RUMs). Though there is some early evidence on the NEMPs’ effects on RUMs in China, the evidence is scarce, and conclusions vary. In the present study, we aimed to evaluate the impacts of the NEMPs of China on the RUMs in the primary health care institutions(PHCs). A cross-sectional survey was conducted in 2010. A total of 201 PHCs from six provinces of China were selected, and 39 181 prescriptions were extracted from January to June, 2010. Six indicators were used and tested by independent-samples T test. We found that the average number of drugs per prescription in PHCs with NEMP implementation(the treatment group) was significantly higher than that of the group without NEMP implementation(the control group)(3.37 vs. 2.83, P<0.01). There was no significant difference in the average cost per prescription(81.43 vs. 75.02). The percentage of prescriptions, including an antibiotic(53.40% vs. 36.48%, P<0.01) or an injection(40.54% vs. 27.94%, P<0.01), was higher in the treatment group, and the percentage of drugs prescribed by general name was significantly lower(83.71% vs. 93.11%, P<0.01). For the percentage of drugs prescribed from essential medicines list, the treatment group exhibited the higher ratio(76.12% vs. 53.45%, P<0.01). From this study, the NEMPs were not likely to have a positive impact on RUMs. China still needed efforts to improve the selection, the absence of physicians’ active involvement, and the patients’ habits of irrational medication use.
