Search

Background Cardiovascular disease (CVD) is a major cause of human mortality worldwide, characterized by its insidious onset, intricate and variable course, and poor prognosis. Early identification and active intervention of potentially critically ill patients is essential to improve their prognosis. Objective To conduct a scoping review of the research on early warning assessment tools for cardiovascular disease risk at home and abroad, summarize and analyze their assessment content and application, ultimately providing reference for the selection of appropriate early warning tools for cardiovascular disease patients in China. Methods CNKI, Wanfang Data, VIP, CBM, PubMed, Web of Science, Cochrane Library, Embase, CINAHL, and Scopus were systematically searched from inception to May 2023. Two investigators independently screened literature and extracted data, analyzed in terms of assessment content, study subjects, validation method, reliability and validity, and predictive efficacy. Results A total of 16 papers were included, comprising 7 papers on the development and validation of assessment tools and 9 papers on the localized application of these tools, involving 20 early warning assessment tools for cardiovascular disease risk. The results of the analysis showed that each assessment tool contained 3 to 17 assessment items, with the most frequently mentioned items of age, systolic blood pressure, respiratory rate, oxygen saturation, heart rate, comorbidities, level of consciousness, and gender. The results of the reliability and validity tests for 2 papers indicated robust reliability and validity, while all other studies lacked reliability and validity evaluations. Ten papers reported the area under the curve (AUC), with values ranging from 0.550 to 0.926 9. Conclusion Diverse early warning assessment tools for cardiovascular disease risk are available, however, their overall quality remains to be improved and there is a lack of specific assessment tools. In the future, it is imperative to conduct further validations of the reliability and validity of the existing tools, and develop localized early warning assessment tools specialized for cardiovascular diseases considering the unique characteristics of the disease, which exhibit robust reliability and validity.

In order to improve the performance of tungsten copper infiltration materials to adapt to the development of advanced propulsion technology, ZrC powder and W powder were adopted as raw materials to prepare ZrC-W framework by pressureless sintering process and the pressure infiltration of ZrC-W framework was conducted by pressure infiltration to prepare ZrC-W-Cu composites. The effect of ZrC content(volume fraction,the same below) on the porosity, compression strength, and microstructure as well as mechanical properties of ZrC-W-Cu composites were investigated. The results show that with the increase of ZrC content, the open porosity of ZrC-W framework increases first and then decreases, reaching the maximum value(29.77%) when ZrC content is 4%. The compressive strength of ZrC-W framework decreases with the increase of ZrC content, for which the compressive strength is lower than that of W framework. With the increase of ZrC content, the Vickers hardness of ZrC-W-Cu composites gradually increases and reaches 3.26 GPa when ZrC content is 15%. The elastic modulus remains unchanged basically, while the fracture toughness first increases and then decreases with the increase of ZrC content. The flexural strength reaches the maximum value up to 1243 MPa when ZrC content is 4%.

Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α -Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MP a.m 1 / 2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

The raw Y2O3 powder was classified and graded based on modified co-sedimentation mathematical model,using the size distribution of W particles as the known condition. Y2O3-W continuous graded materials with the composition distribution index P values of 1.0, 0.7, 0.3 and 0.1 were prepared by co-sedimentation and hot-pressing. The results show that the Y2O3 powder consistent with the design requirements can be obtained by graduation method. The gradient continuity of materials can be verified by microstructure observation and hardness testing.