按照目前的发展趋势,全球将难以实现世界卫生大会(World Health Assembly)制定的2025年非传染性疾病(non-communicable diseases, NCDs)防控目标,包括“遏制糖尿病与肥胖患病率上升趋势”和“以2010年为基准年,将心血管疾病、癌症、糖...按照目前的发展趋势,全球将难以实现世界卫生大会(World Health Assembly)制定的2025年非传染性疾病(non-communicable diseases, NCDs)防控目标,包括“遏制糖尿病与肥胖患病率上升趋势”和“以2010年为基准年,将心血管疾病、癌症、糖尿病或慢性呼吸系统疾病导致的总体过早死亡率相对降低25%”(世卫组织,2013年)。全球亦难以实现2015年联合国可持续发展峰会确立的可持续发展目标,即到2030年“通过预防和治疗将NCDs导致的过早死亡率减少三分之一”(联合国,2015年)。多种风险因素加剧NCD患病风险,包括吸烟、缺乏体育锻炼、不良饮食和超重等。这些因素导致全球半数以上NCDs过早死亡(2021年约1 070万例)。其中160万例(15%)过早死亡归因于高身体质量指数(body mass index, BMI*,衡量超重的替代指标)(全球疾病负担研究,global burden of disease, GBD, 2024年)。在2型糖尿病相关过早死亡中,该比例攀升至55%。除了导致过早死亡的全球负担,还有大量患者虽存活但饱受NCDs带来的健康问题困扰。2021年,成人因NCDs在已知风险因素影响下累计损失1.611亿健康寿命年,其中4 430万(27%)健康寿命年损失归因于高BMI(GBD,2024年)。有证据表明,除非采取强有力的政策干预,否则降低成人高BMI患病率的目标将难以实现。根据当前趋势,到2030年,高BMI将影响近30亿成人(约占全球成年人口50%)。这一数值显著高于2015年可持续发展目标设定的低于20亿(40%)和2010年世卫组织NCD防控目标基准年的16亿(36%)。高BMI的可能性随着年龄增长而增加,因此到65岁或70岁时,大部分人群将经历超重或肥胖。2022年数据显示,全球200个国家中,147个国家的成人终身高BMI风险超过52%,其中62个国家该风险超过80%。以BMI≥35 kg/m~2为阈值,全球多数国家超过10%的成人一生中都会超过该值。根据2022年数据,在近五分之一国家中,超过20%的成人一生中早晚会超过该值。按当前发展趋势,高BMI人数预计将持续上升,中等收入国家尤为显著。这是对需要接受医疗干预的肥胖人群比例的保守估计。各国应对成人高BMI的能力可以通过以下因素评估:国家卫生系统提供肥胖和NCDs治疗的能力、监测实现国家目标进展的能力以及实施全国性政策和行动以预防全民体质量增加的能力。最新数据通过8个“卫生系统准备度”指标表明,仅有13个国家在全部8个准备度指标上具备能力(包括监测和引导)。在5项肥胖预防政策指标中,没有任何国家将5项政策和行动全部落实。总体而言,只有1个国家(汤加)在13项综合指标中满足12项,另有5个国家(墨西哥、印度、英国、芬兰和马来西亚)满足11项。67个国家在13项指标中仅有1项或没有任何一项达标。多数国家的医疗体系尚未做好充分应对肥胖的准备,且肥胖防控政策仍显不足。展开更多
The superplasticity of Al-6Mg-0.4Mn-0.25Sc-0.12Zr and Al-6Mg-0.4Mn-0.25Er-0.12Zr(mass fraction,%)alloys sheet was investigated,and the effect of Sc and Er was discussed.The results show that the superplastic ductiliti...The superplasticity of Al-6Mg-0.4Mn-0.25Sc-0.12Zr and Al-6Mg-0.4Mn-0.25Er-0.12Zr(mass fraction,%)alloys sheet was investigated,and the effect of Sc and Er was discussed.The results show that the superplastic ductilities of Al-Mg-Mn-Sc-Zr alloy was higher than that of Al-Mg-Mn-Er-Zr alloy at a wide temperature range of 400-540°C and high strain rate range of1.67×10-4-1.67×10-1 s-1.A maximum elongation 673%is obtained at 520°C and 1.67×10-3 s-1 in the Sc-containing alloy;while the Er-containing alloy only gets a maximum elongation 253%at 520°C and 1.67×10-3 s-1.Moreover,the average stress exponent of Sc-containing alloy is about 2.84,which is smaller than that of Er-containing alloy(3.64).Besides,the activation energies of the Sc-containing and Er-containing alloy are 84.8 k J/mol and 87.2 k J/mol,respectively.It is indicated that grain boundary sliding is the dominant mechanism during tensile deformation.According to microstructure examination,the better superplasticity of Sc-containing alloy may be attributed to the presence of Al3_(Sc,Zr)dispersoids,which can inhibit recrystallization and grain growth effectively.展开更多
基金Project(2014M552149) supported by the China Postdoctoral Science FoundationProject(CX2016B041) supported by the Hunan Provincial Innovation Foundation For Postgraduate,ChinaProject(CSUZC201614) supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘The superplasticity of Al-6Mg-0.4Mn-0.25Sc-0.12Zr and Al-6Mg-0.4Mn-0.25Er-0.12Zr(mass fraction,%)alloys sheet was investigated,and the effect of Sc and Er was discussed.The results show that the superplastic ductilities of Al-Mg-Mn-Sc-Zr alloy was higher than that of Al-Mg-Mn-Er-Zr alloy at a wide temperature range of 400-540°C and high strain rate range of1.67×10-4-1.67×10-1 s-1.A maximum elongation 673%is obtained at 520°C and 1.67×10-3 s-1 in the Sc-containing alloy;while the Er-containing alloy only gets a maximum elongation 253%at 520°C and 1.67×10-3 s-1.Moreover,the average stress exponent of Sc-containing alloy is about 2.84,which is smaller than that of Er-containing alloy(3.64).Besides,the activation energies of the Sc-containing and Er-containing alloy are 84.8 k J/mol and 87.2 k J/mol,respectively.It is indicated that grain boundary sliding is the dominant mechanism during tensile deformation.According to microstructure examination,the better superplasticity of Sc-containing alloy may be attributed to the presence of Al3_(Sc,Zr)dispersoids,which can inhibit recrystallization and grain growth effectively.
