Background To comprehensively analyze the global level and trends of prevalence, incidence and years lived with disability (YLDs) for low back pain (LBP) from 1990 to 2019 by age, sex and sociodemographic index (SDI). Methods Publicly available modelled data and methods were obtained from the Global Burden of Diseases (GBD) study 2019, and used to evaluate the global burden of LBP through a systematic analysis. Results Globally, the age-standardized prevalence, incidence and YLDs rate of LBP were slightly decreased from 1990 to 2019, but the number of the prevalent cases, incident cases and YLDs had substantially increased, and LBP remains the leading cause of YLDs in 2019 worldwide. The number of prevalent cases was increased with age and peaked at the age of 45–54 years for both sexes, and the global prevalence rate was higher in females than in males and increased with age, peaking at the 80–84 age group in both sexes in 2019. Overall, a positive association between the age-standardized YLD rate and SDI was observed over the past thirty years. At the national revel, the United States, Denmark and Switzerland had the three highest levels of age-standardized prevalence, while Zambia, Zimbabwe and Canada showed the highest increase in the age-standardized prevalence during 1990–2019. Conclusions LBP is a major public health issue globally, and its burden remains high. Increasing population awareness about its risk factors and preventive measures for LBP are needed to reduce the future burden of this condition. The translational potential of this article Due to the high prevalence and heavy burden of LBP globally, it is important to update its epidemiological data. This systematic analysis provides researchers and healthcare policy makers with up-to-date, comprehensive and comparable information on global LBP burden, which is of clinical translational significance.

Moderate or intense low oxygen dilution (MILD) combustion plays a significant role in the mitigation of combustion-generated pollutants and greenhouse gases whilst meeting thermal efficiency needs. However, due to the lack of the fundamental knowledge on this combustion, there is a misconception that MILD combustion should be established by high preheating of the air, which has limited its application. Our research and development on this combustion has been performed for several years. We have found that the requirements for establishing the MILD combustion are more relaxed than previously. It is also revealed that this combustion of different type, i.e., non-premixed, partially premixed and fully premixed, can be achieved by firing various fuels (i.e., gaseous, liquid and solid fuels). It is suggested that the application of the MILD combustion can be expanded significantly. The present review summarizes the progress and recent trend made in the R&D of this combustion and recommends further fundamental studies for improving our knowledge and widening its applications. high temperature air combustion, flameless oxidation, flameless combustion, oxy-fuel combustion Citation: Li P F, Mi J C, Dally B B, et al. Progress and recent trend in MILD combustion.

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