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Fluorescent microspheres exhibit unique emissions at the microscale and have been widely used as probes for immunoassays and advanced micro-sensors. Herein, we report the localized enhancement of the photon upconversion of a single fluorescent microsphere via annular near-field confinement. The single fluorescent microspheres were composed of a 5 μm polystyrene (PS) microsphere coated with upconversion nanoparticles. Ten gold microspheres with a diameter of 5 μm were used for the construction of a "pagoda"-like microcavity. Interestingly, the emission of a single fluorescent microsphere on the "pagoda"-like microcavity was enhanced by tens of times (e.g., 540 nm and 650 nm emissions of Er3+ were increased by 46 times and 40 times, respectively). Theoretical calculations based on the FDTD method confirmed that the confined annular near field overlapped well with the upconversion nanoparticles distributed on the surface of the single fluorescent microsphere so that the emission of the single fluorescent microsphere was significantly enhanced. [ABSTRACT FROM AUTHOR]

Results of previous studies about the acute effects of fine particulate matter (PM2.5) on blood lipids were inconsistent. This study aimed to quantify the short-term effects of PM2.5 on blood lipids and estimate the modifying role of insulin resistance, reflected by the homeostasis model assessment of insulin resistance (HOMA-IR). From September 2019 to January 2020, the study recruited 70 healthy adults from Wuhan University for a total of eight repeated data collections. At each visit, three consecutive days were monitored for personal exposure to PM2.5, and then a physical examination was carried out on the fourth day. The linear mixed-effect models were operated to investigate the impact of PM2.5 over diverse exposure windows on blood lipids. With the median of the HOMA-IR 1.820 as the cut-off point, participants were assigned to two groups for the interaction analyses. We found the overall mean level (standard deviation, SD) of PM2.5 was 38.34 (18.33) μg/m3. Additionally, with a 10 μg/m3 rise in PM2.5, the corresponding largest responses in triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), as well as high-density lipoprotein cholesterol (HDL-C), were −0.91% (95% confidence interval (CI): −1.63%, −0.18%), −0.33% (95% CI: −0.64%, −0.01%,), −0.94% (95% CI: −1.53%, −0.35%), and 0.67% (95% CI: 0.32%, 1.02%), respectively. The interaction analyses revealed that a significantly greater reduction in the four lipids corresponded to PM2.5 exposure when in the group with the lower HOMA-IR (<1.820). In conclusion, short-term PM2.5 exposure over specific time windows among healthy adults was associated with reduced TG, TC, as well as LDL-C levels, and elevated HDL-C. Additionally, the association of PM2.5–lipids may be modulated by insulin resistance. [ABSTRACT FROM AUTHOR]

Evidence on the associations between long-term exposure to ambient air pollutants (including particle with aerodynamic diameter ≤10 μm (PM 10), particle with aerodynamic diameter ≤2.5 μm (PM 2.5), ozone (O 3), nitrogen dioxide (NO 2), and sulfur dioxide (SO 2)) and prevalence of metabolic syndrome (MetS) remains inconclusive. This study aimed to determine the associations based on a case-control study nested in the Wuhan Chronic Disease Cohort study (WCDCS), a population-based study with baseline survey in 2019. A total of 10,253 residents living in Wuhan were recruited. The 3-year average concentrations of main pollutants (PM 10 , PM 2.5 , O 3 , NO 2 , and SO 2) at residences prior to the survey date were estimated to evaluate the long-term exposures. The generalized linear mixed models were used to investigate the changes in MetS prevalence by an IQR increases in each air pollutant exposure concentrations. Interaction effects between air pollutants and demographic, lifestyle, and dietary factors on MetS were evaluated by including an interactive item in the main model. The prevalence of MetS in Wuhan was 9.8%, and the 3-year exposure concentrations of PM 10 , PM 2.5 , O 3 , NO 2 , and SO 2 were 84.1 μg/m3, 50.5 μg/m3, 55.7 μg/m3, 46.0 μg/m3, and 9.4 μg/m3, respectively. Higher PM 10 , PM 2.5 and O 3 exposure concentrations were associated with an elevated MetS prevalence (e.g. an IQR increase in PM 2.5 , OR = 1.193, 95% confidence intervals (95%CIs): 1.028, 1.385; for O 3 , OR = 1.074, 95%CIs: 1.025, 1.124), whereas NO 2 , and SO 2 were negatively or insignificant correlated with odds of Mets (e.g. an IQR increase in NO 2 , OR = 0.865, 95%CIs: 0.795, 0.941). Males, smokers, alcohol drinkers and individuals who intake fruits occasionally exposure to PM 10 and PM 2.5 were found had a higher risk of developing MetS. Long-term exposure to higher concentrations of ambient air pollutants may elevate the prevalence of MetS in populations in Central China. Susceptible individuals especially those with unhealthy lifestyles had a higher risk for MetS. [ABSTRACT FROM AUTHOR]