Long-term spatial distribution and implication of black and brown carbon in the Tibetan Plateau.

Black carbon (BC) and brown carbon (BrC) over the high-altitude Tibetan Plateau (TP) can significantly influence regional and global climate change as well as glacial melting. However, obtaining plateau-scale in situ observations is challenging due to its high altitude. By integrating reanalysis data with on-site measurements, the spatial distribution of BC and BrC can be accurately estimated using the random forest algorithm (RF). In our study, the on-site observations of BC and BrC were successively conducted at four sites from 2018 to 2021. Ground-level BC and BrC concentrations were then obtained at a spatial resolution of 0.25° × 0.25° for three periods (including Periods-1980, 2000, and 2020) using RF and multi-source data. The highest annual concentrations of BC (1363.9 ± 338.7 ng/m3) and BrC (372.1 ± 96.2 ng/m3) were observed during Period-2000. BC contributed a dominant proportion of carbonaceous aerosol, with concentrations 3-4 times higher than those of BrC across the three periods. The ratios of BrC to BC decreased from Period-1980 to Period-2020, indicating the increasing importance of BC over the TP. Spatial distributions of plateau-scale BC and BrC concentrations showed heightened levels in the southeastern TP, particularly during Period-2000. These findings significantly enhance our understanding of the spatio-temporal distribution of light-absorbing carbonaceous aerosol over the TP.

Exercise Reduces Insulin Resistance in Type 2 Diabetes Mellitus via Mediating the lncRNA MALAT1/MicroRNA-382-3p/Resistin Axis.

Insulin resistance (IR) is the primary pathological mechanism underlying type 2 diabetes mellitus (T2DM). Here, the study aimed to ascertain whether and how exercise mediates IR in T2DM. An in vivo mouse model of high-fat diet-induced IR and an in vitro high-glucose-induced IR model were constructed. High long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression was detected in T2MD and was positively correlated with HOMA-IR and resistin levels. Then, short hairpin RNA targeting MALAT1 (sh-MALAT1) or pcDNA-MALAT1 was delivered into human umbilical vein endothelial cells (HUVECs) to knock down or upregulate its expression, respectively. Silencing of MALAT1 resulted in reduced levels of resistin, Ang II, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), endothelin-1 (ET-1), and p-insulin receptor substrate-1 (p-IRS)/ISR-1, and decreased cell migration, as well as enhanced glucose uptake and levels of nitric oxide (NO) and p-Akt/Akt. In the IR mouse model, exercise was observed to downregulate MALAT1 to reduce resistin, whereby exercise reduced homeostatic model assessment-insulin resistance (HOMA-IR). Besides, exercise also elevated microRNA-382-3p (miR-382-3p) expression in the serum of IR mice. Dual-luciferase reporter and RNA binding protein immunoprecipitation (RIP) assays identified that MALAT1 could bind to miR-382-3p to upregulate resistin. Collectively, the key observations of the study provide evidence that inhibition of MALAT1 elevates miR-382-3p to repress resistin, which consequently underlies the mechanism of exercise protecting against IR, highlighting a direction for T2DM therapy development.

Aerobic Exercise Prevents Insulin Resistance Through the Regulation of miR-492/Resistin Axis in Aortic Endothelium.

Previously, we found that miR-492 delayed the progression of atherosclerosis (AS) by acting as an up-stream regulator of resistin. Therefore, we hypothesized that the anti-atherogenic effects of exercise are related to miR-492-mediated downregulation of resistin and repair of endothelial injury. In this study, we investigated the effects of the miR-492/resistin axis on improving endothelial injury in ApoE-/- mice (ApoE-deficient/knockout in C57BL/6 mice) through swimming exercises. Our results showed that the severity of AS and insulin resistance (IR) in these mice were significantly reduced by swimming exercises. In addition, miR-492 expression in the aortic endothelium of ApoE-/- mice was decreased, in addition to increased levels of resistin. Interestingly, swimming exercises increased miR-492 expression while decreasing that of resistin. Taken together, swimming exercises delayed the progression of AS, possibly by upregulating miR-492 and downregulating resistin in aortic endothelium. Therefore, exercises modulated glucose and lipid metabolism, alleviated endothelial IR, and repaired endothelial injury.

[Comparison of Characteristics and Reactive Oxidative Species of PM2.5 in Xi'an, China During Haze and Clean Days].

PM2.5 samples were collected in Xi'an, China during haze(2015-11-30-2015-12-9) and clean days(2016-01-13-2016-01-22). PM2.5 mass, organic carbon(OC), elemental carbon(EC), and water-soluble ions(i.e., NH4+, NO3-, and SO42-) were measured to investigate the characteristics of the two typical pollution processes. The result showed that PM2.5 masses were(170±47.5) µg·m-3 and(48.6±17.9) µg·m-3 for the haze and clean days, respectively, with the haze accompanied by low visibility, high humidity, calm wind, and other adverse weather conditions. The secondary inorganic aerosol(SIA) including NH4+, NO3-, and SO42- accounted for 49.8%±13.1% and 19.4%±5.95% of the PM2.5 mass for the haze and clean days, respectively. sulfur and nitrogen oxidation ratios(SOR and NOR) on haze days were 0.282±0.157 and 0.269±0.124, respectively, which were much higher than those measured on the clean days(0.189±0.057 and 0.077±0.046). The average concentration of secondary organic carbon(SOC) for the haze days(6.22±3.87) µg·m-3 was 5 times of that measured in the clean days(1.44±1.63) µg·m-3. Secondary pollution and adverse weather conditions were the main reasons for the heavy haze. Finally, the level of particulate-Reactive Oxygen Species(ROS)was measured by the 2',7'-dichlorofluorescin diacetate(2',7'-DCFH) fluorescence method, and the average ROS concentration (as H2O2) was(4.99±1.54) nmol·m-3 during haze days and(0.492±0.356) nmol·m-3 during clean days. Accumulation effect and secondary oxidation process may be the main reasons for the increase of ROS concentration under the heavy haze conditions in Xi'an. Positive correlations(P<0.05) between the concentrations of ROS and the ions of NO3- and SO42- indicated that ROS may participate in secondary oxidation process of SIA.

[Pollution Characteristics and Sources of Carbonaceous Aerosol in PM2.5 During Winter in Guanzhong Area].

To study the characteristics and sources of carbonaceous aerosol in PM2.5 during winter in Guanzhong area, PM2.5 samples were collected from December 2012 to February 2013 in Xi'an, Baoji, Weinan and Qinling, and then organic carbon (OC) and elemental carbon (EC) were analyzed following the thermal/optical reflection protocol. The average concentrations of OC in the four sites were 47.8, 45.8, 31.2 and 37.0 microg x m(-3), respectively, while EC concentrations were 8.5, 6.7, 7.6 and 5.7 microg x m(-3), respectively. Total carbonaceous aerosol (TCA) accounted for 36.4%, 46.2%, 36.9% and 33.4% of PM2.5, respectively. OC was strongly correlated with EC in Xi'an (R2 = 0.93) and Qinling (R2 = 0.91), while weakly correlated in Baoji (R2 = 0.58) and Weinan (R2 = 0.62), which indicated that OC and EC had more similar sources or higher mixing degree in the former two sites. All OC/EC ratios exceeded 2.0, which indicated the formation of secondary organic carbon (SOC). In Xi'an, Baoji, Weinan and Qinling, SOC accounted for 21.6%, 40.3%, 23.2% and 27.8% of OC, respectively. Positive matrix factorization (PMF) was used to analyze the sources of carbonaceous aerosol and four sources were obtained. Coal burning was the major source, contributing 45.3%-47.9% in Guanzhong area. Gasoline vehicle and biomass burning were the minor sources, contributing 26.1%-33.1% and 14.3%-20.1% respectively. In addition, diesel vehicle also had some contribution to carbonaceous aerosol.

Cardiovascular autonomic neuropathy in patients with type 2 diabetes.

AIMS/INTRODUCTION: Heart rate recovery (HRR) after exercise is considered to be a new index of autonomic dysfunction associated with cardiovascular disease and mortality. The present study aimed to investigate the risk factors of HRR and the effects of exercise on the abnormal HRR in type 2 diabetes. MATERIALS AND METHODS: A total of 123 type 2 diabetes patients were recruited, and the oral glucose tolerance test and exercise test were carried out to analyze the risk factors associated with abnormal HRR. Among these patients, 42 patients with abnormal HRR were further randomized to either the conventional therapy group (CT group; n = 20) or the intensive therapy group (IT group; n = 22). The CT group patients underwent metformin and diet control, whereas the IT group additionally underwent a combined moderate intensity aerobic and resistance training three times per week for 12 weeks. The results of blood sample analysis and HRR were recorded before and after the training. RESULTS: Abnormal HRR was related to fasting blood glucose, glycosylated hemoglobin, low-density lipoprotein cholesterol, and resting and maximum heart rates (P < 0.05 for both). After training, the IT group had significantly lower levels of fasting blood glucose, glycosylated hemoglobin and resting heart rate than the CT group (all P < 0.01 or P < 0.005). Significant improvement in HRR and metabolic equivalents was observed in the IT group compared with the CT group (P < 0.05). CONCLUSIONS: These data suggested that combined aerobic and resistance training improved cardiac autonomic dysfunction as measured by HRR in type 2 diabetes patients. This might be due to better improvement of glycemic control, resting heart rate and physical fitness.

The rural carbonaceous aerosols in coarse, fine, and ultrafine particles during haze pollution in northwestern China.

The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 µm, particulate matter with an aerodynamic diameter less than 10 µm), fine particle (PM2.5: Dp ≤ 2.5 µm), and ultrafine particle (PM0.133: Dp ≤ 0.133 µm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM2.5 contributed a large fraction in PM10. OC (organic carbon) accounted for 33, 41, and 62 % of PM10, PM2.5, and PM0.133, and those were 2, 2.4, and 0.4 % for EC (elemental carbon) in a rural area, respectively. OC3 was more abundant than other organic carbon fractions in three PMs, and char dominated EC in PM10 and PM2.5 while soot dominated EC in PM0.133. The present study inferred that K(+), OP, and OC3 are good biomass burning tracers for rural PM10 and PM2.5, but not for PM0.133 during haze pollution. Our results suggest that biomass burning is likely to be an important contributor to rural PMs in northwestern China. It is necessary to establish biomass burning control policies for the mitigation of severe haze pollution in a rural area.

[Chemical Compositions in PM2.5 and Its Impact on Visibility in Summer in Pearl River Delta, China].

Aerosol samples of PM2.5 were collected simultaneously at 6 sites from five cities (Guangzhou urban, Conghua (suburban of Guangzhou), Foshan, Dongguan, Shenzhen and Zhubai) in Pearl River Delta region during the summer of 2010. The concentrations of organic carbon (OC), elemental carbon (EC) and water-soluble ions were determined by thermal/optical carbon analyzer and ion chromatography, respectively. The characteristics of PM2, OC, EC and ions, spatial distribution were discussed. Moreover, ambient light extinction coefficients were reconstructed by IMPROVE formula. The results showed that spatial distribution characteristics of PM2.5. and its chemical compositions were obviously different. The PM2.5 in Guangzhou, Foshan and Dongguan were higher than those in Zhuhai and Shenzhen. The contributions of (NH4)2SO4, OM, EC and NH4NO3 to ambient light extinction coefficient were 39%, 31%, 12% and 13%, respectively.

Effects of combined aerobic and resistance training on the glycolipid metabolism and inflammation levels in type 2 diabetes mellitus.

[Purpose] To investigate the effects of combined aerobic and resistance training on glycolipid metabolism and inflammation levels in type 2 diabetes mellitus patients. [Subjects and Methods] Forty-two diabetes patients were randomized to the conventional therapy group (n = 20) or intensive therapy group (n = 22). The control group contained 20 healthy people. The conventional therapy group received routine drug therapy and diet control, while the intensive therapy group additionally underwent combined aerobic and resistance training for 12 weeks. The oral glucose tolerance test and cardiopulmonary exercise testing were performed. Toll-like receptor 4 and NF-κBp65 protein and mRNA expressions were determined by qPCR and western blotting. ELISA was used to determine the expression levels of interleukin-18, interleukin-33, pentraxin-related protein 3, and human cartilage glycoprotein 39. [Results] After exercise training, the intensive therapy group had significantly lower postprandial blood glucose, postprandial insulin, and glycated hemoglobin level and insulin resistance index than the conventional therapy group. The intensive therapy group had significantly lower toll-like receptor 4 and NF-κBp65 protein and mRNA expressions, and serum interleukin-18 levels but significantly higher serum interleukin-33 levels. [Conclusion] Combined aerobic and resistance training can improve glycolipid metabolism and reduce low-grade inflammation in patients with diabetes mellitus patients.

Characterization and seasonal variations of levoglucosan in fine particulate matter in Xi'an, China.

PM2.5 (particulate matter with an aerodynamic diameter <2.5 microm) samples (n = 58) collected every sixth day in Xi'an, China, from 5 July 2008 to 27 June 2009 are analyzed for levoglucosan (1,6-anhydro-beta-D-glucopyranose) to evaluate the impacts of biomass combustion on ambient concentrations. Twenty-four-hour levoglucosan concentrations displayed clear summer minima and winter maxima that ranged from 46 to 1889 ng m(-3), with an average of 428 +/- 399 ng m(-3). Besides agricultural burning, biomass/biofuel combustion for household heating with straws and branches appears to be of regional importance during the heating season in northwestern China. Good correlations (0.70 < R < 0.91) were found between levoglucosan relative to water- soluble K+, Cl-, organic carbon (OC), elemental carbon (EC), and glyoxal. The highest levoglucosan/OC ratio of2.3% wasfound in winter, followed by autumn (1.5%). Biomass burning contributed to 5.1-43.8% of OC (with an average of 17.6 +/- 8.4%).

Comparison and implications of PM2.5 carbon fractions in different environments.

The concentrations of PM2.5 carbon fractions in rural, urban, tunnel and remote environments were measured using the IMPROVE thermal optical reflectance (TOR) method. The highest OC1 and EC1 concentrations were found for tunnel samples, while the highest OC2, OC3, and OC4 concentrations were observed for urban winter samples, respectively. The lowest levels of most carbon fractions were found for remote samples. The percentage contributions of carbon fractions to total carbon (TC) were characterized by one peak (at rural and remote sites) and two peaks (at urban and tunnel sites) with different carbon fractions, respectively. The abundance of char in tunnel and urban environments was observed, which might partly be due to traffic-related tire-wear. Various percentages of optically scattering OC and absorbing EC fractions to TC were found in the four different environments. In addition, the contribution of heating carbon fractions (char and soot) indicated various warming effects per unit mass of TC. The ratios of OC/EC and char/soot at the sites were shown to be source indicators. The investigation of carbon fractions at different sites may provide some information for improving model parameters in estimating their radiative effects.

[Characterization of chemical compositions in PM2.5 and its impact on hazy weather during 16th Asian Games in Guangzhou].

Aerosol samples for PM2.5 were collected days and nights from 4 to 30 November 2010 in Guangzhou. The concentrations of organic carbon, element carbon, and water-solubility ions of all particle samples were determined by thermal/optical carbon analyzer and ion chromatography, respectively. In-situ online PM,, mass concentrations, light extinction coefficients (bext), and selected meteorological parameters for this period were also measured. Temporal variation of PM,, mass concentrations and its relationship with bext were discussed, and bext was reconstructed by revised IMPROVE formula. The results showed that the average mass concentration ol PM2.5 was (77.0 +/- 24.4) microg.m-3 during the Asian Games period, which was 27.8% lower than that of the period before Asian Games. PM2.5 and relative humidity were the dominant factors contributing to hazy weather. The average value of bx, was 418 Mm-1 during the Asian Games period, which was 28.3% lower than that of the period before Asian Games. The major contributors to bext included (NH4) 2SO4, POM, and LAC, which accounted for 87.0% of bext during the Asian Games period. A series of stringent air quality control measures were implemented by the Guangzhou Municipal Government and other cooperative cities, which greatly alleviated the hazy weathers in Guangzhou urban area during the Asian Games period.

[Day-night variation of carbonaceous aerosols in PM10 during winter and spring over Xi'an].

The purpose of this study was to investigate the day-night variation of carbonaceous aerosols in PM10 during spring and winter over Xi'an. PM10 samples were collected during 19 Dec 2006 to 21 Jan 2007 (Winter) and 1 Apr 2007 to 30 Apr 2007 (Spring). Organic carbon (OC) and elemental carbon (EC) concentrations were measured using thermal-optical method. PM10, OC, and EC concentrations in winter were 455.0, 62.4, and 7.5 microg/m3 during daytime, and 448.7, 66.1, and 6.9 microg/m3 for nighttime, respectively, while in spring were 397.9, 26.7, and 6.9 microg/m3 for daytime, and 362.1, 31.9, and 8.6 microg/m3 for nighttime. The correlation coefficient of OC and EC during daytime in winter was 0.44, while a strong relationship between OC and EC was observed in spring daytime, indicating that the emission sources of carbonaceous aerosol in winter were more complicated than those in spring. Due to high OC levels and the weaker dispersal ability of atmosphere, the mean concentrations of SOC during winter (8.9 and 10.2 microg/m3 at daytime and nighttime) were much higher than those in spring (2.8 and 3.4 microg/m3). Factor analysis on the eight carbon fraction indicated that coal combustion and biomass burning were the major sources for carbonaceous aerosol in winter, while vehicle exhaust played an important role in spring.