[Differences of Three Methods in Determining Ozone Sensitivity in Nanjing].

In recent years， ozone （O3） has become an increasingly important air pollutant in China. Identifying the sensitivity of O3 to the precursors volatile organic compounds （VOCs） and nitrogen oxides （NOx） can help make effective abatement strategies. This study compared three methods for determining O3-VOCs-NOx sensitivity： simulated photochemical indicator values and sensitivity coefficients derived from a three-dimensional air quality model and an observation-based model （OBM）， with a case study involving an O3 pollution event that occurred in Nanjing in late July 2017. The results showed that O3 sensitivity based on the photochemical indicator and sensitivity coefficients demonstrated similar spatial variations （over 50% of the grid cells of Nanjing exhibiting identical O3 sensitivity）. However， sensitivity coefficients identified a larger number of areas within a transitional O3 sensitivity regime， as opposed to the VOCs- or NOx-limited regime identified by the photochemical indicator. The determination of the latter was affected by the adopted threshold values. The OBM relied on the quality of the observational data. For example， positive biases in observed NO2 could lead to an underestimation of O3 sensitivity to NOx with the OBM. During the high pollution period， the three methods exhibited significant disparities. The photochemical indicator tended to suggest the VOCs-limited condition， whereas the OBM and sensitivity coefficients indicated the NOx-limited or transitional regimes.

[Seasonal Variations, Size Distributions, and Sources of Chemical Components of Submicron Particulate Matter in Nanjing].

Size-segregated particulate matter (PM) samples were collected in different seasons from 2016 to 2017 at the Xianlin Campus of Nanjing University. Mass concentrations of water-soluble inorganic ions, carbonaceous components, and elements were analyzed for PM with an aerodynamic diameter ≤ 1.1 µm (PM1.1; <0.4 µm, 0.4-0.7 µm, and 0.7-1.1 µm). The results showed that PM1.1, OC, NO3-, SO42-, and NH4+ exhibited higher ambient levels in fall-winter than those in spring-summer, which was attributed to the changes in local diffusion conditions, evaporation, and decomposition of non-refractory components. Elemental carbon (EC) reached its maximum concentration[(1.87±0.98) µg·m-3]in spring due to the increase in industrial and road dust resuspension. According to the characteristic ratio between bulk components, the anions in PM1.1 were dominated by NO3-, SO42-, and Cl- in Nanjing, and the carbonaceous components were mainly from fossil fuel combustions and associated aging processes. As the ambient temperature increased, the size distributions of thermo-unstable components including NH4+, NO3-, and OC shifted towards finer particles, whereas EC became more enriched in coarse particles, possibly due to the increase in emission intensity of motor vehicles and fugitive dust contributions. Since high relative humidity (>70%) is often accompanied by high temperature (>20℃) and improved diffusion conditions, a relative humidity of 60%-70% was more conducive to the formation of secondary inorganic ions in PM1.1. Source apportionment results based on the speciation data of PM1.1 showed that secondary formation processes[(66.6±18.3)%]and dust resuspension[(16.8±14.8)%]were the main contributors to PM1.1 in Nanjing, and further control of the emissions of gaseous precursors and dust is necessary.

[Variations in PM2.5 Composition and Sources During 2020-2021 COVID-19 Epidemic Periods in Nanjing].

To understand the changes in chemical composition and sources of PM2.5 under the extreme reduction background during the COVID-19 epidemic periods in Nanjing, hourly observation results of PM2.5 components (water-soluble inorganic ions, carbonaceous components, and inorganic elements) of two epidemic events from January to March 2020 and June to August 2021 were analyzed. In comparison to that during pre-epidemic periods, the concentration of NO3- during the two epidemic control periods decreased by 52.9% and 43.0%, respectively, which was larger than the decreases in NH4+(46.4% and 31.6%) and SO42-(33.8% and 16.5%). Since the observation site was located close to a main road, the decrease in elemental carbon (EC, 35.4% and 20.6%) was higher than that in organic carbon (OC, 11.1% and 16.2%). In reference to the variations in the characteristic ratios of the bulk components mentioned above, the epidemic control showed a more substantial influence on traffic emissions than industrial activities. The concentration time series of PM2.5 major components over the epidemic periods indicated that NOx from local traffic emissions had substantial contributions to the formation of NO3-, which led to local short-term PM2.5 pollution. In addition, the positive matrix factorization (PMF) model was used to analyze the hourly observation data of PM2.5 components. The seven identified factors were linked with metallurgy, firework and firecracker combustions, road traffic emissions, coal combustion, dust resuspension, secondary sulfate, and secondary nitrate. Because the nitrate was unstable under high temperature, the contribution of secondary nitrate to PM2.5 during the epidemic control period of 2021 (summer, 21.2%) was much lower than that during the epidemic control period of 2020 (winter, 60.6%); however, the formation of secondary components always dominated the contribution of PM2.5 sources. Therefore, emissions of NOx and SO2 should be further controlled to continuously reduce ambient PM2.5 concentrations in Chinese cities.

[Multi-omics analysis of regulating effects of hyperoside on lipid metabolism in high-fat diet mice].

The aim of this study was to explore the regulating effects of hyperoside (Hyp) on lipid metabolism in high-fat diet mice. The high-fat diet mouse model was established by high-fat diet induction. After 5 weeks of Hyp intragastric administration in high-fat diet mice, the serum lipid levels before and after Hyp administration were measured by the corresponding kits. The tissue structure of mouse liver was observed by HE staining before and after Hyp administration. The changes of intestinal flora and transcriptome were measured by Illumina platforms. Liquid chromatography-mass spectrometry (LC-MS) was used to determine non-targeted metabolites. The results showed that Hyp significantly reduced lipid levels in the high-fat diet mice and effectively restored the external morphology and internal structure of liver tissue. Hyp changed the species composition of the intestinal flora in high-fat diet mice, increased the abundance of beneficial flora such as Ruminococcus, and decreased the abundance of harmful flora such as Sutterella. Combined multi-omics analysis revealed that the effect of retinoic acid on lipid metabolism was significant in the high-fat diet mice treated with Hyp, while the increase of retinoic acid content was significantly negatively correlated with the expression of genes such as cyp1a2 and ugt1a6b, positively correlated with AF12 abundance, and significantly negatively correlated with unidentified_Desulfovibrionaceae abundance. These results suggest that Hyp may modulate the abundance of AF12, unidentified_Desulfovibrionaceae and inhibit the expression of genes such as cyp1a2 and ugt1a6b, thus increasing the content of retinoic acid and regulating lipid metabolism in the high-fat diet mice.

[Continuous PM2.5 Composition Measurements for Source Apportionment During Air Pollution Events].

To explore the application of high-temporal-resolution data in PM2.5 source apportionment during air pollution events, ambient air PM2.5 components were continuously monitored in urban Nanjing from January to December, 2017. Commercially available instruments for continuous measurements were deployed to obtain hourly concentrations of elements, water-soluble ions, and carbonaceous components of PM2.5. Data for 15 elements and 5 bulk components during three pollution events(firework combustion during the Spring Festival, a spring sandstorm, and a winter haze event) and across the whole year comprised four datasets for source apportionment using positive matrix factorization(PMF), and the distribution of factor/source contributions and estimations of average concentrations of characteristic components were compared based on different input datasets(PMFfirework-sand-haze and PMFfull-year). The results showed that the identified factors/sources, factor profiles, and contributions differed largely between PMFfirework-sand-haze and PMFfull-year solutions. For example, the relative average contribution of the firework combustion factor derived from the PMFfull-year solution(was 1.50%) was far less than that of the PMFfirework solution. The dust factor had an average contribution of 8.51% in the PMFsand solution, which was approximately double that of the PMFfull-year solution. This might be explained by the fact that PMF assumes unvaried source compositions during the measurement campaign, meaning that the source apportionment results based on long-term observations will include bias due to changes in emission sources. Furthermore, during the firework combustion event, the estimated average concentration of K from the PMFfirework solution[(1.32±1.17) µg·m-3, P=0.64]was closer to measured value[(1.36±1.19) µg·m-3]than that of the PMFfull-year solution[(1.16±1.19) µg·m-3, P=0.0090]. For the sand storm event, the concentrations of Fe, Si, and Ti were significantly underestimated by the PMFfull-year solution[(0.061±0.042)-(1.06±0.65) µg·m-3, P<0.05], while their peak concentrations agreed well between the PMFsand estimations and the observations. During the winter haze event, all PM2.5 bulk components were well estimated by both the PMFfull-year and PMFhaze solutions. Based on these results, PMF source apportionment results based on continuous measurement data during pollution events can reasonably reflect short-term variations in characteristic PM2.5 components and their sources, which can improve the timeliness of air pollution source apportionment.

[Light-absorbing Properties and Sources of PM2.5 Organic Components at a Suburban Site in Northern Nanjing].

The light absorption of organic components in PM2.5 was investigated at a suburban site in northern Nanjing from September 2018 to September 2019, and PM2.5 compositional data and principal component analysis (PCA) were used to identify the sources of light-absorbing organic carbon (brown carbon, BrC). The results showed that the average light absorption coefficients of water-soluble organic carbon (WSOC) and methanol extractable organic carbon (MEOC) were (3.22±2.18) Mm-1 (Abs365,w) and (7.69±4.93) Mm-1(Abs365,m), respectively. Significant correlations were observed between Abs365,w and mass concentrations of WSOC (r=0.72, P<0.01) and between Abs365,m and mass concentrations of MEOC (r=0.62, P=0.04). Both Abs365,w and Abs365,m exhibited seasonal variations, with higher values during winter than during summer,and higher diel variations at night than during the day. This can be attributed to meteorological characteristics during the winter and nighttime, i.e., decreased boundary layer height and increased atmospheric stability, enhanced primary emissions in winter,and stronger photobleaching effects during the summer and during the day. The annual average Abs365,m/Abs365,w ratio (2.60±0.92) was much larger than the average mass ratio of MEOC/WSOC (1.37±0.30), indicating that the water-insoluble fraction of MEOC had a stronger light absorption effect and dominated BrC absorption. No strong correlation (r<0.60) was observed between WSOC, MEOC, Abs365,m, and mass concentrations of K+, indication that biomass burning was not the main source of BrC in the study location. The mass absorption efficiency of WSOC (MAE365,w) and MEOC (MAE365,m) and their ratios (MAE365,m/MAE365,w) showed similar seasonal variations to Abs365. The average MAE365 value of the water-insoluble fraction of MEOC (4.10±5.15) m2·g-1 was 6.0 and 2.9 times higher than that of MAE365,w and MAE365,m, respectively, suggested that BrC absorption was primarily attributable to water-insoluble components. In comparison to the absorption Ångström exponent of WSOC (ÅWSOC), ÅMEOC displayed marked temporal variability, which might be related to the seasonal variation in the emission of water-insoluble chromophores. According to the PCA results, the light absorption of PM2.5 organic was mainly attributed to secondary formation and anthropogenic primary emissions rather than biomass burning.

[Molecular mechanisms of anti-inflammatory action of AMPK].

AMP-activated protein kinase (AMPK), an evolutionarily conserved serine/threonine protein kinase, is known as the "cellular energy regulator" and a key molecule to maintain the energy balance of cells and organism. Recent studies have shown that AMPK exerts anti-inflammatory effects mainly through activating SIRT1, PGC-1α, p53, FoxO3a and p300, and down-regulating the activity of various inflammatory related proteins such as NF-κB and AP-1. This article reviews the molecular mechanisms of the anti- inflammatory effects of AMPK, and provides some clues for the development of AMPK-targeted therapeutics to treat inflammation and related diseases.

Inhibitory effect of luteolin on the proliferation of human breast cancer cell lines induced by epidermal growth factor.

The aim of the present study was to investigate the mechanism of the inhibitory effect of luteolin on the proliferation of breast cancer cells induced by epidermal growth factor (EGF) in vitro. MTT assay was used to detect the inhibitory effect of luteolin on the proliferation of MCF-7 and MDA-MB-231 cells as well as the effect on the proliferation of MCF-7 cells induced by EGF. Western blotting was used to detect the effects of luteolin on the expression of epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (Erk) 1/2 and signal transducers and activators of transcription-3 (STAT3) in MCF-7 cells induced by EGF. The results showed that luteolin could significantly inhibit the proliferation of MCF-7 and MDA-MB-231 cells, and the inhibitory effect on MCF-7 cells was more prominent. Moreover, luteolin could inhibit the proliferation of MCF-7 cells induced by EGF. Western blotting results showed that luteolin and AG1478 (an inhibitor of EGFR signaling) could inhibit the expression of p-EGFR and p-STAT3 in MCF-7 cells induced by EGF. Luteolin, LY294002 (an inhibitor of Akt signaling) and PD98059 (an inhibitor of Erk1/2 signaling) could inhibit the expression of p-Akt and p-Erk1/2 respectively in MCF-7 cells induced by EGF. Our data suggest that luteolin may inhibit EGF-induced activities of EGFR signaling pathway in human breast cancer cell lines, and PI3K/Akt, MAPK/Erk1/2, STAT3 signal pathways may be the major pathways that mediate the inhibitory effect of luteolin on EGFR signaling. Overall, our results may provide a theoretical foundation for the development of luteolin as anti-tumor drug.

Emodin inhibits breast cancer cell proliferation through the ERα-MAPK/Akt-cyclin D1/Bcl-2 signaling pathway.

BACKGROUND: The aim of the present study was to investigate the involvement of emodin on the growth of human breast cancer MCF-7 and MDA-MB-231 cells and the estrogen (E2) signal pathway in vitro. MATERIALS AND METHODS: MTT assays were used to detect the effects of emodin on E2 induced proliferation of MCF-7 and MDA-MB-231 cells. Flow cytometry (FCM) was applied to determine the effect of emodin on E2-induced apoptosis of MCF-7 cells. Western blotting allowed detection of the effects of emodin on the expression of estrogen receptor α, cyclin D1 and B-cell lymphoma-2 (Bcl-2), mitogen-activated protein kinases (MAPK) and phosphatidylinostiol 3-kinases (PI3K). Luciferase assays were emplyed to assess transcriptional activity of ERα. RESULTS: Emodin could inhibit E2-induced MCF-7 cell proliferation and anti-apoptosis effects, and arrest the cell cycle in G0/G1 phase, further blocking the effect of E2 on expression and transcriptional activity of ERα. Moreover, Emodin influenced the ER α genomic pathway via downregulation of cyclin D1 and Bcl-2 protein expression, and influenced the non-genomic pathway via decreased PI3K/Akt protein expression. CONCLUSIONS: These findings indicate that emodin exerts inhibitory effects on MCF-7 cell proliferation via inhibiting both non-genomic and genomic pathways.

[Prevalence and influence of diabetic retinopathy in populations at the age of ≥ 40 years in Luzhou City, Sichuan Province in 2011].

OBJECTIVE: To estimate the prevalence rate and risk factors of diabetic retinopathy(DR) in residents at the age of ≥ 40 years in Luzhou, Sichuan Province. METHODS: A multistage, stratified cluster random sampling method was used to select 7 communities of 8002 permanent residents ( ≥ 40 years old) for diabetes screened from May to December 2011 in Luzhou, Sichuan Province.Reference to the diagnostic criteria for diabetes recommended by World Health Organization in 1999, to the 1374 diabetes screening out patients with questionnaire, physical examination, fasting plasma glucose, 2-hours postprandial plasma glucose, glycosylated hemoglobin(HbAlc) and visual acuity, ocular diseases, fundus examination, etc.Some patients with fundus fluorescein angiography to the DR diagnosis, diagnostic criteria with reference to the diagnosis standard made by Chinese Ocular Fundus Diseases Society, Chinese Ophthalmological Society, Chinese Medical Association in 1984. Rates between the groups were compared using χ(2) test, trend χ(2) test or Fisher exact test, using multivariate analysis of risk factors associated with DR screening. RESULTS: A total of 8002 people were chosen and invited to take part in the project, 7478 persons completed the study, the overall response rate was 93.48%.One thousand three hundreds and seventy-four persons were diagnosed as diabetic patients, which took the proportion of 18.37% of the selected population, while 214 DR patients were found with the DR prevalence of 15.57%, occupying 2.86% of the total.Of 214 patients, 194 cases were non-proliferative diabetic retinopathy, making up 90.65% of DR patients, while 7 cases were found to be proliferative diabetic retinopathy, constitute 9.35% of DR patients. Multi-factor analysis manifest that there were close relationship between diabetic duration (trend χ(2) = 189.21, P < 0.01) , the level of HbAlc (χ(2) = 30.021, P < 0.01) , coronary heart disease (χ(2) = 4.075, P = 0.044) and DR prevalence. CONCLUSIONS: The prevalence of DR is high in the diabetic residents in Luzhou, Sichuan Province. Diabetic duration, the level of HbAlc and coronary heart disease are the significant factors to influence DR development. These results indicate that the changes of the level of HbAlc are closely related to the genesis and development of DR among the diabetic patients.

[Inhibitory effect of luteolin on the angiogenesis of chick chorioallantoic membrane and invasion of breast cancer cells via downregulation of AEG-1 and MMP-2].

The purpose of the present study was to investigate the effect of luteolin on the angiogenesis and invasion of breast cancer cells. MTT assay was used to examine breast cancer proliferation. The chick chorioallantoic membrane model was used to assess the angiogenesis effect. Wound healing assay was used to assess cell invasion ability. Western blot was used to analyze Bcl-2, AEG-1 and MMP-2 expression levels. The results showed luteolin inhibited MCF-7 cells proliferation in a dose- and time-dependent manner, and the expression of Bcl-2 protein was decreased. Luteolin had a strong anti-angiogenesis of chick chorioallantoic membrane. After treatment of MCF-7 cells with luteolin at 60 µmol/L for 48 h, migration rate was reduced by 71.07% compared with control (P < 0.01). After treatment of MCF-7 cells with luteolin at 60 µmol/L for 48 h, the expression of AEG-1 and MMP-2 was reduced by 82.34% (P < 0.05) and 85.70% (P < 0.05) respectively, compared with control. In conclusion, the results suggest that luteolin can inhibit the proliferation of breast cancer cells, and suppress the expression of Bcl-2. Furthermore, luteolin has strong anti-angiogenesis of chick chorioallantoic membrane and anti-invasive activity on breast cancer cells, and down-regulates the expression of AEG-1 and MMP-2.

[Relationship between the inhibitory effect of fraxetin on breast cancer and estrogen signaling pathway].

Estrogen signaling pathways play an important role in the regulation of the physiological function of breast cancer cell proliferation and apoptosis. The article used MTT assay, flow cytometer analysis and Western blot to detect the inhibition of fraxetin on MCF-7 cell cycle distribution and apoptosis, ERα, cyclin D1 and Bcl-2 expression levels, MAPK and PI3K signaling pathway to investigate the mechanism of anti-breast cancer of fraxetin. The results showed fraxetin inhibited E2ß-stimulated MCF-7 cell proliferation in a dose- and time-dependent manner, reversed E2ß-induced anti-apoptosis and promoted G0/G1 phase arrest. After treatment with fraxetin, the expression of ERα in MCF-7 cell was decreased, and estrogen genomic signaling pathway was inhibited by down-regulating the expression of cyclin D1 and Bcl-2 proteins. After MCF-7 cells were treated with fraxetin, the expressions of MAPK/Erk1/2 protein were reduced, which affected estrogen non-genomic signaling pathway. The results suggest fraxetin plays a part in anti-breast cancer function through E2ß-mediated genomic and non-genomic signaling pathways.

Luteolin inhibits proliferation induced by IGF-1 pathway dependent ERα in human breast cancer MCF-7 cells.

The growth of many breast tumors is stimulated by IGF-1, which activates signal transduction pathways inducing cell proliferation. ERα is important in this process. The aim of the study was to investigate relationships in vitro among inhibitory effects of luteolin on the growth of MCF-7 cells, IGF-1 pathway and ERα. Our results showed that luteolin could effectively block IGF-1-stimulated MCF-7 cell proliferation in a dose- and time- dependent manner and block cell cycle progression and induce apoptosis evidenced by the flow cytometric detection of sub-G1DNA content. Luteolin markedly decreased IGF-1-dependent IGF-1R and Akt phosphorylation without affecting Erk1/2 phosphorylation. Further experiments pointed out that ERα was directly involved in IGF-1 induced cell growth inhibitory effects of luteolin, which significantly decreased ERα expression. Knockdown of ERα in MCF-7 cells by an ERα-specific siRNA decreased the IGF-1 induced cell growth inhibitory effects of luteolin. ERα is thus a possible target of luteolin. These findings indicate that the inhibitory effect of luteolin on the growth of MCF-7 cells is via inhibiting IGF-1 mediated PI3K-Akt pathway dependent on ERα expression.

[Wogonin inhibits IGF-1-stimulated cell growth and estrogen receptor α expression in breast adenocarcinoma cell and angiogenesis of chick chorioallantoic membrane].

The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model.

[Antibacterial activity and mechanism of baicalein].

Baicalein (BAI) is an effective bactericide. The antibacterial activity and mechanism experiments were carried out by determining conductivity and content of macromolecules of membrane penetrability, the oxidative respiratory metabolism and protein synthesis changes and the inhibition of DNA topoisomerase activities. Electrical conductivity and the number of large molecules of BAI increased 2.48% and 1.8%, respectively, than that of the control. However, the membrane integrity did not destroyed by BAI directly. With BAI treatment, inhibition rates of activities for SDH and MDH were 56.2% and 57.4%, respectively, demonstrating that BAI could inhibit cell respiratory. After treated with BAI for 20 h, the total soluble content of proteins decreased by 42.83%. Moreover, the activities of DNA topoisomerase I and II were inhibited completely by 0.2 mmol x L(-1) BAI. These results indicated that BAI had obvious antibacterial activity on Staphylococcus aureus. The mechanism is that it could affect bacterial membrane penetrability, inhibit protein synthesis and influence SDH, MDH and DNA topoisomerase I and II activities to exert its antibacterial functions.

[Purification and properties of isoflavone-glucosidase].

A high activity isoflavone-glucosidase, which hydrolysis glycosides, was obtainde using liquid fermentation from Absidia sp. R strain. The isoflavone-glucosidase was purified 11 folds with yielding rate of 10.9% after ammonium sulfate precipitation and DEAE-Cellocuse (DE-52) ion exchange chromatography. SDS-PAGE results showed that the molecular weight is 53kD. And the optimum temperature, the optimum pH, Km and pI of the enzyme are 50 deegrees C, 5.0, 1.3 x 10(-2) mol/L and 3.2, respectively. The isoflavone-glucosidase is also rather stable under 60 degrees C and in pH range from 5.0 to 7.0. The enzyme can be activated by Co2+ and Ca2+, and be inhibited by Ag+ and Cu2+.