Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 56
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Sci Total Environ ; 734: 138651, 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32460085

RESUMO

High particulate matter (PM) pollution frequently occurs in winter over northern China , resulting in threats to human health. To date, there are limited studies to link source apportionments and health risk assessments in the different size-resolved PM samples during high PM events. In this study, size-segregated PM samples were collected in Linfen, a typical coal-burning city, in northern China during a wintertime haze pollution. In addition to water-soluble ions and carbon contents, metallic elements in the different size-segregated PM samples were also determined for health risk assessments by inhalation of PM. During the sampling period, the average concentration of PM10 was 274 ±â€¯57 µg m-3 with a major fraction (73%) of organic material and secondary-related aerosols, and an insignificant portion of trace elements (TEs, ~ 3%). The size distribution showed that As and Se, markers of coal combustion, exhibited a mono-modal distribution with a major peak at 0.4-0.7 µm and the others mostly possessed mono-/bi-modal patterns with a major peak at 3.3-5.8 µm. The cancer risk (CR) resulted from PM10 metals by inhalation was estimated to be 2.91 × 10-5 for children and 7.75 × 10-5 for adults while non-cancer risk (NCR) was 2.10 for children and 0.70 for adults. Chromium (Cr) was the dominant species (~89%) of cancer risk in PM10. Road dust was a major fraction (~65%) to total metals in coarse PM (dp > 3.3 µm) whereas coal combustion was a dominant source (~55%) in submicron (dp < 1.1 µm) PM metals. However, traffic emissions (40%) and coal combustion (36%) were the dominant sources of CR since both emissions contributed major fractions (74%) to Cr, especially in submicron PM which exhibited high deposition efficiency of TEs into respiratory tracts, resulting in high CR in Linfen City.

2.
Sci Total Environ ; 728: 138013, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32361103

RESUMO

High-time-resolution (3-hour) PM2.5 samples were collected simultaneously from the rural and urban areas in the Yangtze River Delta region during winter. The aerosol samples were analyzed for carbonaceous components, organic tracers, water-soluble inorganic ions and stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions of total carbon and total nitrogen. The values of PM2.5 and secondary organic carbon (SOC) for both sampling sites were observed 2 times higher in haze events compare to those in clear days, implying severe pollution occurred by photochemical oxidation during haze periods. The PM mass of rural samples showed similar temporal trend and significant correlation with the urban PM, reflecting pollution sources or their formation process are most likely identical. Diurnal variations of PM2.5 and carbonaceous components revealed that pollution levels increased at daytime due to the photochemical oxidation. In addition, SOC and OC were influenced by the relative humidity (RH%) and temperature (T °C), indicating that such meteorological factors play important roles in the occurrence of regional air pollution. The concentrations of levoglucosan, polycyclic aromatic hydrocarbons, hopanes, and n-alkanes were 625 ± 456 and 519 ± 301 ng m-3, 32.6 ± 24.7 and 28.7 ± 20.1 ng m-3, 1.83 ± 1.51 and 1.26 ± 1.34 ng m-3, and 302 ± 206 and 169 ± 131 ng m-3 for rural and urban samples, respectively. Levoglucosan is the most abundant organic compounds, exhibited 2-3 times higher in haze than clear days, suggesting biomass burning (BB) emission substantially affects the haze pollution in winter. Furthermore, NO3- was the dominant ionic species followed by SO42-, NH4+, Cl- and other minor species for both sites. The δ13C and δ15N values demonstrate that anthropogenic activities such as fossil fuel combustion and BB are the major sources for carbonaceous and nitrogenous aerosols. This study implies that both the regional anthropogenic emissions and meteorological conditions influenced the regional haze formation, leading enhancement of pollution levels in eastern China during winter.

3.
Sci Total Environ ; 719: 137416, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32145492

RESUMO

Oxalate-iron is an integral part of the photochemical system in the atmosphere. Here, we combined high-resolution online observations and laboratory simulations to discuss the distribution of oxalate and oxalate-iron photochemical system in Nanjing atmosphere at the molecular level. The results show that the oxidation state of iron in the oxalate-iron photochemical system changes significantly and regularly. Among them, Fe (II)/Fe (III) is 3.82 during the day and 0.76 at night. At the same time, Cl- may accelerate the generation of hydroxyl radicals in the system and promote the photooxidation rate of oxalate. Oxalate can be converted into formate (C1) and acetate (C2) in the photochemical system, but <4% of degraded oxalate is converted, which means that the photochemical system may not be the main source of formate and acetate in the atmosphere. Besides, the ratio of C1/C2 < 1 in the conversion is opposite to the ratio of C1/C2 > 1 in the general secondary conversion, which means that not all ratio of C1/C2 in the photochemical pathway is >1. These results are beneficial for us to understand the effect of the oxalate-iron photochemical system on the distribution of oxalate in the atmosphere, and also help us to analyze the conversion of organics in the atmospheric aqueous phase.

4.
Environ Sci Technol ; 54(5): 2626-2634, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-31944676

RESUMO

Secondary sulfate aerosols played an important role in aerosol formation and aging processes, especially during haze episodes in China. Secondary sulfate was formed via atmospheric oxidation of SO2 by OH, O3, H2O2, and transition-metal-catalyzed (TMI) O2. However, the relative importance of these oxidants in haze episodes was strongly debated. Here, we use stable sulfur isotopes (δ34S) of sulfate aerosols and a Rayleigh distillation model to quantify the contributions of each oxidant during a haze episode in Nanjing, a megacity in China. The observed δ34S values of sulfate aerosols showed a negative correlation with sulfur oxidation ratios, which was attributed to the sulfur isotopic fractionations during the sulfate formation processes. Using the average fractionation factor calculated from our observations and zero-dimensional (0-D) atmospheric chemistry modeling estimations, we suggest that OH oxidation was trivial during the haze episode, while the TMI pathway contributed 49 ± 10% of the total sulfate production and O3/H2O2 oxidations accounted for the rest. Our results displayed good agreement with several atmospheric chemistry models that carry aqueous and heterogeneous TMI oxidation pathways, suggesting the role of the TMI pathway was significant during haze episodes.


Assuntos
Poluentes Atmosféricos , Aerossóis , Catálise , China , Monitoramento Ambiental , Peróxido de Hidrogênio , Metais , Material Particulado , Isótopos de Enxofre
5.
J Clin Lab Anal ; 34(2): e23065, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31617251

RESUMO

BACKGROUND: Inflammation is a necessary component of chronic kidney disease (CKD) that can be attributed to an accumulation of toxins and a reduced clearance of proinflammatory cytokines. Procalcitonin (PCT) is a widely applied biomarker in the diagnosis of infection, and considering the presence of pre-existing inflammation in CKD patients, the PCT level could be high in such a population; however, no reference value for PCT in CKD patients has been available to date. METHODS: During the present study period, 361 CKD patients and 119 healthy controls were included. The PCT level and other biochemistry parameters were assayed by using a COBAS system. Statistical analysis was conducted to compare the differences in PCT levels and other biochemistry parameters between the two groups, and linear regression was used to assess the correlation between two variables. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of PCT and the optimal cutoff value to differentiate between CKD patients and healthy controls. RESULTS: The PCT level in CKD patients was significantly higher than that in healthy controls, and among the CKD patients, the PCT level was increased with advanced clinical stage. Moreover, PCT was moderately correlated with CysC. The optimal off-value was 0.075 with a sensitivity of 94.7% and specificity of 90.8%. CONCLUSION: The PCT level was significantly higher in CKD patients than in healthy controls, and the reference value for CKD patients should be adjusted to avoid unnecessary antibiotic treatments which may pose a negative impact on residual renal function.

6.
Huan Jing Ke Xue ; 40(8): 3438-3446, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854748

RESUMO

Organic aerosols have attracted increasing attention recently due to their significant contribution to fine particles (PM2.5) and their complex components and sources. In this study, a total of 40 PM2.5 samples were collected simultaneously with high-volume samplers in Changchun from 16th Oct to 29th Nov 2016. Organic carbon (OC), elemental carbon (EC), non-polar organic compounds including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and hopanes, and levoglucosan in atmospheric fine particles were analyzed. The main sources of organic aerosols were identified by molecular markers, diagnostic ratios, and a principal component analysis-multiple liner regression (PCA-MLR) model. The results showed that the average mass concentration of PM2.5 was (79.0±55.7) µg·m-3, and the averaged OC and EC mass concentrations were (20.7±15.6) µg·m-3 and (2.2±1.1) µg·m-3, which accounted for 26.2% and 2.8% of PM2.5, respectively. The total average concentration of the tested non-polar organic compounds was (186.3±104.5) ng·m-3 and, in descending order, this was composed of n-alkane (101.3±67.0) ng·m-3, polycyclic aromatic hydrocarbons (81.4±46.0) ng·m-3, hopanes (3.8±1.9) ng·m-3. The PCA-MLR model results showed that the relative contributions of the main sources of organic aerosols were coal combustion (47.0%), biomass burning (42.6%), and traffic emission (10.4%).

7.
Huan Jing Ke Xue ; 40(10): 4355-4363, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854802

RESUMO

In this study, hourly mass concentrations of atmospheric gases (mainly NH3) and secondary inorganic aerosols (mainly NH4+, NO3-, and SO42-) in Nanjing City were continuously measured during the fall of 2018 by an online gas and aerosol chemical component monitor. The dataset was used to investigate the variation characteristics of ambient NH3 and NH4+ during polluted and non-polluted periods, and to explore the potential chemical mechanism during gas-to-particle conversion between NH3 and NH4+. The results show that throughout the sampling period, the mean values (±1σ) of the mass concentrations of NH3 and NH4+ were (15.3±6.7) µg·m-3 and (11.3±7.8) µg·m-3, respectively, and that their diurnal profiles were distinct between pollution and non-pollution periods. Analysis of the potential contribution sources indicated that local contributions exceeded long-range transport as the dominant source of measured NH3 and NH4+, suggesting that urban areas can be hotspots of NH3 emissions. Further in-depth analysis revealed that the process of gas-to-particle conversion was the main driving force with respect to controlling diurnal variations in NH3 and NH4+. Specifically, pollution episodes were characterized by low temperature (7.5-12.5℃) and high humidity (50%-90%) meteorological conditions. These conditions tended to accelerate the reaction rate of gas-to-particle conversion and facilitate the formation of aerosol ammonium, leading to pronounced (NH4)2SO4 and NH4NO3 increases during pollution events. These findings clarify the sources of NH3 in the urban atmosphere and its potential contribution to the formation of particulate matter.

8.
Environ Sci Technol ; 53(21): 12247-12256, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31558018

RESUMO

Nitrogenous aerosols are ubiquitous in the environment and thus play a vital role in the nutrient balance as well as the Earth's climate system. However, their abundance, sources, and deposition are poorly understood, particularly in the fragile and ecosensitive Himalayan and Tibetan Plateau (HTP) region. Here, we report concentrations of nitrogen species and isotopic composition (δ15N) in aerosol samples collected from a forest site in the HTP (i.e., Southeast Tibet). Our results revealed that both organic and inorganic nitrogen contribute almost equally with high abundance of ammonium nitrogen (NH4+-N) and water-insoluble organic nitrogen (WION), contributing ∼40% each to aerosol total nitrogen (TN). The concentrations and δ15N exhibit a significant seasonality with ∼2 times higher in winter than in summer with no significant diurnal variations for any species. Moreover, winter aerosols mainly originated from biomass burning emissions from North India and East Pakistan and reached the HTP through a long-range atmospheric transport. The TN dry deposition and total deposition fluxes were 2.04 kg ha-1 yr-1 and 6.12 kg ha-1 yr-1 respectively. Our results demonstrate that the air contamination from South Asia reach the HTP and is most likely impacting the high altitude ecosystems in an accepted scenario of increasing emissions over South Asia.


Assuntos
Poluentes Atmosféricos , Nitrogênio , Aerossóis , Ecossistema , Monitoramento Ambiental , Florestas , Índia , Paquistão , Estações do Ano , Tibet
9.
Zhongguo Zhen Jiu ; 39(7): 792-8, 2019 Jul 12.
Artigo em Chinês | MEDLINE | ID: mdl-31286745

RESUMO

OBJECTIVE: To review systematically the safety and effectiveness of acupuncture-related therapies on ovulation rate and pregnancy rate in patients with polycystic ovary syndrome (PCOS). METHODS: From PubMed, EMbase, the Cochrane Library, China Biology Medicine disc (CBM), China National Knowledge Infrastructure (CNKI), Wanfang database and VIP database, the randomized controlled trials (RCTs) on PCOS were retrieved in the period from the date of database establishment to January 8, 2018. Two researchers screened the articles, extracted the data and assessed the bias risk of the eligible trials independently. Using Stata 13.0 and WinBUGS 1.4.3 software, the data were analyzed. RESULTS: A total of 39 RCTs were collected, including 4605 cases of PCOS and 14 kinds of acupuncture-related therapies and the comprehensive therapies. The short-term therapeutic effects were observed. The results of mesh meta-analysis showed: regarding the ovulation rate, the effects of the acupuncture-medication therapy were better than western medication. The top 6 therapeutic measures were the treatment with acupoint thread-embedding therapy and medication (93.3%), the treatment with moxibustion and Chinese herbal medicine (91.4%), moxibustion (74.5%), the treatment with acupuncture and medication (65.7%), the treatment with acupuncture-moxibustion and auricular point therapy (61.9%) and the treatment with acupuncture and auricular point therapy (49.6%). Regarding the pregnancy rate, the effects of the acupuncture-medication therapy were better than western medication. The top 6 therapeutic measures were the treatment with acupuncture and auricular point therapy (91.5%), the treatment with moxibustion and Chinese herbal medication (86.9%), the treatment with acupuncture-moxibustion and auricular point therapy (81.1%), the treatment with acupoint thread-embedding therapy and medication (69.4%), the treatment with acupuncture and medication (66.1%) and the treatment with placebo and western medication (58.7%). CONCLUSION: Among acupuncture-related therapies, the combined treatment is more advantageous than single therapy and its safety is superior to western medication. The combined therapies are various in advantages. Because of the limitation of the present researches, it needs a large scale of RCTs with rational design, high quality and proper methods to verify this research conclusion.


Assuntos
Terapia por Acupuntura , Síndrome do Ovário Policístico , China , Feminino , Humanos , Metanálise em Rede , Ovulação , Síndrome do Ovário Policístico/terapia , Gravidez , Taxa de Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto
10.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1847-1853, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257755

RESUMO

Ammonium salts, including ammonium nitrate, ammonium sulfate and ammonium hydrogen sulfate, are the main components of secondary inorganic aerosols and play an important role in the formation of haze events. The sources and transformation processes of atmospheric ammonium have received more and more attention. In this study, we modified the previous stable isotope analysis technique by improving the injection volume and adding a pH adjustment step, which gave a rapid and accurate measurement of ammonium nitrogen isotope ratio in atmospheric aerosol samples. Firstly, we added alkaline hypobromite to the extracted solution of the atmospheric aerosol filter samples (0.25 µg·mL-1 ammonium nitrogen in 4 mL) to oxidize ammonium (NH4+) to nitrite (NO2-). Then, after adjusting the pH, nitrite (NO2-) was reduced to nitrous oxide (N2O) by hydroxylamine hydrochloride under pH <0.3. Finally, nitrous oxide (N2O) was analyzed by Precon-GasBench-IRMS system to measure ammonium nitrogen isotope ratio. Our approach required low amount of NH4+ and avoided the use of highly toxic and explosive reagents. Meanwhile, the precision of our method could reach as high as 0.2‰ (n=10). This method could increase the NH4+ reduction efficiency to 100% at a condition of pH <0.3 and satisfy the demands of precision and accuracy for determination of ammonium nitrogen isotope in atmospheric aerosol samples. This method would help us better understand the sources, evolutions, chemical and deposition processes of atmospheric ammonium.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Amônio/análise , Monitoramento Ambiental , Hidroxilamina/química , Isótopos de Nitrogênio/análise , Nitrogênio , Oxirredução , Sais
11.
Huan Jing Ke Xue ; 39(10): 4439-4445, 2018 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-30229589

RESUMO

PM2.5 is an important atmospheric pollution component and has a complicated composition. The chemical constitution of PM2.5 in Nanjing northern region during March 2016 was analyzed using the Dinoex ICS-3000 and ICS-2000 ion chromatograph and DRI Model 2001A thermal/optical carbon analyzer, and the carbon isotopic compositions were analyzed using EA-IRMS from Thermo Scientific in order to explore pollution behaviors and source apportionment of PM2.5. The results showed that the mean concentration of atmospheric PM2.5 was (106.16±48.70) µg·m-3, which equated with heavy pollution. Meanwhile, 88% of the samples exhibited the presence of the secondary organic pollutants. The average concentration of secondary organic carbon (SOC) was (3.58±2.78) µg·m-3 and this high concentration was attributed to the reaction of O3 with atmospheric hydrocarbons under ultraviolet light on sunny days. In addition, δ13CTC in PM2.5 ranged from -26.56‰ to -23.75‰ and the mean was (-25.47‰±0.63‰). Combining the various analyses, we concluded that atmospheric PM2.5 for the study area was mainly derived from coal combustion, vehicle exhaust, geology (natural sources) and biomass burning.

12.
Huan Jing Ke Xue ; 39(7): 3033-3041, 2018 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-29962123

RESUMO

In this study, PM2.5 samples were collected from October to November of 2015 in the northern suburb of Nanjing. The mass concentrations of organic carbon (OC), elemental carbon (EC), and levoglucosan in the samples were analyzed by thermal optical transmittance (TOT) and ion chromatography. The average concentrations of OC and EC were respectively (11.3±4.9) µg·m-3 and (1.1±0.9) µg·m-3. The average total carbon (TC) was 22.9%, and the OC/EC was 7.4. The quality concentrations of PM2.5, OC, EC, and SOC all reflected daytime features, and the correlation between OC and EC was better during the day than at night (correlation coefficients of 0.86 for day and 0.7 for night). By analyzing the mass concentrations of PM2.5, levoglucosan, and SOC, as well as the data of backward trajectories and fire point data, it was determined that the northern suburb of Nanjing is affected by the long-distance transportation of biomass from Hebei and other places from October 13-16. The correlations between levoglucosan and OC, EC, or SOC were significant (correlation coefficients of 0.78, 0.79, and 0.65, respectively), and the contribution of biomass combustion during sampling to OC was 21.9%.

13.
J Cancer Res Ther ; 14(Supplement): S138-S144, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29578164

RESUMO

Background: This study aims to investigate the correlations of positive rate of phosphatase and tensin homolog (PTEN) protein with lymph node metastasis (LNM) and tumor node metastasis (TNM) staging of nonsmall cell lung cancer (NSCLC) patients by conducted a meta-analysis. Materials and Methods: Covering several electronic databases (Embase, Cochrane Library, China BioMedicine, China National Knowledge Infrastructure, PubMed, and Web of Science), published papers eligible for enrollment in the current meta-analysis had to fulfill our predefined selection criteria. Odds ratios (ORs) with their 95% confidence interval (95%CI) were aggregated utilizing comprehensive meta-analysis 2.0 software (Biostatic Inc., Englewood, New Jersey, USA). Results: Twelve cohort studies with a total of 419 NSCLC patients were incorporated into the current meta-analysis. A decreased positive rate of PTEN protein was detected in NSCLC patients with TNM stage III-IV rather than those patients with TNM stage I-II (OR = 0.454, 95%CI = 0.338-0.610, P < 0.001). PTEN in NSCLC patients without LNM expressed higher than that in the patients with LNM (OR = 0.532, 95%CI: 0.299-0.948, P = 0.032). Ethnicity-stratified analysis demonstrated a negative relationship between positive rate of PTEN protein and TNM staging of NSCLC among both Asians and Caucasians (both P < 0.05). However, we found no significant association between positive rate of PTEN protein and LNM among Asians and Caucasians (both P > 0.05). Conclusion: Our findings indicate that decreased positive rate of PTEN protein may be linked to TNM staging and LNM in NSCLC, and it could be an important diagnostic biomarker of NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Linfonodos/patologia , PTEN Fosfo-Hidrolase/metabolismo , Biomarcadores Tumorais , Humanos , Metástase Linfática , Estadiamento de Neoplasias , Razão de Chances , PTEN Fosfo-Hidrolase/genética , Viés de Publicação
14.
Acta Pharmacol Sin ; 39(3): 336-344, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29072256

RESUMO

Rapamycin and its derivative possess anti-atherosclerosis activity, but its effects on adhesion molecule expression and macrophage adhesion to endothelial cells during atherosclerosis remain unclear. In this study we explored the effects of rapamycin on ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells in vitro and the underlying mechanisms. Ox-LDL (6-48 µg/mL) dose-dependently increased the protein levels of two adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and E-selectin, in human umbilical vein endothelial cells (HUVECs), whereas pretreatment with rapamycin (1-10 µmol/L) dose-dependently inhibited ox-LDL-induced increase in the adhesion molecule expression and macrophage adhesion to endothelial cells. Knockdown of mTOR or rictor, rather than raptor, mimicked the effects of rapamycin. Ox-LDL (100 µg/mL) time-dependently increased PKC phosphorylation in HUVECs, which was abolished by rapamycin or rictor siRNA. Pretreatment with PKC inhibitor staurosporine significantly reduced ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells, whereas pretreatment with PKC activator PMA/TPA attenuated the inhibitory effect of rapamycin on adhesion molecule expression. Ox-LDL (100 µg/mL) time-dependently increased c-Fos levels in HUVECs, and pretreatment with rapamycin or rictor siRNA significantly decreased expression of c-Fos. Knockdown of c-Fos antagonized ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells. Our results demonstrate that rapamycin reduces ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells by inhibiting mTORC2, but not mTORC1, and mTORC2 acts through the PKC/c-Fos signaling pathway.


Assuntos
Genes fos/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Inflamação/prevenção & controle , Lipoproteínas LDL/antagonistas & inibidores , Alvo Mecanístico do Complexo 2 de Rapamicina/antagonistas & inibidores , Proteína Quinase C/antagonistas & inibidores , Sirolimo/farmacologia , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Selectina E/metabolismo , Técnicas de Silenciamento de Genes , Células Endoteliais da Veia Umbilical Humana/enzimologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Lipoproteínas LDL/farmacologia , Alvo Mecanístico do Complexo 2 de Rapamicina/genética , RNA Interferente Pequeno/farmacologia , Proteína Companheira de mTOR Insensível à Rapamicina/antagonistas & inibidores , Proteína Companheira de mTOR Insensível à Rapamicina/genética , Proteína Regulatória Associada a mTOR/antagonistas & inibidores , Proteína Regulatória Associada a mTOR/genética , Transdução de Sinais/efeitos dos fármacos , Estaurosporina/farmacologia , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacologia
15.
Environ Pollut ; 231(Pt 1): 654-662, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28846986

RESUMO

Fine particulate matter (PM2.5) samples were collected using a high-volume air sampler and pre-combusted quartz filters during May 2013 to January 2014 at a background rural site (47∘35 N, 133∘31 E) in Sanjiang Plain, Northeast China. A homologous series of dicarboxylic acids (C2-C11) and related compounds (oxoacids, α-dicarbonyls and fatty acids) were analyzed by using a gas chromatography (GC) and GC-MS method employing a dibutyl ester derivatization technique. Intensively open biomass-burning (BB) episodes during the harvest season in fall were characterized by high mass concentrations of PM2.5, dicarboxylic acids and levoglucosan. During the BB period, mass concentrations of dicarboxylic acids and related compounds were increased by up to >20 times with different factors for different organic compounds (i.e., succinic (C4) acid > oxalic (C2) acid > malonic (C3) acid). High concentrations were also found for their possible precursors such as glyoxylic acid (ωC2), 4-oxobutanoic acid, pyruvic acid, glyoxal, and methylglyoxal as well as fatty acids. Levoglucosan showed strong correlations with carbonaceous aerosols (OC, EC, WSOC) and dicarboxylic acids although such good correlations were not observed during non-biomass-burning seasons. Our results clearly demonstrate biomass burning emissions are very important contributors to dicarboxylic acids and related compounds. The selected ratios (e.g., C3/C4, maleic acid/fumaric acid, C2/ωC2, and C2/levoglucosan) were used as tracers for secondary formation of organic aerosols and their aging process. Our results indicate that organic aerosols from biomass burning in this study are fresh without substantial aging or secondary production. The present chemical characteristics of organic compounds in biomass-burning emissions are very important for better understanding the impacts of biomass burning on the atmosphere aerosols.


Assuntos
Poluentes Atmosféricos/análise , Ácidos Dicarboxílicos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Atmosfera/química , Biomassa , China , Compostos Orgânicos/análise , Estações do Ano
16.
Huan Jing Ke Xue ; 38(9): 3620-3627, 2017 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965240

RESUMO

Thirty indoor dust samples were collected from staff and study areas in a college in Foshan, and the As, Hg, Cd, Cu, Zn, Ni, Pb, and Cr contents were measured. The Spearman correlation coefficient, principal component analysis, and US EPA health risk assessment model were used to determine the sources and degree of pollution and the health risks. The results showed that the levels of the eight heavy metals were higher than the background values in Guangdong Province and the reported values in other Chinese cities, excluding Hg. The levels of the eight heavy metals were higher in the staff area than in the study area, but the difference was not significant. The eight heavy metals were derived from similar sources; Hg was mainly derived from outdoor anthropogenic sources, while the others were mainly derived from indoor anthropogenic sources. The daily non-carcinogenic exposure dose was in the following order:ingestion > dermal exposure > inhalation. Ingestion was the major pathway of heavy metal exposure from indoor dust. Except for Cr, the non-carcinogenic hazard indexes of ingestion and dermal exposure were taken from partial sample points > 1. All of the health risks were lower than the average risk thresholds of the heavy metals, and would not cause health risks to humans. Printers, copiers, instruments, and equipment were important sources of indoor pollution and risk sources of heavy metals. Thus, protective measures should be taken to reduce the risk of exposure.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Poeira/análise , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , China , Cidades , Humanos , Universidades
17.
Huan Jing Ke Xue ; 38(11): 4478-4485, 2017 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965390

RESUMO

A total of 32 daily PM2.5 samples were collected from December 2016 to February 2017 in the urban area of Xuzhou city. Water-soluble inorganic ions (WSⅡs), including F-, Cl-, NO3-, SO42-, Na+, Mg2+, NH4+, K+ and Ca2+, were determined by ion chromatography. The average mass concentration of PM2.5 was (164.8±77.3) µg·m-3 and the average total mass concentration of the nine ions was (67.5±36.1) µg·m-3, the contribution of the WSⅡs to the PM2.5 was more than 40.9%. The order of the concentrations of individual ions was NO3- > SO42- > NH4+ > Cl- > Ca2+ > K+ > Na+ > Mg2+ > F-. NH4+, NO3-, and SO42- (SNA) were the major components of the water-soluble ions in the PM2.5 measurement. The average mass concentration of WSⅡs in clean air, mild haze, and severe haze was (12.8±8.8), (59.0±22.8) and (86.3±36.0) µg·m-3, respectively. The contribution of SNA to WSⅡs was 86.4%, 82.8%, and 78.9%, respectively. The correlation between each component of SNA with each other was significant. NH4+, NO3-, and SO42- were in the form of (NH4)2SO4 and NH4NO3. Secondary formation, biomass burning, fossil fuel combustion, and dust were the major sources of the water-soluble ions in PM2.5.

18.
Biochem Biophys Res Commun ; 482(1): 93-99, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27815075

RESUMO

Foam cell formation, which is caused by imbalanced cholesterol influx and efflux by macrophages, plays a vital role in the occurrence and development of atherosclerosis. Humanin (HN), a mitochondria-derived peptide, can prevent the production of reactive oxygen species and death of human aortic endothelial cells exposed to oxidized low-density lipoprotein (ox-LDL) and has a protective effect on patients with in early atherosclerosis. However, the effects of HN on the regulation of cholesterol metabolism in RAW 264.7 macrophages are still unknown. This study was designed to investigate the role of [Gly14]-humanin (HNG) in lipid uptake and cholesterol efflux in RAW 264.7 macrophages. Flow cytometry and live cell imaging results showed that HNG reduced Dil-ox-LDL accumulation in the RAW 264.7 macrophages. A similar result was obtained for lipid accumulation by measuring cellular cholesterol content. Western blot analysis showed that ox-LDL treatment upregulated not only the protein expression of CD36 and LOX-1, which mediate ox-LDL endocytosis, but also ATP-binding cassette (ABC) transporter A1 and ABCG1, which mediate ox-LDL exflux. HNG pretreatment inhibited the upregulation of CD36 and LOX-1 levels, prompting the upregulation of ABCA1 and ABCG1 levels induced by ox-LDL. Therefore we concluded that HNG could inhibit ox-LDL-induced macrophage-derived foam cell formation, which occurs because of a decrease in lipid uptake and an increase in cholesterol efflux from macrophage cells.


Assuntos
Diferenciação Celular/fisiologia , Colesterol/metabolismo , Células Espumosas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Metabolismo dos Lipídeos/fisiologia , Lipoproteínas LDL/farmacocinética , Animais , Células Espumosas/citologia , Camundongos , Células RAW 264.7
19.
Environ Sci Technol ; 50(12): 6284-92, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27203471

RESUMO

Source quantification of carbonaceous aerosols in the Chinese outflow regions still remains uncertain despite their high mass concentrations. Here, we unambiguously quantified fossil and nonfossil contributions to elemental carbon (EC) and organic carbon (OC) of total suspended particles (TSP) from a regional receptor site in the outflow of Northeast China using radiocarbon measurement. OC and EC concentrations were lower in summer, representing mainly marine air, than in other seasons, when air masses mostly traveled over continental regions in Mongolia and northeast China. The annual-mean contribution from fossil-fuel combustion to EC was 76 ± 11% (0.1-1.3 µg m(-3)). The remaining 24 ± 11% (0.03-0.42 µg m(-3)) was attributed to biomass burning, with slightly higher contribution in the cold period (∼31%) compared to the warm period (∼21%) because of enhanced emissions from regional biomass combustion sources in China. OC was generally dominated by nonfossil sources, with an annual average of 66 ± 11% (0.5-2.8 µg m(-3)), approximately half of which was apportioned to primary biomass-burning sources (34 ± 6%). In winter, OC almost equally originated from primary OC (POC) emissions and secondary OC (SOC) formation from fossil fuel and biomass-burning sources. In contrast, summertime OC was dominated by primary biogenic emissions as well as secondary production from biogenic and biomass-burning sources, but fossil-derived SOC was the smallest contributor. Distinction of POC and SOC was performed using primary POC-to-EC emission ratios separated for fossil and nonfossil emissions.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis , Carbono , China , Monitoramento Ambiental , Fósseis , Estações do Ano
20.
PLoS One ; 11(1): e0146777, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26752047

RESUMO

BACKGROUND: Lectin-like oxidized low-density lipoprotein-1 (LOX-1) is the major receptor for oxidized low density lipoprotein (ox-LDL) uptake in human umbilical vein endothelial cells (HUVECs). Previously, we found that rapamycin inhibited ox-LDL accumulation in HUVECs, and this effect was related to its role in increasing the activity of autophagy-lysosome pathway. In this study, we determined whether rapamycin could also reduce ox-LDL uptake in HUVECs and investigated the underlying signaling mechanisms. RESULTS: Flow cytometry and live cell imaging showed that rapamycin reduced Dil-ox-LDL accumulation in HUVECs. Furthermore, rapamycin reduced the ox-LDL-induced increase in LOX-1 mRNA and protein levels. Western blotting showed that rapamycin inhibited mechanistic target of rapamycin (mTOR), p70s6k and IκBα phosphorylation triggered by ox-LDL. Flow cytometry implied that mTOR, NF-κB knockdown and NF-κB inhibitors significantly reduced Dil-ox-LDL uptake. Moreover, immunofluorescent staining showed that rapamycin reduced the accumulation of p65 in the nucleus after ox-LDL treatment for 30 h. mTOR knockdown decreased LOX-1 protein production and IκBα phosphorylation induced by ox-LDL. NF-κB knockdown and NF-κB inhibitors reduced LOX-1 protein production, but did not inhibit mTOR phosphorylation stimulated by ox-LDL. CONCLUSIONS: These findings demonstrate that rapamycin reduce mTOR phosphorylation and subsequently inhibit NF-κB activation and suppresses LOX-1, resulting in a reduction in ox-LDL uptake in HUVECs.


Assuntos
Imunossupressores/farmacologia , Lipoproteínas LDL/farmacocinética , Subunidade p50 de NF-kappa B/metabolismo , Receptores Depuradores Classe E/metabolismo , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Aterosclerose/metabolismo , Autofagia/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células , Progressão da Doença , Regulação Enzimológica da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Lisossomos/metabolismo , Fosforilação , Transdução de Sinais , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA