Evaluating the multi-variable influence on O3, NO2, and HCHO using BRTs and RF model.

This study addresses significant knowledge gaps in understanding the complex interplay between atmospheric chemistry and synoptic conditions. Using emerging machine learning techniques-Boosted Regression Trees (BRTs) and Random Forest (RF) models-we investigate the influence of synoptic conditions on pollutant levels. Several BRTs and RF models are developed to estimate surface concentrations of ozone (O3), nitrogen dioxide (NO2), and formaldehyde (HCHO). By considering a range of algorithmic structures and explanatory variables for each pollutant, the research aims to identify the most skillful predictive approaches and influential factors governing pollutant levels. The design seeks to highlight key determinants of concentration patterns without constraining the investigation to pre-defined model structures or explanatory variable sets. Introducing a novel methodology, Correlation Coefficient Differential Evaluation (C2DE), we quantitatively assess the influence of explanatory variables. C2DE reveals significant contributions from spatial variables (i.e., trajectory clusters at varying altitudes), formaldehyde to nitrogen dioxide ratio (FNR), and meteorological parameters. Specifically, spatial variables contribute approximately 28 % to O3 concentrations, while the FNR accounts for around 5.2-9.8 % of the overall influence. For NO2 and HCHO, spatial variables contribute around 26.5 % and 32.1 %, respectively. Moreover, when considering the combined influence of meteorological parameters, these collectively explain about 45.34 %, 35.31 %, and 45.41 % of the variations in O3, NO2, and HCHO concentrations, respectively. Thus, C2DE provides valuable insights into the relative contributions of these factors, aiding in the comprehensive evaluation of air quality dynamics. This underscores the need for a multifaceted approach to comprehending and effectively addressing air pollution before devising its control strategies.

A CNN-SVR model for NO2 profile prediction based on MAX-DOAS observations: The influence of Chinese New Year overlapping the 2020 COVID-19 lockdown on vertical distributions of tropospheric NO2 in Nanjing, China.

In this study, a hybrid model, the convolutional neural network-support vector regression model, was adopted to achieve prediction of the NO2 profile in Nanjing from January 2019 to March 2021. Given the sudden decline in NO2 in February 2020, the contribution of the Coronavirus Disease-19 (COVID-19) lockdown, Chinese New Year (CNY), and meteorological conditions to the reduction of NO2 was evaluated. NO2 vertical column densities (VCDs) from January to March 2020 decreased by 59.05% and 32.81%, relative to the same period in 2019 and 2021, respectively. During the period of 2020 COVID-19, the average NO2 VCDs were 50.50% and 29.96% lower than those during the pre-lockdown and post-lockdown periods, respectively. The NO2 volume mixing ratios (VMRs) during the 2020 COVID-19 lockdown significantly decreased below 400 m. The NO2 VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period. This phenomenon could be attributed to the 2020 COVID-19 lockdown. The NO2 VMRs before and after the CNY were significantly lower in 2020 than in 2019 and 2021 in the same period, which further proves that the decrease in NO2 in February 2020 was attributed to the COVID-19 lockdown. Pollution source analysis of an NO2 pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was transported southwards under the action of the north wind, and the subsequent unfavorable meteorological conditions (local wind speed of < 2.0 m/sec) resulted in the accumulation of pollutants.

McPrA - A new gas profile inversion algorithm for MAX-DOAS and apply to 50 m vertical resolution.

Air pollutants represent an environmental and health risk, and the methods for their effective assessment are of the greatest importance. The MAX-DOAS method is a reliable retrieval algorithm, enabling a vertical gas profile analysis. However, the current MAX-DOAS retrieval algorithm heavily relies on the a priori profile, limiting its accuracy. To address this issue, we introduced a novel MAX-DOAS trace gas profile inversion algorithm called McPrA, which is less dependent on the a priori profile. It employs the Monte Carlo method to resolve the problem of optimal estimation of trace gases. The gas vertical column density is obtained from the air mass factor calculated by SCIATRAN. Afterward, the trace gas vertical distribution is retrieved by combining the weight function with the a priori profile. A normalization process is also included to improve the matching of the weight function and the a priori profile. The McPrA algorithm enables greater flexibility in grid modification to achieve a higher vertical resolution of up to 50 m, while sensitivity experiments contribute to determining the optimal configuration of retrieval parameters, with a degree of freedom of over 3.0. Comparative verification experiments indicate that the McPrA algorithm accurately retrieves gas profiles, with a correlation coefficient of over 0.89 for NO2 in the first layer compared to in situ data. Furthermore, comparisons with WRF-Chem and the simulation of synthetic data demonstrate the effectiveness of the McPrA algorithm in accurately retrieving gas profiles.

Observation on the aerosol and ozone precursors in suburban areas of Shenzhen and analysis of potential source based on MAX-DOAS.

Long-term stereoscopic observations of aerosol, NO2, and HCHO were carried out at the Yangmeikeng (YMK) site in Shenzhen. Aerosol optical depths and NO2 vertical column concentration (NO2 VCD) derived from MAX-DOAS were found to be consistent with other datasets. The total NO2 VCD values of the site remained low, varying from 2 × 1015 to 8 × 1015 mol/cm2, while the HCHO VCD was higher than NO2 VCD, varying from 7 × 1015 to 11 × 1015 mol/cm2. HCHO VCD was higher from September to early November than that was from mid-late November to December and during February 2021, in contrast, NO2 VCD did not change much during the same period. In January, NO2 VCD and HCHO VCD were both fluctuating drastically. High temperature and HCHO level in the YMK site is not only driving the ozone production up but also may be driving up the ozone concentration as well, and the O3 production regime in the YMK site tends to be NOx-limited. At various altitudes, backward trajectory clustering analysis and Potential Source Contribution Function (PSCF) were utilized to identify possible NO2 and HCHO source locations. The results suggested that the Huizhou-Shanwei border and the Daya Bay Sea area were the key potential source locations in the lower (200 m) and middle (500 m) atmosphere (WPSCF > 0.6). The WPSCF value was high at the 1000 m altitude which was closer to the YMK site than the near ground, indicating that the pollution transport capability in the upper atmosphere was limited.

Evaluation and measurement of tropospheric glyoxal retrieved from MAX-DOAS in Shenzhen, China.

Glyoxal is one of the representative oxygenated volatile organic compounds in the atmosphere. Its accurate measurement has high significance for the determination of VOC emission sources and the calculation of the global budget of secondary organic aerosol. We investigated the spatio-temporal variation characteristics of glyoxal through observations over a 23-day period. Sensitivity analysis of simulated and actual observed spectra revealed that the accuracy of glyoxal fitting is primarily controlled by the wavelength range selected. Within the range of 420-459 nm, the value calculated using the simulated spectra was 12.3 × 1014 molecules/cm2 lower than the actual value, and the results obtained using the actual spectra included a large number of negative values. Overall, the wavelength range has a far stronger influence than other parameters. The wavelength range of 420-459 nm (excluding 442-450 nm) is the most suitable because it ensures minimal influence from interference components in the same wavelength. Within this range, the calculated value of the simulated spectra is the closest to the actual value, with a deviation of only 0.89 × 1014 molecules/cm2. Therefore, the 420-459 nm range (excluding 442-450 nm) was selected for further observation experiments. The fourth polynomial order was used in DOAS fitting, and constant terms were used to correct the actual spectral offset. In the experiments, the glyoxal slant column density primarily ranged from -4 × 1015 molecules/cm2 to 8 × 1015 molecules/cm2, and the near-ground glyoxal concentration ranged from 0.02 to 0.71 ppb. Regarding the average daily variation cycle, high values of glyoxal were concentrated around noon, which was similar with UVB. This indicates that the formation of CHOCHO was related to the emission of biological VOCs. Glyoxal was concentrated below 500 m and the pollution height began to rise around 09:00 and reached the maximum value around 12:00, after which they declined.

Study of SO2 measurement based on a dual optical path Fabry-Perot correlation spectroscopy.

This paper investigates a method for measuring SO2 concentration using Fabry-Perot interferometer correlation spectroscopy. In this method, the experimental system is designed as a separated beam, with the beam entering the F-P cavity at two incidence angles simultaneously to match the peak and valley positions of the SO2 absorption cross-section. The system achieves a 2σ detection limit of 28.2 ppm·m(15 cm) at a sampling frequency of 10 Hz. An outfield comparison experiment with the differential optical absorption spectroscopy method shows good agreement for the simultaneous measurement of SO2 concentration from sulfur combustion, with a correlation coefficient of R2 = 0.93. This study introduces a non-dispersive, highly accurate, and fast gas detection technique.

Transforming growth factor-ß1 attenuates inflammation and lung injury with regulating immune function in ventilator-induced lung injury mice.

Ventilator-induced lung injury (VILI) is a lung injury induced or aggravated by mechanical ventilation. Transforming growth factor (TGF)-ß1 is a cytokine that mediates immune function, enabling inflammatory attenuation and tissue repair. Here, we hypothesized that it plays an important role in the attenuation of VILI and inflammation. Ventilation with high tidal volume was performed on C57BL/6 mice to establish a VILI model. After 4 h of ventilation, mice were sacrificed (end of ventilation [EOV]) or extubated for resuscitation at 4 h (post-ventilation 4 h [PV4h]), 8 h (PV8h) and 24 h post-ventilation (PV1d). Recombinant mouse TGF-ß1 (rTGF-ß1) and the neutralization antibody of TGF-ß1 (nTAb) were used in vivo to examine the effect of TGF-ß1 on immune function and inflammatory attenuation in VILI mice. Lung injury was exacerbated at the same trend as the interleukin (IL)-1ß level, peaking at PV1d, whereas IL-6 and tumor necrosis factor (TNF)-α levels gradually reduced. Most active phagosomes, swollen round mitochondria, and cavitating lamellar bodies were observed at PV4h. The CD4+ T cells were significantly increased from PV4h to PV1d, and the CD8a + T cells were higher in the PV4h and PV1d groups; furthermore, the mice in the PV8h group showed highest proportion of CD4+CD8a+ T cells and CD4+/CD8a+ ratio. CD19 + and CD5 + CD19 + B cells in VILI mice began to increase at PV1d. The pulmonary expression of latent and monomer TGF-ß1 increased at PV4h and PV8h. Treatment of rTGF-ß1 only induced high expression of latent and monomer TGF-ß1 at EOV to decrease pulmonary levels of IL-1ß, IL-6, and TNF-α; however, lung injury attenuated from EOV to PV1d. TGF-ß1 induced the delayed elevation of CD4+/CD8a+ T cells ratio and activation of pulmonary CD4+CD8a+ double-positive T cells under certain conditions. Elastic fibers and celluloses, although relatively less proteoglycan, were observed with the overexpression of TGF-ß1 at PV4h and PV8h. In conclusion, TGF-ß1 attenuates the inflammatory response and lung injury of VILI via immune function regulation.

The vertical distribution and potential sources of aerosols in the Yangtze River Delta region of China during open straw burning.

To explore the impact of open straw burning on air quality in the Yangtze River Delta (YRD) and surrounding areas, three key cities in the YRD, namely Hefei, Nanjing, and Shanghai, were selected to observe changes in aerosol characteristics. Based on Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations from May to June 2021, the spatial-temporal distribution and potential sources of aerosol were studied. During the observation period, aerosol optical depth (AOD) in Shanghai was 55.15 % and 29.50 % higher than that in Hefei and Nanjing, respectively. For Shanghai, aerosols accumulated at night, and the aerosol extinction could reach 1.3 km-1 in the morning. The aerosol variations in Hefei and Nanjing were consistent due to the relative conformity of the surrounding environmental conditions (R = 0.84). The vertical distribution of aerosol in all three cities had the same Gaussian shape. The aerosol lifted layers in Nanjing and Shanghai were higher than that in Hefei, with heights of 0.2-0.8 km and 0.2-0.6 km, respectively. The averaged aerosol extinctions for these two cities were 0.34 km-1 and 0.49 km-1, respectively. Pollution source analysis was conducted based on wind field trajectory, satellite observation, and model simulation, taking Hefei as the recipient. The results showed that western Shandong Province, northern Anhui Province, northern Jiangxi Province, central Jiangsu Province, and the central YRD were the most important aerosols sources for Hefei. The contributions of central and southern Jiangsu Province were significantly higher than those of other potential sources, with a WCWTAOD (Meteoinfo concentration weight trajectory) between 1.2 and 3.0. The influence of fine particles produced by open biomass burning inside the YRD was significantly higher than that outside the region (outside contribution: 36.6 %). Regarding the influence between YRD cities, more aerosols were transported from Shanghai to Hefei and Nanjing, with similar transport contributions between Nanjing and Hefei.

Proteomics of restenosis model in LDLR-deficient hamsters coupled with the proliferative rat vascular smooth muscle cells reveals a new mechanism of vascular remodeling diseases.

A major pathological mechanism involved in vascular remodeling diseases is the proliferation and migration of vascular smooth muscle cells. The lipid distribution of golden hamsters is similar to that of humans, which makes them an excellent study model for studying the pathogenesis and molecular characteristics of vascular remodeling diseases. We performed proteomic analysis on Sprague Dawley rat VSMCs (rVSMCs) and restenosis hamsters with low-density lipoprotein receptor (LDLR) deficiency as part of this study. We have also performed the enrichment analysis of differentially modified proteins in regards to Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein domain. 1070 differentially abundant proteins were assessed in rVSMCs before and after platelet-derived growth factor-BB (PDGF-BB) stimulation. Specifically, 1246 proteins displayed significant differences in the restenosis model in LDLR-deficient hamsters. An analysis of crosstalk between LDLR+/- hamsters artery restenosis and proliferating rVSMCs revealed 130 differentially expressed proteins, including 67 up-regulated proteins and 63 downregulated proteins. Enrichment analysis with KEGG showed differential proteins to be mainly concentrated in metabolic pathways. There are numerous differentially abundant proteins but particularly two proteins (phosphofructokinase 1 of liver type and lactate dehydrogenase A) were found to be up-regulated by PDGF-BB stimulation of rVSMCs and in a restenosis model of hamsters with LDLR+/- expression. SIGNIFICANCE: Based on bioinformatics, we have found glycolysis pathway plays an important role in both the LDLR+/- hamsters restenosis model and the proliferation of rVSMCs. Some key glycolysis enzymes may likely be developed either as new biomarkers or drug targets for vascular remodeling diseases.

Vertical characteristics of NO2 and HCHO, and the ozone formation regimes in Hefei, China.

The research on the mechanism of combined air pollution in the Yangtze-Huaihe region, which is characterized by unique meteorological and geographical conditions and pollution emission characteristics, is still insufficient. We performed an experiment on key pollutants and an ozone formation study in Hefei, which is a pivotal city in the Yangtze-Huaihe region, from September 1 to 20, 2020. The aerosols retrieved via two-dimensional Multi-axis Differential Optical Absorption Spectroscopy (2D-MAX-DOAS) with a Boltzmann-shaped a priori profile had the best agreement with the results of Light Detection and Ranging (LIDAR) and sun-photometer measurements among the three typical a priori profiles (Gaussian, Boltzmann, and exponential shapes). The correlation coefficients of the near-surface gas concentrations retrieved using both 2D-MAX-DOAS and in situ measurements were 0.86 (NO2) and 0.61 (HCHO). The high NO2 and HCHO concentrations were observed at azimuths of 180° and 315° at heights of 0.8-1.5 km, and they may have been emitted by aircrafts. Importantly, the ratio of HCHO to NO2 during a typical pollution episode revealed that the factors controlling the O3 formation changed with altitude: VOCs (surface) to NOx (0.4 km) to transition (1.0 km) to VOCs (1.6 km). Moreover, the effect of VOCs on the O3 generation was stronger than that of NOx, especially in the downtown area of Hefei. When the ratio of HCHO to NO2 was 3.55-7.46, the ozone concentration in Hefei could be controlled well, especially at the optimal value of 5.50.

Mitophagy-Mediated mtDNA Release Aggravates Stretching-Induced Inflammation and Lung Epithelial Cell Injury via the TLR9/MyD88/NF-κB Pathway.

BACKGROUND: In animal models of ventilation-induced lung injury, mitophagy triggers mitochondria damage and the release of mitochondrial (mt) DNA, which activates inflammation. However, the mechanism of this process is unclear. METHODS: A model of cyclic stretching (CS)-induced lung epithelial cell injury was established. The genetic intervention of phosphatase and tensin homolog-induced kinase 1 (PINK1) expression via lentivirus transfection was used to identify the relationship between PINK1-mediated mitophagy and mtDNA release in stretching-induced inflammatory response and injury. Pharmacological inhabitation of Toll-like receptor 9 (TLR9) and myeloid differentiation factor 88 (MyD88) expression was performed via their related inhibitors, while pre-treatment of exogenous mtDNA was used to verify the role of mtDNA in stretching-induced inflammatory response and injury. RESULTS: Using a cell culture model of CS, we found that knocking down PINK1 in lung epithelial cells reduced mitophagy activation and mtDNA release, leading to milder inflammatory response and injury; conversely, up-regulating PINK1 exacerbated stretching-induced inflammation and injury, and similar effects were observed by upregulating TLR9 to induce expression of MyD88 and nuclear factor-κB (NF-κB)/p65. Down-regulating MyD88 protected lung epithelial cells from stretching injury and decreased NF-κB/p65 expression. CONCLUSION: These findings suggest that PINK1-dependent mitophagy and associated TLR9 activation is indeed a major factor in stretch-induced cell injury via a mechanism in which released mtDNA activates TLR9 and thereby the MyD88/NF-κB pathway. Inhibiting this process may be a therapeutic approach to prevent inflammation and cell injury in patients on mechanical ventilation.

Clinical impact of type 2 diabetes mellitus on outcomes after one-lung ventilation during thoracic surgery: a retrospective cohort study.

BACKGROUND: The preoperative presence of diabetes mellitus (DM) has been recently demonstrated to be a risk factor for adverse events after thoracic surgery. However, the specific effects of presence of DM preoperatively on thoracic surgery is not known. This study aimed to investigate the association between preoperative DM and clinical outcomes and the short-term survival rates after thoracic surgery. METHODS: In this retrospective, observational, and matched-pair analysis study, patients receiving thoracic surgery from a tertiary university hospital in 2 consecutive years were grouped as either type 2 DM (T2DM) or controlled within the first 24 hours after surgery. Multivariate Cox regression was conducted to investigate the impact of T2DM within the first 24 hours of admission on in-intensive care unit (ICU) and hospital survival. RESULTS: Among the included thoracic patients, 41 (8.4%) had T2DM and 450 (91.6%) did not have T2DM. In the single-factor analyses, T2DM patients were shown to have a higher preoperative white blood cells (WBCs) count, increased release of immunoglobulin A, complement C3 and C4, impaired kidney function with high level of urea, and low expression of alanine aminotransferase (ALT) and monoamine oxidase (MAO). In multivariate analyses, the preoperative urea level was associated with a low-grade risk of dying for the ICU survival time. In contrast, preoperative complement C3 level favored a positive contribution in-ICU survival. Besides the complement C3 level, immunoglobulin A level remained a positive contribution in regression models of hospital survival. CONCLUSIONS: Pre-admission T2DM was not associated with an increased in-ICU and hospital mortality among patients with thoracic surgery. Furthermore, they were accompanied by impaired kidney function, activated inflammation and liver function.

Pinpointing nitrogen oxide emissions from space.

Satellite observations of nitrogen dioxide (NO2) provide valuable information on the location and strength of NO x emissions, but spatial resolution is limited by horizontal transport and smearing of temporal averages due to changing wind fields. In this study, we map NO x emissions on high spatial resolution from TROPOMI observations of NO2 combined with wind fields based on the continuity equation. The divergence of horizontal fluxes proves to be highly sensitive for point sources like exhaust stacks. Thus, NO x emissions from individual power plants can be resolved and quantified even on top of considerably high urban pollution from the Saudi Arabian capital city Riyadh. This allows us to catalog NO x emissions from large point sources globally, as demonstrated for South Africa and Germany, with a detection limit of about 0.11 kg/s down to 0.03 kg/s for ideal conditions.

Non-intubated anesthesia in patients undergoing video-assisted thoracoscopic surgery: A systematic review and meta-analysis.

INTRODUCTION: Non-intubated anesthesia (NIA) has been proposed for video-assisted thoracoscopic surgery (VATS), although how the benefit-to-risk of NIA compares to that of intubated general anesthesia (IGA) for certain types of patients remains unclear. Therefore, the aim of the present meta-analysis was to understand whether NIA or IGA may be more beneficial for patients undergoing VATS. METHODS: A systematic search of Cochrane Library, Pubmed and Embase databases from 1968 to April 2019 was performed using predefined criteria. Studies comparing the effects of NIA or IGA for adult VATS patients were considered. The primary outcome measure was hospital stay. Pooled data were meta-analyzed using a random-effects model to determine the standard mean difference (SMD) with 95% confidence intervals (CI). RESULTS AND DISCUSSION: Twenty-eight studies with 2929 patients were included. The median age of participants was 56.8 years (range 21.9-76.4) and 1802 (61.5%) were male. Compared to IGA, NIA was associated with shorter hospital stay (SMD -0.57 days, 95%CI -0.78 to -0.36), lower estimated cost for hospitalization (SMD -2.83 US, 95% CI -4.33 to -1.34), shorter chest tube duration (SMD -0.32 days, 95% CI -0.47 to -0.17), and shorter postoperative fasting time (SMD, -2.76 days; 95% CI -2.98 to -2.54). NIA patients showed higher levels of total lymphocytes and natural killer cells and higher T helper/T suppressor cell ratio, but lower levels of interleukin (IL)-6, IL-8 and C-reactive protein (CRP). Moreover, NIA patients showed lower levels of fibrinogen, cortisol, procalcitonin and epinephrine. CONCLUSIONS: NIA enhances the recovery from VATS through attenuation of stress and inflammatory responses and stimulation of cellular immune function.

[Effect of high tidal volume mechanical ventilation on pulmonary autophagy and mitochondrial damage in rats].

OBJECTIVE: To investigate the relationship between different tidal volume (VT) mechanical ventilation (MV) and autophagy and mitochondrial damage in rats. METHODS: A total of 120 clean-grade male Sprague-Dawley (SD) rats were divided into five groups (n = 24) by random number table method, and then given 0 (spontaneous breathing), 10, 20, 30, 40 mL/kg VT for MV. The rats in each group were subdivided into four subgroups of 1, 2, 3, and 4 hours according to ventilation time, with 6 rats in each subgroup. The lung tissue and bronchoalveolar lavage fluid (BALF) were harvested, and alveolar macrophages (AMs) and type II alveolar epithelial cells (AEC II) were cultured in vitro. The mRNA and protein expressions of autophagy-associated protein microtubule-associated protein 1 light chain 3B-II (LC3B-II) and autophagy-related genes Beclin1 and p62 were determined by reverse transcription-polymerase chain reaction (RT-PCR) or Western Blot. Lung autophagosome formation was observed under transmission electron microscope. The levels of adenosine triphosphate (ATP), reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in lung tissue were determined for assessing mitochondrial damage. RESULTS: There were no significant differences in the mRNA and protein expressions of LC3B-II, p62 and Beclin1 at 1 hour after ventilation among the groups. With the prolonged ventilation time, the mRNA and protein expressions of LC3B-II, p62 and Beclin1 in MV groups were increased gradually, peaked at 2-3 hours, and they were increased significantly in 30 mL/kg VT group as compared with those in spontaneous respiration group with statistical significances [ventilation for 2 hours: LC3B-II mRNA (2-ΔΔCt) was 2.44±0.24 vs. 1.12±0.04, LC3B-II/LC3B-I was 1.42±0.16 vs. 0.57±0.03, p62 mRNA (2-ΔΔCt) was 2.96±0.14 vs. 1.14±0.02, Beclin1 mRNA (2-ΔΔCt) was 2.80±0.13 vs. 1.14±0.02; ventilation for 3 hours: p62/ß-actin was 1.14±0.15 vs. 0.55±0.04, Beclin1/ß-actin was 1.27±0.06 vs. 0.87±0.04, all P < 0.05]. Autophagosomes and autolysosomes were found in AEC II after ventilation for 2 hours at 30 mL/kg VT by transmission electron microscopy, but not in AEC I. Compared with spontaneous breathing group, ATP synthesis in AMs was significantly decreased at 2 hours of ventilation in 30 mL/kg VT group (A value: 0.82±0.05 vs. 1.00±0.00, P < 0.05), ROS accumulate in AMs and AEC II were significantly increased [ROS in AMs: (33.83±4.00)% vs. (6.90±0.62)%, ROS in AEC II: (80.68±0.90)% vs. (2.16±0.19)%, both P < 0.05]. With the increase in VT and the prolongation of ventilation time, ATP and ROS levels in AMs and AEC II were gradually decreased, the ATP (A value) in AMs at 4 hours of ventilation in 40 mL/kg VT group was 0.41±0.05, the ROS in AMs was (12.95±0.88)%, and the ROS in AEC II was (40.43±2.29)%. With the increase in VT and the prolongation of ventilation time, MMP levels were gradually increased, the MMP (green/red fluorescence intensity ratio) in AMs at 2 hours of ventilation in 30 mL/kg VT group was 1.11±0.17, the MMP in AEC II was 0.96±0.04, and the MMP (green/red fluorescence intensity ratio) at 4 hours of ventilation in 40 mL/kg VT group was 0.51±0.07 and 0.49±0.06, respectively. CONCLUSIONS: The MV with high VT could induce autophagy activation and mitochondrial damage in lung tissue of rats, and the longer the ventilation time, the more obvious autophagy in the lung.

Long-term observations of tropospheric NO2, SO2 and HCHO by MAX-DOAS in Yangtze River Delta area, China.

Yangtze River Delta (YRD) area is one of the important economic zones in China. However, this area faces increasing environmental problems. In this study, we use ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) network in Eastern China to retrieve variations of NO2, SO2, and formaldehyde (HCHO) in the YRD area. Three cities of YRD (Hefei, Nanjing, and Shanghai) were selected for long-term observations. This paper presents technical performance and characteristics of instruments, their distribution in YRD, and results of vertical column densities (VCDs) and profiles of NO2, SO2, and HCHO. Average diurnal variations of tropospheric NO2 and SO2 in different seasons over the three stations yielded minimum values at noon or in the early afternoon, whereas tropospheric HCHO reached the maximum during midday hours. Slight reduction of the pollutants in weekends occurred in all the three sites. In general trace gas concentrations gradually reduced from Shanghai to Hefei. Tropospheric VCDs of NO2, SO2, and HCHO were compared with those from Ozone Monitoring Instrument (OMI) satellite observations, resulting in R2 of 0.606, 0.5432, and 0.5566, respectively. According to analysis of regional transports of pollutants, pollution process happened in YRD under the north wind with the pollution dissipating in the southeast wind. The feature is significant in exploring transport of tropospheric trace gas pollution in YRD, and provides basis for satellite and model validation.

Microvesicles packaging IL-1ß and TNF-α enhance lung inflammatory response to mechanical ventilation in part by induction of cofilin signaling.

Microvesicles shed from pulmonary cells are capable of transferring inflammatory cargo to recipient cells nearby or in distant to enhance inflammation. Some authors believe that cofilin controls actin dynamics and regulates vesicle mobilization. We therefore investigated the potential role and mechanism of microvesicles in ventilator-induced lung injury (VILI). Fifty male C57BL/6 mice were orotracheally intubated and either allowed to breathe spontaneously or they were mechanically ventilated with different tidal volumes (Vt) and ventilation times. Lung tissue injury was assessed in terms of lung histopathologic examination, wet/dry weight ratios, and levels of total proteins and of cytokines. Microvesicle characteristics, sizes, contents and levels as well as cofilin were also measured. We found that lung inflammation increased significantly after ventilation with high Vt for 4 h; these conditions led to secretion of larger and more microvesicles into the alveoli than animals with/without ventilation at low Vt. Intratracheal instillation of microvesicles obtained from animals ventilated with low or high Vt triggered significant lung inflammation in naive mice, and these high-Vt microvesicles not only carried more IL-1ß and TNF-α but also induced more severe lung inflammation compared to low-Vt microvesicles; And high-Vt microvesicles at 2 h carried more molecular cargo than that at 1 h or 4 h, which may involve the shift and amplification of inflammation. Furthermore, blocking the phosphorylation of cofilin can not only inhibit microvesicle formation in the lung, but also reduce lung injury. Collectively, our data suggest that microvesicles packaging IL-1ß and TNF-α enhance lung inflammation in VILI.

Emission Flux Measurement Error with a Mobile DOAS System and Application to NOx Flux Observations.

Mobile differential optical absorption spectroscopy (mobile DOAS) is an optical remote sensing method that can rapidly measure trace gas emission flux from air pollution sources (such as power plants, industrial areas, and cities) in real time. Generally, mobile DOAS is influenced by wind, drive velocity, and other factors, especially in the usage of wind field when the emission flux in a mobile DOAS system is observed. This paper presents a detailed error analysis and NOx emission with mobile DOAS system from a power plant in Shijiazhuang city, China. Comparison of the SO2 emission flux from mobile DOAS observations with continuous emission monitoring system (CEMS) under different drive speeds and wind fields revealed that the optimal drive velocity is 30-40 km/h, and the wind field at plume height is selected when mobile DOAS observations are performed. In addition, the total errors of SO2 and NO2 emissions with mobile DOAS measurements are 32% and 30%, respectively, combined with the analysis of the uncertainties of column density, wind field, and drive velocity. Furthermore, the NOx emission of 0.15 ± 0.06 kg/s from the power plant is estimated, which is in good agreement with that from CEMS observations of 0.17 ± 0.07 kg/s. This study has significantly contributed to the measurement of the mobile DOAS system on emission from air pollution sources, thus improving estimation accuracy.