[Analysis of Seasonal Variations in Chemical Characteristics and Sources of PM2.5 During Summer and Winter in Ji'nan City].

To investigate seasonal variations in the chemical compositions of aerosols in Ji'nan City, PM2.5 samples were collected during summer and winter in 2015. The sampling period lasted one month during each season. PM2.5 samples were analyzed for the composition, concentration, and sources of water-soluble inorganic ions, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC). Results showed that mass concentrations of PM2.5 in winter were about twice those in summer, and concentration levels varied between fine and excellent. The concentrations of total water-soluble inorganic ions were also higher in winter than in summer, with SO42-, NO3-, and NH4+ being the dominant species and well correlated with each other. NH4+ in PM2.5 mostly existed in the form of (NH4)2SO4 and NH4NO3 in both summer and winter. There was strong secondary oxidation of SO2 and NO2. The sulfate oxidizing rate (SOR) was higher in summer than in winter, while the nitrate oxidizing rate (NOR) showed the opposite trend. The ratio of anions to cations in both summer and winter were less than one, suggesting that PM2.5 were slightly alkaline. The ISORROPIA-Ⅱ mode showed that acidity in winter was stronger than in summer. Concentations of OC and EC were both higher in winter than in summer. The ratios of OC to EC and WSOC to OC and estimated concentrations of secondary organic carbon (SOC) showed that secondary pollution was more serious in winter than in summer. Principal component analysis(PCA)indicated that the major sources contributing to inorganic ions were secondary oxidation and biomass burning in summer, and coal combustion and secondary pollutants formed by chemical oxidation of precursors emitted from coal combustion in winter.

[Diurnal Variation of Dicarboxylic Acids and Related SOA in PM2.5 from Heze City in Winter].

To identify the diurnal variation and formation mechanism of dicarboxylic acids and related compounds in PM2.5 from Heze City, PM2.5 samples were collected in the winter (December) of 2017, which were subsequently analyzed for dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, and levoglucosan (Levo). The results showed that the total concentrations of dicarboxylic and ketocarboxylic acids were higher during daytime than those during nighttime. In contrast to the diurnal variation of dicarboxylic and ketocarboxylic acids, the total concentrations of α-dicarbonyls exhibited higher concentrations in nighttime than in daytime. Because α-dicarbonyls are the major precursors of dicarboxylic acids, the opposing patterns suggest that the photochemical oxidation in daytime is stronger than that in nighttime. Oxalic acid (C2) is the dominant species during both day-and nighttime, followed by phahalic acid (Ph), succinic acid (C4), and malonic acid (C3), which is consistent with that in other urban regions. The mass ratios of C3/C4 (R2>0.7) correlated strongly with temperature, indicating that organic compounds in the atmosphere of Heze City are mainly derived from the photochemical oxidation of local emissions rather than long-range transport in winter. C2 correlated with in-situ pH and SO42-, suggesting that aqueous-phase oxidation was the major formation pathway of C2, which is driven by acid-catalyzed oxidation. Since the major SOA (C2, glyoxal, and methyglyoxal, secondary organic aerosol) correlated with Levo and the average mass rations of K+/organic carbon was 0.06 (ranging from 0.03 to 0.13), it can be concluded that the dicarboxylic acids and related SOA and K+ in Heze City were significantly influenced by biomass burning in winter.

[Compositions and Sources of Summertime Dicarboxylic Acids and Related SOA in PM2.5 from Mt. Taishan].

To identify the compositions and sources of dicarboxylic acids and related SOA in Mt. Taishan, PM2.5 samples were collected from July to August, 2004, and analyzed for dicarboxylic acids and related compounds, the tracers of biogenic secondary organic aerosol (SOA) (Isopene, α-/ß-Pinene and ß-caryophyllene SOA tracers), water-soluble organic carbon (WSOC) and inorganic ions. The results showed that total dicarboxylic acids were (376±189) ng·m-3, and C2 was the most abundant dicarboxylic acid, followed by C3, C4 and C9. The concentrations of diacids were more abundant than those in marine regions, but lower than those in urban and other mountainous areas, indicating that the atmosphere in Mt. Taishan was less influenced by anthropogenic pollution. C2/C4, C3/C4 and F/M ratios indicated that diacids were mostly produced by more intensive photochemical oxidation. The relative abundance of C9 to the total diacids, C9/C6 and C9/Ph ratios were higher than those in urban, marine and mountainous regions, further suggesting that SOA in Mt. Taishan atmosphere were mostly derived from biogenic sources rather than anthropogenic sources. Compared to the budgets of model and correlation analysis, it suggested that diacids and related SOA in Mt. Taishan were mostly derived from photochemical oxidation of local biogenic sources.

[Seasonal Variation and Sources of Dicarboxylic Acids and Related Compounds in PM10 from Mt. Huangshan].

To identify the seasonal variation of dicarboxylic acids and related compounds in PM10 from Mt. Huangshan. PM10samples were collected during the summer and winter of 2015, which were then analyzed for dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls. The results showed that oxalic acid(HOOC-COOH, C2) was the dominant species in the summer and winter months, followed by malonic acid(HOOC-CH2-COOH, C3), and succinic acid[HOOC-(CH2)2-COOH, C4], being consistent with that in other high-altitude regions. Most of the diacids were more abundant in the summer months than in the winter months, while adipic acid(C6) and phahalic acid(Ph) were twice lower in the summer months, suggesting significant impact of anthropogenic pollution on the wintertime alpine atmosphere. Moreover, as major precursors of C2, glyoxal(Gly) and methylglyoxal(mGly) were also lower in the summer months than in the winter months, which were opposite to those of the diacids, indicating that the mountain troposphere was more oxidative in the summer months than in the winter months. Principal component analysis(PCA) further revealed that the wintertime SOA in the Mt. Huangshan troposphere mostly originated from the anthropogenic pollutants from long-distance transport. Conversely, the summertime SOA mostly originated from the further oxidation of the mountainous biogenic sources. The AIM(Aerosol Inorganic Model) calculation results showed that the aqueous-phase C2 production was the primary mechanism of C2 formation in ambient aerosol and was driven by acid-catalyzed oxidation in summer.

Brachiocephalic trunk and left brachiocephalic vein injuries following penetrating right sternoclavicular junction trauma: a case report / 中华创伤杂志(英文版)

A 46-year-old male sustained severe pe- netrating injury by a sharp instrument to his right upper sternoclavicular junction. The wound tract was from suprasternal notch to mediastinum. Exploratory operation via median sternotomy under general anesthesia found a large mediastinal septum hematoncus, as well as brachiocephalic trunk and left brachiocephalic vein injuries. The perforating vascular wounds were repaired with 5-0 prolene suture. He was recovered uneventfully and discharged 9 days after operation. There was no sequel found during 7 years follow-up.

Use of bronchofiberscopy in management of severe thoracic trauma / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the diagnostic and therapeutic effect of bronchofiberscopy in the management of severe thoracic trauma.</p><p><b>METHODS</b>A retrospective study was conducted on 207 consecutive patients with severe thoracic trauma enrolled in our hospital between January 2008 and June 2012. During the period, 488 bronchofiberscopies and lavages were done. The bronchofiberscope was inserted through tracheal incision (282), nasal cavity (149) and oral cavity (57). Intensive SaO2 monitoring as well as blood gas analysis were performed pre-, intra- and postoperatively. Simultaneously oxygen therapy or ventilatory support was given. Sputum culture was done intraoperatively.</p><p><b>RESULTS</b>Diagnosis in 207 cases was confirmed by bronchofiberscopy. The result of sputum culture was positive in 78 cases. Lavage was performed on 156 cases. SaO2 significantly increased after bronchofiberscopies as well as lavages and PaO2 obviously improved 2 h after surgery (both P less than 0.05). Heart rate and respiratory rate decreased. There was no bronchofiberscopy-related death.</p><p><b>CONCLUSION</b>Bronchofiberscopy plays an important role in the diagnosis and treatment of severe thoracic trauma, which can not only timely diagnose bronchial injury and collect deep tracheal sputum for bacterial culture but also effectively remove foreign body, secretion, blood and sputum crust in the airway, manage obstructive atelectasis and pneumonia, and significantly improve respiratory function and treatment outcome.</p>

Analysis on care outcome of patients with polytrauma and coma / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To make further improvement of outcome of patients with polytrauma and coma.</p><p><b>METHODS</b>The data of 3361 patients (2378 males and 983 females, aged from 5-95 years, 38.2 years on average) with severe polytrauma and coma admitted to Chongqing Emergency Medical Center (Level I Trauma Center), Chongqing, China, from November 1978 to December 2004 were analyzed retrospectively in this study.</p><p><b>RESULTS</b>The overall survival rate and mortality were 93.2% (3133/3361) and 6.8% (228/3361), respectively. The mortalities in patients with coma duration less than 1 hour and combined with neural dysfunction and in patients with coma duration larger than or equal to 1 hour and combined with or without neural dysfunction were significantly higher than that of those with coma duration less than 1 hour but without neural dysfunction [39.5% (136/344) vs 3.0% (92/3017), P less than 0.01]. There existed significant differences in GCS, ISS, and revised trauma score (RTS) between the death group and the survival group (P less than 0.01). RTS was in good correspondence with patient's pathophysiological status and outcome in patients with multiple trauma and coma for different groups of systolic blood pressure (SBP). The mortality in patients with SBP less than 90 mm Hg was significantly higher than that of those with SBP larger than or equal to 90 mm Hg [33.3% (68/204) vs 5.1% (160/3157), P less than 0.01]. The mortality in polytrauma patients combined with serious head injury (AIS larger than or equal to 3) was 8.2%, among which, 76.5% died from lung complications. The morbidity rate of lung complications and mortality rate increased in patients with head injury complicated with chest or abdomen injury (23.9%, 61.1% vs 27.3%, 50.0%). The mortality reached up to 61.9% in patients complicated with severe head, chest and abdomen injuries simultaneously.</p><p><b>CONCLUSIONS</b>It plays a key role to establish a fast and effective trauma care system and prompt and definite surgical procedures and to strengthen the management of complications for improving the survival rate of patients with severe polytrauma and coma.</p>