Solvent Vehicle Research Articles

Summertime ozone pollution in Sichuan Basin, China: Meteorological conditions, sources and process analysis

The Sichuan Basin (SCB) has suffered from serious ozone (O3) pollution in recent years, especially in summer. However, the formation and evolution mechanisms of O3 pollution in the SCB remain poorly understood. In this paper, we comprehensively investigated the causes of elevated ozone concentrations in Chengdu in July 2017 with a combination of field measurements and the WRF (Weather Research and Forecasting)-CMAQ (Community Multi-scale Air Quality) model simulations. The ozone formation characteristics of continuous O3 episodes and non-O3 episodes were compared. Higher temperature (T), stronger solar radiation (SR), lower relative humidity (RH) and weaker winds were conducive to O3 formation during ozone episodes. The O3 concentration during O3 episodes (202.6 μg m−3) was significantly higher than that during non-O3 episodes (122.7 μg m−3), attributable to the higher volatile organic compounds (VOCs) concentration (34.0 ppbv compared with 27.5 ppbv) despite comparable NOx concentrations during O3 episodes. The results of positive matrix factorization (PMF) for ambient VOCs showed that gasoline vehicle exhaust and solvent usage were the dominant sources during the month. However, the increasing source attributions from the petrochemical industry and biogenic emissions were responsible for the elevated VOCs concentrations during O3 episodes. The relative contributions of local emission and regional transport to ozone were quantified during two O3 episodes by conducting numerical sensitivity experiments. In the first episode, namely, the “O3-regionally transported” pattern, high ozone concentration in Chengdu was primarily due to the regional transport of ozone and ozone precursors through vertical mixing and horizontal advection from upwind areas (central and eastern SCB) when easterly or southeasterly winds prevailed over the SCB. In contrast, in the second episode, namely, the “O3-locally dominated” pattern, high local emissions under favorable meteorological conditions are the major reason for elevated ozone concentration. The process analysis results from the CMAQ model suggested that the vertical transport of O3 that formed at the upper levels from intense gas-phase chemistry reactions was a dominant contributor to diurnal O3 enhancement in O3 episodes by 45 μg m−3, while horizontal transport contributed more than 80% of the nocturnal O3 concentration. This study provides a better understanding of ozone photochemical formation and regional transport mechanisms in the SCB under complex terrain conditions, and contributes to ozone pollution prevention in other basins around the world.

Chronic inhibition of phosphodiesterase 5 with tadalafil affords cardioprotection in a mouse model of metabolic syndrome: role of nitric oxide.

Patients with metabolic syndrome (MetS) often exhibit generalized endothelial and cardiac dysfunction with decreased nitric oxide (NO) production and/or bioavailability. Since phosphodiesterase 5 (PDE5) inhibitors restore NO signaling, we hypothesized that chronic treatment with long-acting PDE5 inhibitor tadalafil may enhance plasma NO levels and reduce cardiac dysfunction following ischemia/reperfusion (I/R) injury in C57BL/6NCrl-Leprdb-lb/Crl mice with MetS phenotypes. Adult male MetS mice were randomized to receive vehicle solvent or tadalafil (1mg/kg,i.p.) daily for 28days and C57BL/6NCrl mice served as healthy wild-type controls. After 28days, cardiac function was assessed by echocardiography and hearts from a subset of mice were isolated and subjected to 30min of global ischemia followed by 60min of reperfusion (I/R) in ex vivo Langendorff mode.Body weight, blood lipids, and glucose levels were elevated in MetS mice as compared with wild-type controls. The dyslipidemia in MetS was ameliorated following tadalafil treatment. Although left ventricular (LV) systolic function was minimally altered in the MetS mice, there was a significant diastolic dysfunction as indicated by reduction in the ratioof peak velocity of early to late filling of the mitral inflow, which was significantly improved by tadalafil treatment. Post-ischemic cardiac function, heart rate, and coronary flow decreased significantly in MetS mice compared to wild-type controls, but preserved by tadalafil treatment. Myocardial infarct size was significantly smaller following I/R, which was associated with higher plasma levels of nitrate and nitrite in the tadalafil-treated MetS mice. In conclusion, tadalafil induces significant cardioprotective effects as shown by improvement of LV diastolic function, lipid profile, and reduced infarct size following I/R. Tadalafil treatment enhanced NO production, which may have contributed to the cardioprotective effects.

Analysis of Pollution Characteristics and Sources of Atmospheric VOCs in Ezhou City

From March 2018 to February 2019, quantitative detection was made of 102 kinds of atmospheric volatile organic compounds (VOCs) using online gas chromatography in Ezhou City. We compared and analyzed the composition, seasonal variation, and diurnal variation of VOCs. Using maximum incremental reactivity (MIR), we estimated the ozone generation potential (OFP) of VOCs. The results show that the annual average volume fraction of atmospheric VOCs in Ezhou is (30.78±15.89)×10-9, and is overall higher in winter than summer, represented by alkane > oxygen > halogenated hydrocarbon > olefin > aromatic hydrocarbon > alkyne. The night volume fraction is higher than in the daytime, and overall the distribution is "double peak". The aromatic hydrocarbons, halogenated hydrocarbons, and OVOCs appear as a "third peak" at 00:00-02:00. Aromatic hydrocarbons and olefins contribute more to the OFP potential of VOCs, with contribution rates of 35.45% and 29.5%, respectively. The highest contribution rate to OFP is ethylene, reaching 24.217%. Analysis of VOC characteristic species found that vehicle exhaust fumes and solvent volatilization are the main sources of VOCs in Ezhou. Of these, motor vehicle emissions are the most important source. Controlling Ezhou's motor vehicle emissions helps to reduce the composition of atmospheric VOCs, thereby reducing ozone production.

Source apportionment of atmospheric volatile aromatic compounds (BTEX) by stable carbon isotope analysis: A case study during heating period in Taiyuan, northern China

Due to the high negative effects on health and environment, volatile aromatic compounds (benzene, toluene, ethylbenzene and xylene, BTEX) have drawn more and more attention recently. BTEX samples of four emission sources (coal combustion, vehicle exhaust, gasoline volatilization and solvent evaporation) and ambient air from three sampling sites (rural, urban and suburban) were collected during winter in Taiyuan, northern China. Gas chromatography–mass spectrometry and thermal desorption–gas chromatography–isotope ratio mass spectrometry were employed to investigate the composition characteristics and stable carbon isotopic (δ13C) analysis of BTEX, respectively. The results revealed that the δ13C value of BTEX for coal combustion, with the range of −23.8‰ to −25.2‰, was higher than that for vehicle exhaust, gasoline volatilization and solvent evaporation, ranging from −25.5‰ to −27.6‰, −28.0‰ to −30.9‰ and −27.7‰ to −32.1‰, respectively. Atmospheric BTEX concentrations were the highest at the suburban site (41.5 μg/m3) and the lowest at the rural site (27.0 μg/m3). The δ13C values of atmospheric BTEX at rural, urban and suburban sites ranged from −24.8‰ to −26.2‰ (average −25.3‰), −24.8‰ to −26.9‰ (average −26.0‰) and −23.9‰ to −25.4‰ (average −24.8‰), respectively, indicating that the suburban site was enriched in 13C relative to rural and urban sites. The B/T ratio results indicated that coal combustion was the primary source of atmospheric pollution in Taiyuan. The mean contribution of emission sources in all three sampling site were determined by adopting Isosource-based quantitative calculation. For rural, urban and suburban sites, coal combustion, as the major source, made mean contributions of 62.3%, 46.0% and 74.1%, while vehicle exhaust was responsible for 22.0%, 30.6% and 15.3%, respectively. Coal combustion and vehicle exhaust were the top two primary sources of BTEX in Taiyuan, especially coal combustion provided a half contribution to atmospheric BTEX. Therefore, implementing controls on coal combustion is crucial to reduce ambient volatile aromatic compound pollution, especially in areas with high coal consumption.

Distribution, Sources, and Health Risk Assessment of Volatile Organic Compounds in Hefei City.

Volatile organic compounds (VOCs) are involved in the formation of ozone formation, which plays a significant role in regional air contamination and poses a great threat to human health. The VOCs were collected from the urban area of Hefei city via an off-line sampling method (SUMMA canister) and determined by gas chromatography-mass spectrometer. The average concentrations of VOCs were 17.65 ± 28.36 ppbv, which were mainly contributed by aromatics (10.02 ± 13.37 ppbv), haloalkane (5.37 ± 8.90 ppbv), ally halide (1.25 ± 3.36 ppbv), and aryl halid (1.02 ± 2.73 ppbv). According to the principal component analysis, three major sources were identified, including solvent use, vehicle exhaust, and industrial release, accounting for 70.6% of the total variance of the data. Health risk assessment was utilized to evaluate the potential adverse health effects of the individual VOC. The total hazard ratio in the selected area was higher than 1, where could pose health threat to exposed population. The cancer risk for benzene, carbon tetrachloride, trichloromethane, and 1, 2-dichloroethane were 4.8 × 10-5, 4.5 × 10-5, 3.3 × 10-5, and 2.5 × 10-5, respectively, indicating definite health risks.

Prolonged continuous infusion of teriparatide promotes bone metabolism in normal but not in castrated mice

To investigate the effects of continuous pumping of teriparatide (TPTD) on bone metabolism in ovariectomized and normal mice and provide experimental evidence for the selection of animal models for studying the effects of TPTD and its related peptides on osteoclasts. Twenty-four female C57BL mice (6-weeks old) were subjected to ovariectomy (OVX) or sham operation followed 7 days later by continuous pumping of TPTD or the solvent vehicle (VEH) via a micropump (SHAM-VEH, SHAM-TPTD, OVX-VEH, and OVX-TPTD groups; n=6). Two weeks later, the tibial and femoral bones were harvested for micro-CT scanning to measure the parameters of the tibia and the femoral cortical bone. Histopathological examinations of the tibial tissue were conducted using HE staining and TRAP staining and the number of osteoclasts and the growth plate thickness were determined. The serum Ca2 + levels of the mice were measured. The primary osteoblasts from the cranial bone were treated with estradiol (E2) and TPTD for 48 h, and the expressions of β-catenin and RANKL protein in the cells were analyzed. The trabecular bone mass of OVX mice was significantly lower than that of sham-operated mice (P < 0.05). Continuous TPTD pumping significantly reduced tibial cancellous bone mass and femoral cortical bone area in the sham-operated mice, while in the castrated mice, TPTD pumping increased the cancellous bone mass without changing the cortical bone area. TRAP staining showed that cancellous osteoblasts in the tibia increased significantly in the castrated mice as compared with the sham-operated mice, and TPTD pumping significantly increased the number of cancellous osteoblasts in the sham-operated mice (P < 0.05). In the primary cultured osteoblasts, treatment with both E2 and TPTD obviously lowered the expression of β-catenin and increased the expression of RANKL as compared with TPTD treatment alone. Continuous pumping of TPTD promotes bone resorption in normal mice but does not produce obvious bone resorption effect in the ovariectomized mice, suggesting that castrated mice are not suitable models for studying the effect of TPTD and the related peptides on the osteoclasts.

Decreased gaseous carbonyls in the North China plain from 2004 to 2017 and future control measures

Gaseous carbonyls are important precursors of ozone and secondary organic aerosols. To study the characteristics of small-molecule carbonyls (SMC), samples were collected with 2, 4-dinitrophenylhydrazine in Xianghe at the junction of the Beijing, Tianjin and Hebei regions from November 2017 to January 2018 and were subjected to high-performance liquid chromatography-ultraviolet analysis. The mean concentration of SMC was 4.5 ± 1.1 ppbv, and the observed compounds included acetone (1.9 ± 1.3 ppbv), acetaldehyde (1.3 ± 1.0 ppbv) and formaldehyde (1.2 ± 0.9 ppbv). Compared with the observations in the Beijing-Tianjin-Hebei region from 2004 to 2017, the concentration of SMC decreased and the trends were −1.13, −0.44 and −0.45 ppbv yr−1, respectively. Using volatile organic compounds as tracers, positive matrix factorization was used to analyze the sources of the SMC. The results showed that, in addition to secondary and long-lived species (84.8%), the main sources of SMC in Xianghe were vehicle emission (8.5%), solvent usage (3.7%) and coal and biomass combustion (3.0%). The significant decline in the contributions of vehicle emissions, coal and biomass combustion is the main reason for the decline in the SMC concentrations. Based on fine particulate matter concentrations, this study found that with the deterioration in air quality, the contribution of each source changed insignificantly. Although the concentrations of SMC dropped significantly, vehicular sources remained the most important sources in this region.

Characteristics and sources of VOCs in urban and suburban environments in Shanghai, China, during the 2016 G20 summit

To improve air quality for the period of the G20 Hangzhou Summit, comprehensive and stringent emission controls were implemented over the Yangtze River delta region, China. To evaluate the impacts of emission controls on variations of atmospheric volatile organic compounds (VOCs), field measurements of VOCs were conducted at urban and suburban sites in Shanghai from August 24 to September 15, 2016. At both sites, the total budgets of VOCs were determined by alkanes (48.05–57.62%), followed by alkenes (4.74–10.17%), acetylene (0.16–3.90%), and aromatics (32.16–45.64%). As indicated by maximum incremental reactivity methods, aromatics were likely the most important VOCs groups for the ozone formation potential. All of VOCs presented to have significant increases, the maximum rate of change 74.47% at PD and 147.92% at DSL, after the G20 summit were compared with the G20 summit, suggesting the substantial reduction in VOCs due to emission controls over regional scales. Positive matrix factorization analysis of VOCs identified five sources, including petrochemical industry, vehicle exhaust, LPG/NG/fuel vaporization (for suburban the source appended incomplete combustion), solvent usage, organic synthetic materials (only for urban) and plant sources were (only for suburban), at the two sites, respectively. On average, petrochemical industry was the largest contributor (22.11–33.89%) to the total VOCs, followed by vehicle exhaust (22.22–27.27%) and solvent usage (15.01–20.11%). High loadings of VOCs were observed associating with westerly and northerly wind, reflecting the impact of regional transport from surrounding regions on VOCs pollution in Shanghai.

Stable Carbon Isotope Compositions and Source Apportionments of Volatile Aromatic Compounds in the Urban Atmosphere of Taiyuan, China

This study used Tenax TA absorption tubes to sample volatile aromatic compounds from different emission sources and functional zones in Taiyuan City, Shanxi Province, China. Thermal desorption-gas chromatography-isotope ratio mass spectrometry (TD-GC-IRMS) was subsequently employed to analyze the stable carbon isotope characteristics of the volatile aromatic compounds. The results revealed that the stable carbon isotope ratio (δ13C) of the volatile aromatic compounds emitted through diesel, gasoline, and solvent volatilization, vehicle exhaust, and domestic coal combustion ranged from (-30.79±0.98)‰ to (-29.10±0.14)‰, (-30.96±0.88)‰ to (-28.02±1.77)‰, (-32.13±0.59)‰ to (-27.67±0.49)‰, (-27.58±0.16)‰ to (-25.50±0.75)‰, and (-25.14±0.93)‰ to (-23.44±1.32)‰, respectively. The δ13C value of styrene was (-23.44±1.32)‰, which was only detected in the fumes emitted through domestic coal combustion. Additionally, the sample analysis based on data collected from four different functional zones of Taiyuan City revealed the following:① the δ13C values of the atmospheric volatile aromatic compounds in the mixed residential and traffic zone ranged from (-25.61±2.20)‰ to (-23.91±0.78)‰. Compared with other functional zones, the emissions in this zone were enriched with13C; and ② the δ13C values measured in the industrial zone ranged from (-29.15±1.06)‰ to (-24.53±1.07)‰; the emissions in this functional zone were relatively low in 13C compared with other zones. A comparison of the δ13C values of the atmospheric volatile aromatic compounds and emission sources indicated that the main sources of volatile aromatic compounds at the four sampling points in Taiyuan were vehicle exhausts and domestic coal combustion, while the air sampled in the industrial functional zone was heavily affected by the volatilization of solvents.

Celastrus orbiculatus Extracts Inhibit Human Hepatocellular Carcinoma Growth by Targeting mTOR Signaling Pathways.

To characterize the molecular mechanism underlying the antineoplastic activity of Celastrus orbiculatus Thunb. extracts (COE). The human hepatocellular carcinoma HepG2 cells with mammalian target of rapamycin (mTOR) knockdown expressed (HepG2/mTOR) were constructed using molecular biological technology. In vitro, the HepG2/mTOR- cells were treated with COE at various concentrations (10, 20, 40, 80, 160 and 320 µ g/mL). Cell viability was determined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays. According to the half-maximal inhibitory concentration (IC50) value (140 mg/L), the concentrations of COE in the subsequent experiment was set to alleviate cytotoxicity. The HepG2/mTOR- cells were divided into 5 groups: negative control (untreated), COE treatment groups (40, 80, 120 mg/L COE) and positive control group (cisplatin, DDP, 2 mg/L), respectively. Wild-type HepG2 cells were used as a blank control. The effects of COE on the cell apoptosis were analyzed by flow cytometry and transmission electronic microscopy (TEM), respectively. The protein expression levels of mTOR signal pathways were determined by Western blotting. In vivo, HepG2/mTOR- cells (2 × 106 cell/mice) were subcutaneously injected into the right flank of nude mice. Thirty-six female nude mice were randomly assigned to 6 groups according to body weight (6 mice per group) as follows: solvent vehicle control, Banmao Capsule treated group (BM, 195 mg/kg), Tegafur, Gimeracil and Oteracil Potassium Capsules (10 mg/kg) treated group, and different dosages of COE (10, 20, 40 mg/kg) groups. Tumor growth was monitored and immunohistochemical staining was used to examine the expression of apoptosis-related proteins in tumor tissues. COE inhibited the proliferation significantly in a concentration-dependent manner in HepG2/mTOR- cells (P<0.01). COE significantly induced the apoptosis of HepG2/mTOR- cells (P<0.01), and the apoptotic bodies can be observed under TEM. COE significantly inhibits the proteins expression of mTOR-related signal pathways. In vivo, COE significantly inhibited tumor growth in nude mice (P<0.01). Moreover, the results showed that COE down-regulated the expression of Bcl-2 and Bcl-xL, and up-regulated the levels of Bax and caspase-3 protein (P<0.01). COE was a potential chemotherapeutic drug in HCC treatments via targeting mTOR signal pathway.

Formation and characterization of ceramic coating from alumino silicate mineral powders in the matrix of cement composite on the concrete wall

Enhancement of thermal performance of concrete wall is nowadays of great importance in reducing the operational energy demand of buildings. We developed a new kind of inorganic coating material based on \ce{SiO2}-\ce{Al2O3}-rich minerals and Portland cement (PC) powder. The finely pulverized mineral powder with the particle size distribution (PSD) of 0.4-40 $\mu$m was mixed with the vehicle solvent containing some agents, cement powder with PSD of 2-100 $\mu$m, and water in the certain weight ratio, producing the colloid solution. After application within 2 hours to the plaster layer of concrete wall and sufficient long hardening period of over three months, the coating layer of 0.6-1.0 mm thickness was observed to become a densified ceramic. Powder X-ray diffraction (XRD) experiments were performed to identify the crystalline components of minerals, cement and ceramic coating powders. Three- and two-dimensional surface morphologies and chemical compositions of coating material were obtained with the optical interferometer and scanning electron microscope (SEM) equipped with an energy dispersive X-ray analyzer (EDX). These XRD and SEM/EDX analyses demonstrated obviously that the coating layer is mainly composed of the calcium-silicate-hydrate (C-S-H) and the calcium-aluminate-hydrate (C-A-H) ceramics with the relatively small number of closed pores (10\% porosity) compared with the cement mortar and concrete layers. Two-step hydrations of cement and subsequently \ce{SiO2}-\ce{Al2O3} promoted by the alkali product \ce{Ca(OH)2} were proposed as the main mechanism of ceramic formation.

VOC characteristics and source apportionment at a PAMS site near an industrial complex in central Taiwan

Hourly data of volatile organic compounds (VOCs) were collected for three consecutive years from photochemical assessment monitoring stations (PAMS) in Taixi, Taiwan. Analysis of the VOC data allows for apportionment of the anthropogenic sources of VOCs. The VOC concentrations and characteristics were analyzed for temporal variations over a three-year period 2014 to 2016. Out of 54 VOCs detected, 21 VOC compounds from 55 to 99% were below the method detection level; others ranged from 100% occurrence (ethane) to 56–61% for trimethylbenzene. In order to have meaningful statistical results, this paper only used results from 33 VOCs where they were detected at least 65% of the time. This was a requirement to be able to determine statistical parameters such as means and standard deviations. The highest VOC average concentrations observed for three consecutive years, in order, for the period were toluene (3.7–4.3 μg m−3), then propane (2.5–2.6 μg m−3), ethane (2.2–2.5 μg m−3), ethylene (1.1–1.5 μg m−3) and propylene (0.8–1.1 μg m−3). A positive matrix factorization (PMF) receptor model was used to evaluate VOC sources in the area. Six factors were identified by PMF analysis, including solvent use, vehicle exhaust, diesel exhaust, petrochemical, refinery and aged air mass. The conditional probability function indicates that the VOCs in six factors were emitted from their source locations via different wind directions. The contribution of the northwest industrial complex to the PAMS data is linked to the VOCs observed. Actually, seasonal wind directions having only north and north-northwest directions played an important role.

In vivo miRNA delivery in whitefish: Synthetic MiR92b-3p uptake and the efficacy of gene expression silencing.

The delivery of short snippets of RNA, such as synthetic miRNA agents, is an essential step for achieving RNA-mediated knockdown, which has not been studied in sufficient detail in fish. Our results indicate that a MiR92b-3p mimic may be effectively delivered via intraperitoneal injection to the spleen and the liver of whitefish, and that it likely achieves functionality without causing any apparent toxic effects in the challenged animals. We report the novel finding that the MiR92b-3p mimic reduced the in vivo liver mRNA expression levels of its putative pro-apoptotic targets (p53, cdkn1a, and pcna), and important metabolic genes, e.g. cdo1. This shows that this methodology of MiR92b-3p mimic transfection in vivo may be a useful tool for studies that investigate the molecular pathways that confer pro-proliferative and anti-apoptotic phenotypes or those that regulate intracellular metabolism in fish and other vertebrates.

Source apportionment and health risk assessment of ambient volatile organic compounds in primary schools in Northern Taiwan

This study conducted a source apportionment and health risk estimation of ambient volatile organic compounds in Taoyuan and Zhongli (Taiwan) primary schools. In particular, principal component analysis followed by absolute principal component scores was used in order to identify and quantify the emission sources of volatile organic compounds. Health risk was determined on the basis of age group and gender using the method recommended by the United States Environmental Protection Agency, and Monte Carlo simulation was applied to analyze uncertainty and sensitivity. Results revealed that solvent usage in household product industries (56%) had the highest contribution of volatile organic compounds in Taoyuan and was followed by solvent usage in electronics manufacturing (27%) and oil refineries and storage leaks (17%). The main volatile organic compounds sources in Zhongli were vehicle emissions (48%) and liquefied petroleum gas/natural gas leakage (52%). Vehicle emissions and solvent usage in electronics manufacturing and household product industries were revealed as the primary sources of benzene, toluene, ethylbenzene, and xylenes, which were considered the compounds with high health risk for residents. The mean cumulative value of cancer risk ranged from 5.45 × 10−7 to 3.05 × 10−4, and the non-carcinogenic risk index for all age groups and genders was less than 1. The mean cumulative cancer risk was categorized as follows: below the limit recommended by United States Environmental Protection Agency, possible risk, probable risk, and definite risk. The magnitude of risks varied among age groups and between genders, and the variations in risk were statistically insignificant.

The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China

Air concentrations of volatile organic compounds (VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and 9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most (36.15%) to the total propene-equivalent concentration of the measured VOCs, followed by combustion emission (16.92%), vegetation emission and secondary formation (14.33%), solvent usage (10.59%), petrochemical industry emission (9.89%), petrol evaporation (6.28%), and liquefied petroleum gas (LPG) usage (5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics, e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O3 pollution in Shenyang.

English

Teaching is the process of imparting knowledge by teachers in learners. To enhance this, methods of presenting information visually to a full room of students at once are used. This includes writing on whiteboards written using whiteboard marker pens. Dry erase ink for whiteboard marker pen is composed of volatile solvent vehicle which easily vaporizes allowing the mark to dry on the surface of the whiteboard. Different manufactures use different solvents and different composition ratios in their ink brands. Different mixtures of VOCs have different irritation thresholds and potencies. This study sought to establish the components of vapour produced when different dry erase inks used in secondary schools in Nakuru County evaporate and compare their ability to elicit eye irritation on the teachers. The study design was repeated measures. Thirteen secondary schools which used whiteboards only in the classrooms were selected purposefully and the teachers in these schools were randomly selected; there were 224 respondents. Questionnaires were used to collect data on self-reported eye irritations while chromatography was used to identify the components of the vapours produced by the different brands of ink. The three ink brands used in the schools were found to contain acetone, ethanol, hexane and methanol. Inks 2 and 3 were found to have a more potent mixture than ink 1 (Odds ratio= 2.182; 95 C.I. =1.174-4.054). The study concludes that different ink solvent mixtures have different abilities to elicit eye irritation on persons exposed to their vapours (&chi;2 =6.933; p=0.031) and that methanol and acetone solvent mixture (found in ink 1) were the least potent eye irritants. Key words: Dry erase, eye irritation, secondary schools, solvents mixture, teachers. &nbsp; &nbsp

Control Interventions Can Impact Alveolarization and the Transcriptome in Developing Mouse Lungs.

There is currently much interest in understanding the mechanisms of normal and aberrant lung alveolarization, particularly in the context of bronchopulmonary dysplasia, a common complication of preterm birth where alveolarization is impeded. To this end, the parenteral administration of pharmacological agents that modulate biochemical pathways, or facilitate modulation of gene expression in transgenic animals, has facilitated the discovery and validation of mechanisms that direct lung development. Such studies include control interventions, where the solvent vehicle, perhaps containing an inactive form of the agent applied, is administered; thereby providing a well-controlled point of reference for the analysis of the partner experiment. In the present study, the impact of several widely used control interventions in developing C57Bl/6J mouse pups was examined for effects on lung structure and the lung transcriptome. Parenteral administration of scrambled microRNA inhibitors (called antagomiRs) that are used to control in vivo microRNA neutralization studies, impacted lung volume, septal thickness, and the transcriptome of developing mouse lungs; with some effects dependent upon nucleotide sequence. Repeated intraperitoneal isotonic saline injections altered lung volume, with limited impact on the transcriptome. Parenteral administration of the tamoxifen solvent Miglyol accelerated mouse pup growth, and changed the abundance of 73 mRNA transcripts in the lung. Tamoxifen applied in Miglyol-in the absence of Cre recombinase-decreased pup growth, lung volume, and lung alveolarization and changed the abundance of 298 mRNA transcripts in the lung. These data demonstrate that widely used control interventions can directly impact lung alveolarization and the lung transcriptome in studies on lung development. Anat Rec, 302:346-363, 2019. © 2018 Wiley Periodicals, Inc.

Abstract 16718: Electronic Cigarette Aerosols Alter Cardiac Expression of Genes Key to Electrical and Structural Remodeling in Mice

Background: Electronic cigarette (e-cig) use has mounted. Some health authorities have even proclaimed e-cigs are profoundly safer than conventional cigarettes. However, e-cigs generate several potentially cardiotoxic constituents by heating their solvent vehicles propylene glycol (PG) and vegetable glycerin (VG) into aerosols to deliver nicotine and flavors. Objectives: To investigate the effects of chronic E-cig exposures, with or without nicotine, on cardiac gene expression compared to mainstream cigarette smoke (MCS). Methods: Healthy C57BL/6J male mice were exposed chronically (12 weeks, 3 hours/day) to e-cig aerosols from an equal-ratio mixture of PG and VG (PG:VG) with nicotine (36 mg/mL) or without nicotine, or to MCS, and compared to filtered air control group (Air). Hearts (n=8/group) were assayed by quantitative PCR for expression of genes associated with electrical and structural remodeling. Results: PG:VG exposure increased gene expression for a gap junction protein (connexin 43, 1.8-fold), voltage-gated potassium and sodium channels (K v 4.3, 2.5-fold; Na v 1.5, 1.6-fold), calcium sequestration protein (sarco/endoplasmic reticulum calcium ATP-ase, 1.4-fold), cytokines (TGFβ1, 1.8-fold; TNF-α, 3.8-fold), and collagen III (3.8-fold) relative to Air (all P &lt; 0.05). Nicotine did not enhance PG:VG’s effects on gene expression relative to PG:VG-alone (all P &gt; 0.05), and cigarette smoke did not significantly affect any of the transcripts assayed (all P &gt; 0.05 vs. Air). Conclusions: E-cigs may induce cardiac electrical and structural remodeling via their primary vehicle ingredients and irrespective of nicotine or flavors. Such effects could precipitate fatal arrhythmia, stroke, and/or heart failure. Electronic nicotine delivery systems may pose cardiac risks distinct from conventional cigarettes.

Toxicity and Mutagenicity Evaluation Following RISUG Contraception Reversal in Rats.

Reestablishment of fertility, after a male contraceptive method, is of great concern. In this context, RISUG (Reversible Inhibition of Sperm Under Guidance) has been evaluated for its mutagenicity following reversibility with dimethyl sulfoxide (DMSO)/sodium bicarbonate (NaHCO3) in Wistar albino rats. Animals were divided into 7 groups, namely, sham-operated control, vas occlusion with RISUG for 90 and 360 days, reversal with DMSO and NaHCO3 after 90 and 360 days, respectively. The testis, cauda epididymis, cauda epididymal spermatozoa, and serum were evaluated for apoptosis and hormonal status through various assays. RISUG was subjected to Ames test at dose levels of 10, 50, and 100 µL. Results of terminal deoxynucleotidyl transferase nick end labeling and caspase-3 assays in testes and cauda epididymis revealed that the percentage of positive cells in the experimental groups was comparable to sham-operated control. Annexin V assay in cauda epididymal spermatozoa showed slight elevation in group II ( P < 0.05), whereas in the remaining groups, minimum numbers of positive sperms were found. Hormone profile, namely, testosterone, prolactin, cortisol, prostate-specific antigen, and sperm antibody concentration, remained unchanged. In Ames test, no significant increase was observed in the number of revertant colonies on plates containing RISUG in the presence and absence of S9 mix in all 3 strains. Therefore, the reversal of RISUG-induced contraception by solvent vehicle DMSO/NaHCO3 was successful without any toxicity at the cellular levels.

Comparative study of volatile organic compounds in ambient air using observed mixing ratios and initial mixing ratios taking chemical loss into account – A case study in a typical urban area in Beijing

Volatile organic compounds (VOCs) can react with atmospheric radicals while being transported after being emitted, resulting in substantial losses. Using only observed VOC mixing ratios to assess VOC pollution, is therefore problematic. The observed mixing ratios and initial mixing ratios taking chemical loss into consideration were performed using data for 90 VOCs in the atmosphere in a typical urban area in Beijing in winter 2013 to gain a more accurate view of VOC pollution. The VOC sources, ambient VOC mixing ratios and compositions, variability and influencing factors, contributions to near-ground-ozone and health risks posed were assessed. Source apportionment should be conducted using initial mixing ratios, but health risks should be assessed using observed mixing ratios. The daytime daily mean initial mixing ratio (72.62ppbv) was 7.72ppbv higher than the daytime daily mean observed mixing ratio (64.90ppbv). Alkenes contributed >70% of the consumed VOCs. The nighttime daily mean observed mixing ratio was 71.66ppbv, 6.76ppbv higher than the daytime mixing ratio. The observed mixing ratio for 66 VOCs was 40.31% higher in Beijing than New York. The OFPs of Ini-D (266.54ppbv) was underestimated 23.41% compared to the OFP of Obs-D (204.14ppbv), improving emission control of ethylene and propene would be an effective way of controlling O3. Health risk assessments performed for 28 hazardous VOCs show that benzene, chloroform, 1,2-dichloroethane, and acetaldehyde pose carcinogenic risk and acrolein poses non-carcinogenic risks. Source apportionment results indicated that vehicle exhausts, solvent usage and industrial processes were the main VOC source during the study.