Aqueous production of secondary organic aerosol from fossil-fuel emissions in winter Beijing haze.

Secondary organic aerosol (SOA) produced by atmospheric oxidation of primary emitted precursors is a major contributor to fine particulate matter (PM2.5) air pollution worldwide. Observations during winter haze pollution episodes in urban China show that most of this SOA originates from fossil-fuel combustion but the chemical mechanisms involved are unclear. Here we report field observations in a Beijing winter haze event that reveal fast aqueous-phase conversion of fossil-fuel primary organic aerosol (POA) to SOA at high relative humidity. Analyses of aerosol mass spectra and elemental ratios indicate that ring-breaking oxidation of POA aromatic species, leading to functionalization as carbonyls and carboxylic acids, may serve as the dominant mechanism for this SOA formation. A POA origin for SOA could explain why SOA has been decreasing over the 2013-2018 period in response to POA emission controls even as emissions of volatile organic compounds (VOCs) have remained flat.

Emission and optical characteristics of brown carbon in size-segregated particles from three types of Chinese ships.

Brown carbon (BrC) is one of the important light absorption substances that have high light absorption ability under short wavelength light. However, limit studies have focused on the BrC emission from ships. In this study, size-segregated particulate matters (PM) were collected from three different types of ships, light absorption characteristics and size distribution of methanol-soluble BrC and water-soluble BrC in PM from ship exhausts were investigated. Results showed that four-stroke low-power diesel fishing boat (4-LDF) had the highest mass concentrations of methanol-soluble organic carbon (MSOC) and water-soluble organic carbon (WSOC), followed by 2-stroke high-power heavy-fuel-oil vessel (2-HHV), and four-stroke high-power marine-diesel vessel (4-HMV). While 2-HHV had obviously higher light absorption coefficients of methanol-soluble BrC (Abs365,M) and water-soluble BrC (Abs365,W) in unit weight of PM than the other two types of ships. The tested ships presented comparable or higher absorption efficiency of BrC in water extracts (MAE365,W) compared with other BrC emission sources. Majority of BrC was concentrated in fine particles, and the particle size distributions of both Abs365,M and Abs365,W showed bimodal patterns, peaking at 0.43-0.65 µm and 4.7-5.8 µm, respectively. However, different particle size distributions were found for MAE365,M between diesel and heavy fuel oil ships. Besides, different wavelength dependence in particles with different size were also detected. Ship exhaust could be confirmed as a non-ignorable BrC emission source, and complex influencing factor could affect the light absorption characteristics of ship emissions. Particle size should also be considered when light absorption ability of BrC was evaluated.

Adenosquamous carcinoma of the liver: The challenge of diagnosis.

Adenosquamous carcinoma of the liver is extremely rare. We report a case of adenosquamous carcinoma in the intrahepatic bile duct of a 56-year-old woman who complained of persistent abdominal pain, shivering and hyperthermia. Computed tomography demonstrated a solid-cystic neoplasm in segment 5/6/8 of the liver with a gradual enhancement pattern in the solid area. However, postoperative pathological examination showed adenosquamous carcinoma of intrahepatic bile duct.

Secondary Formation of Atmospheric Brown Carbon in China Haze: Implication for an Enhancing Role of Ammonia.

Optical characteristics and molecular compositions of brown carbon (BrC) were investigated during winter 2019 at a rural site of China with a focus on nitro-aromatic compounds (NACs) and imidazoles (IMs). The abundance of gaseous nitrophenols relative to CO during the campaign maximized at noontime, being similar to O3, while the particulate NACs during the haze periods strongly correlated with toluene and NO2, suggesting that NACs in the region are largely formed from the gas-phase photooxidation. Strong correlations of particulate IMs in the dry haze periods with the mass ratio of EC/PM2.5 and the concentration of levoglucosan were observed, indicating that IMs during the dry events are largely derived from biomass burning emissions. However, an increase in IMs with the increasing aerosol liquid water content and pH was observed in the humid haze events, along with much lower abundances of levoglucosan and K+ relative to PM2.5, suggesting that IMs were mostly formed from aqueous reactions in the humid haze periods. These IMs exponentially increased with an increasing NH3 owing to an aqueous reaction of carbonyls with free ammonia. Our findings for the first time revealed an enhancing effect of ammonia on BrC formation in China, especially in humid haze periods.

Significant coal combustion contribution to water-soluble brown carbon during winter in Xingtai, China: Optical properties and sources.

To understand the characteristics of atmospheric brown carbon (BrC), daily PM2.5 samples in Xingtai, a small city in North China Plain (NCP), during the four seasons of 2018-2019, were collected and analyzed for optical properties and chemical compositions. The light absorption at 365 nm (absλ=365 nm) displayed a strong seasonal variation with the highest value in winter (29.0±14.3 M/m), which was 3.2∼5.4-fold of that in other seasons. A strong correlation of absλ=365 nm with benzo(b)fluoranthene (BbF) was only observed in winter, indicating that coal combustion was the major source for BrC in the season due to the enhanced domestic heating. The mass absorbing efficiency of BrC also exhibited a similar seasonal pattern, and was found to correlate linearly with the aerosol pH, suggesting a positive effect of aerosol acidity on the optical properties and formation of BrC in the city. Positive matrix factorization (PMF) analysis further showed that on a yearly basis the major source for BrC was biomass burning, which accounted for 34% of the total BrC, followed by secondary formation (26.7%), coal combustion (21.3%) and fugitive dust (18%). However, the contribution from coal combustion was remarkably enhanced in winter, accounting for ∼40% of the total. Our work revealed that more efforts of "shifting coal to clean energy" are necessary in rural areas and small cities in NCP in order to further mitigate PM2.5 pollution in China.

miR-1285 Restrains Gastric Cancer Cell Growth and Causes Apoptosis by Negatively Regulating RAB1A.

MicroRNAs (miRNAs) act as critical biological factors in gastric cancer (GC). miR-1285 has been ascertained as a crucial antioncogene in some cancers. However, the effect of miR-1285 in GC and the regulatory mechanism are not clear. In this study, we revealed that miR-1285 expression was significantly reduced in GC. Overexpressing miR-1285 restrained GC cell multiplication and accelerated apoptosis, whereas suppressing miR-1285 facilitated cell growth and restrained apoptosis. The level of miR-1285 was negatively related to the RAB1A level in GC tissue specimens. RAB1A was verified by reporter gene assay as a target of miR-1285. Overexpression of miR-1285 suppressed the RAB1A level, whereas suppression of miR-1285 promoted the level of RAB1A expression. Knockdown of RAB1A resulted in analogical biological effect as that caused by overexpressing miR-1285. Moreover, both miR-1285 overexpression and RAB1A knockdown led to suppression of the mTOR/S6K1 pathway. By contrast, inhibition of miR-1285 promoted the mTOR/S6K1 pathway. In addition, miR-1285 also regulated the Bcl-2/Bax pathway. Taken together, our data indicate that miR-1285 suppresses GC cell multiplication by restraining the mTOR/S6K1 pathway and induces cell apoptosis by regulating the Bcl-2/Bax pathway via modulating RAB1A.

Characteristics and health risks of parent, alkylated, and oxygenated PAHs and their contributions to reactive oxygen species from PM2.5 vehicular emissions in the longest tunnel in downtown Xi'an, China.

A vehicular emission study was conducted in the longest inner-city tunnel in Xi'an, northwestern China in four time periods (I: 07:30-10:30, II: 11:00-14:00, III: 16:30-19:30, and IV: 20:00-23:00 LST). A sum of 40 PAHs, including parent (p-PAHs), alkylated (a-PAHs), and oxygenated (o-PAHs) in fine particulate matter (PM2.5) were quantified. The relationships between the PAHs and the formation of reactive oxygen species (ROS) were also studied. The average total quantified PAHs concentration was 236.3 ± 48.3 ng m-3. The p-PAHs were found to be the most dominated group, accounting for an average of 88.1% of the total quantified PAHs, followed by a-PAHs (6.1%) and o-PAHs (5.8%). On the base of the number of aromatic rings, the groups of ≤5 rings (92.5 ± 1.2%) had higher fractions than the high ones (≥6 rings, 7.5 ± 1.2%) for pPAHs. Diurnal variations of PAHs subgroups exhibited the highest levels in Period III, consistent with the largest traffic counts in evening rush hours. However, less reduction of few PAHs in the night period demonstrates that the emissions of compressed natural gas (CNG) and methanol-fueled vehicles cannot be ignored while their contribution increased. High ROS activity levels were observed in the traffic-dominated samples, implying the potential oxidative damages to humans. Additionally, diurnal variation of the ROS activity was consistent with the total quantified PAHs and toxic equivalency of benzo[a]pyrene. Good correlations (R > 0.6, p < 0.05) were seen between individual groups of PAHs (especially for 3-5 rings p-PAHs, 4 rings a-PAHs, and 2-3 rings o-PAHs) and ROS activity, supporting that the vehicular emitted PAHs possibly initiate oxidative stress. The multiple linear regression analysis further illustrated that chrysene contributed the highest (25.0%) to ROS activity. In addition to highlighting the potential hazards to the PAHs from the vehicular emission, their roles to mitigate the health effects by formations of ROS were firstly reported in northwestern China.

Characteristics, formation, and sources of PM2.5 in 2020 in Suzhou, Yangtze River Delta, China.

Here we present seasonal chemical characteristics, formations, sources of PM2.5 in the year 2020 in Suzhou, Yangtze River Delta, China. Expectedly, organic matter (OM) found to be the most dominant component of PM2.5, with a year-average value of 10.3 ± 5.5 µg m-3, followed by NO3- (6.7 ± 6.5 µg m-3), SO42- (3.3 ± 2.5 µg m-3), NH4+ (3.2 ± 2.8 µg m-3), EC (1.1 ± 1.3 µg m-3), Cl- (0.57 ± 0.56 µg m-3), Ca2+ (0.55 ± 0.91 µg m-3), K+ (0.2 ± 1.0 µg m-3), Na+ (0.18 ± 0.45 µg m-3), and Mg2+ (0.09 ± 0.15 µg m-3). Seasonal variations of PM2.5 showed the highest average value in spring, followed by winter, fall, and summer. Meanwhile, the formation mechanisms of the major PM2.5 species (NO3-, SO42-, and OM) varied in seasons. Interestingly, NO2 may have the highest conversion rate to NO3- in spring, which might be linked with the nighttime chemistry due to the high relative humidity. Moreover, OM in summer was mainly produced by the daytime oxidation of volatile organic compounds, while local primary organic aerosols might play a significant role in other seasons. Source apportionment showed that the more-aged PM2.5 contributed significantly to the PM2.5 mass (42%), followed by the dust-related PM2.5 (38%) and the less-aged PM2.5 (21%). Potential contribution source function (PSCF) results indicated that aged PM2.5 were less affected by transportation than dust-related PM2.5.

Evaluating Left Ventricular Systolic Synchronicity with Real-Time 3D Echocardiography in Newborns.

Knowing the normal values of left ventricular (LV) systolic synchronicity in the early neonatal period is very important for understanding myocardial function. This retrospective study analyzed data of 105 newborns who were examined using real-time 3-dimensional echocardiography (RT3DE). The time to the point of minimal regional systolic volume (Tmsv) was measured from volume-time curves in each segment. Standard deviation (SD) and maximal difference (Dif) of Tmsv were calculated from 16 (6 basal/6 mid/4 apical), 12 (6 basal/6 mid), and 6 (basal) LV segments with the corresponding parameters adjusted for the R-R interval. Influences of age, sex, gestational age, birth weight, and heart rate on parameters were explored. Data showed no significant difference among Tmsv-16-SD, Tmsv-12-SD, and Tmsv-6-SD. A strong correlation was found between Tmsv-6-SD and Tmsv-6-Dif (r = 0.83, P < 0.001), Tmsv-12-SD and Tmsv-6-SD (r = 0.77, P < 0.001), and Tmsv-12-Dif and Tmsv-6-Dif (r = 0.76, P < 0.001) and a moderate correlation was found between Tmsv-16-SD and Tmsv-16-Dif (r = 0.66, P < 0.001), Tmsv-6-SD and Tmsv-12-Dif (r = 0.62, P < 0.001), and Tmsv-12-SD and Tmsv-6-Dif (r = 0.61, P < 0.001). Heart rate correlated negatively with Tmsv (r = - 0.03 to - 0.11, P < 0.004-0.000), but had no effect on parameters adjusted for %R-R. Age, sex, gestational age, and birth weight did not affect any of these parameters. Tmsv-Dif and Tmsv-SD measured from 16 segments using RT3DE are useful as possible parameters for evaluating LV systolic synchronicity in normal newborns.

First Report of Nondeletional Hb H Disease Caused by an α2-Globin Gene Mutation: HBA2: c.184A>T.

We report a rare mutation, HBA2: c.184A>T on the α2-globin gene, detected in a Chinese proband who presented with Hb H disease and a mild anemia. This frameshift mutation results in a premature termination of translation at position 61 of the α2-globin gene. Carriers of this mutation showed a borderline microcytic hypochromia. Our study indicates the importance of screening nondeletional α-thalassemia (α-thal) in areas with a particularly high prevalence of thalassemia such as in Southern China, especially for couples with one partner carrying an α0-thal deletion.

A New Hemoglobin Variant: Hb Jiujiang [α18(A16)Gly→Cys, HBA2: c.55G>T].

We have identified a new α chain hemoglobin (Hb) variant in a Chinese subject. Sequencing of the α-globin gene revealed a mutation in exon 1 at nucleotide 55, which results in the replacement of a glycine by cysteine at codon 18 [α18(A16)Gly→Cys, HBA2: c.55G>T] that we have named Hb Jiujiang for the region of origin of the proband.

Comparison of air pollutants and their health effects in two developed regions in China during the COVID-19 pandemic.

Air pollution attributed to substantial anthropogenic emissions and significant secondary formation processes have been reported frequently in China, especially in Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD). In order to investigate the aerosol evolution processes before, in, and after the novel coronavirus (COVID-19) lockdown period of 2020, ambient monitoring data of six air pollutants were analyzed from Jan 1 to Apr 11 in both 2020 and 2019. Our results showed that the six ambient pollutants concentrations were much lower during the COVID-19 lockdown due to a great reduction of anthropogenic emissions. BTH suffered from air pollution more seriously in comparison of YRD, suggesting the differences in the industrial structures of these two regions. The significant difference between the normalized ratios of CO and NO2 during COVID-19 lockdown, along with the increasing PM2.5, indicated the oxidation of NO2 to form nitrate and the dominant contribution of secondary processes on PM2.5. In addition, the most health risk factor was PM2.5 and health-risked based air quality index (HAQI) values during the COVID-19 pandemic in YRD in 2020 were all lower than those in 2019. Our findings suggest that the reduction of anthropogenic emissions is essential to mitigate PM2.5 pollution, while O3 control may be more complicated.

Chronic real-time particulate matter exposure causes rat pulmonary arteriole hyperresponsiveness and remodeling: The role of ETBR-ERK1/2 signaling.

Exposure to air pollution is associated with the incidence of respiratory diseases. The present study evaluated the pulmonary vascular system injury by chronic real-time particulate matter (PM10) exposure and investigated the underlying mechanisms. Rats were exposed to PM10 or filtered air for 2 to 4 months using a whole body exposure system, and intraperitoneally injected with the MEK1/2 inhibitor U0126. Right heart catheterization and myography were performed to detect lung function and pulmonary vascular reactivity, respectively. Western blotting, qRT-PCR, enzyme-linked immunosorbent assay and histological analyses were used to detect the effects and mechanisms by which PM10 exposure-induced pulmonary vascular dysfunction. Functional experiment results showed that PM10 exposure increased the pulmonary artery pressure of rats and caused endothelin B receptor (ETBR)-mediated pulmonary arteriole hyperreactivity. U0126 significantly rescued these pathological changes. PM10 exposure upregulated the contractile ETBR of pulmonary arteriolar smooth muscle, and damaged pulmonary artery endothelial cells to induce the release of more endothelin 1 (ET-1). The upregulated ETBR bound to increased ET-1 induced pulmonary arteriolar hyperresponsiveness and remodeling. U0126 inhibited the PM10 exposure-induced upregulation of ETBR in pulmonary arteriole, ETBR-mediated pulmonary arterial hyperresponsiveness and vascular remodeling. In conclusion, chronic real-time particulate matter exposure can activate the ERK1/2 signaling, thereby inducing the upregulation of contractile ETBR in pulmonary arteriole, which may be involved in pulmonary arteriole hyperresponsiveness and remodeling in rats. These findings provide new mechanistic evidence of PM10 exposure-induced respiratory diseases, and a new possible target for treatment.

Synergistic Uptake by Acidic Sulfate Particles of Gaseous Mixtures of Glyoxal and Pinanediol.

The uptake of gaseous organic species by atmospheric particles can be affected by the reactive interactions among multiple co-condensing species, yet the underlying mechanisms remain poorly understand. Here, the uptake of unary and binary mixtures of glyoxal and pinanediol by neutral and acidic sulfate particles is investigated. These species are important products from the oxidation of volatile organic compounds (VOCs) under atmospheric conditions. The uptake to acidic aerosol particles greatly increased for a binary mixture of glyoxal and pinanediol compared to the unary counterparts. The strength of the synergism depended on the particle acidity and water content (i.e., relative humidity). The greater uptake was up to 2.5× to 8× at 10% relative humidity (RH) for glyoxal and pinanediol, respectively. At 50% RH, it was 2× and 1.2× for the two species. Possible mechanisms of acid-catalyzed cross reactions between the species are proposed to explain the synergistic uptake. The proposed mechanisms are applicable to a broader extent across atmospheric species having carbonyl and hydroxyl functionalities. The results thus suggest that synergistic uptake reactions can be expected to significantly influence the gas-particle partitioning of VOC oxidation products under atmospheric conditions and thus greatly affect their atmospheric transport and lifetime.

Investigation of Primary and Secondary Particulate Brown Carbon in Two Chinese Cities of Xi'an and Hong Kong in Wintertime.

Brown carbon (BrC), an aerosol carbonaceous matter component, impacts atmospheric radiation and global climate because of its absorption in the near-ultraviolet-visible region. Simultaneous air sampling was conducted in two megacities of Xi'an (northern) and Hong Kong (southern) in China in winter of 2016-2017. The aim of this study is to determine and characterize the BrC compounds in collected filter samples. Characteristic absorption peaks corresponding to aromatic C-C stretching bands, organo-nitrates, and C═O functional groups were seen in spectra of Xi'an samples, suggesting that the BrC was derived from freshly smoldering biomass and coal combustion as well as aqueous formation of anthropogenic secondary organic carbon. In Hong Kong, the light absorption of secondary BrC accounted for 76% of the total absorbances of BrC. The high abundance of strong C═O groups, biogenic volatile organic compounds (BVOCs) and atmospheric oxidants suggest secondary BrC was likely formed from photochemical oxidation of BVOCs in Hong Kong. Several representative BrC molecular markers were detected using Fourier transform ion cyclotron resonance mass spectrometry and their absorption properties were simulated by quantum chemistry. The results demonstrate that light absorption capacities of secondary anthropogenic BrC with nitro-functional groups were stronger than those of biogenic secondary BrC and anthropogenic primary BrC.

Molecular and Hematological Characterization of a Novel Translation Initiation Codon Mutation of the α2-Globin Gene (ATG>ATC or HBA2: c.3G>C).

Although mutations causing α-thalassemia (α-thal) are mainly larger deletions involving one or both of the duplicated α-globin genes, point mutations are not rare. We have identified a novel mutation of the translation initiation codon of the α2-globin gene with DNA sequencing and allele-specific multiplex ligation-dependent probe amplification (MLPA) in a Chinese family. RNA analysis was performed with reverse transcription-MLPA (RT-MLPA). A novel mutation at the translation initiation codon of the α2-globin gene (HBA2: c.3G>C) was identified. The proband and his father, who were both carriers of this mutation, had a hematological phenotype of mild α+-thalassemia (α+-thal) trait with low-normal limit of mean corpuscular volume (MCV) and normal Hb A2. RNA analysis showed markedly decreased levels of α-globin mRNA and the presence of a small amount of mutant mRNA. The HBA2: c.3G>C mutation most likely caused α-thal by lowering levels of wild α-globin chain. Our study increases the mutation spectrum of α-thal.

Evaluation on exposures to particulate matter at a junior secondary school: a comprehensive study on health risks and effective inflammatory responses in Northwestern China.

Air pollutant measurement and respiratory inflammatory tests were conducted at a junior secondary school in Xi'an, Northwestern China. Hazardous substances including particulate matters (PMs), black carbon (BC) and particle-bounded polycyclic aromatic hydrocarbons (PAHs) were quantified both indoors and outdoors of the school. Source characterization with organic tracers and particle-size distribution demonstrated that the school's air was mostly polluted by combustion emissions from the surrounding environment. The evaluation of health assessment related to air quality was conducted by two methods, including potential risk estimation of air pollutants and direct respiratory inflammatory test. The incremental lifetime cancer risks associated with PAHs were estimated and were 1.62 × 10-6 and 2.34 × 10-6, respectively, for indoor and outdoor fine PMs. Both the values exceeded the threshold value of 1 × 10-6, demonstrating that the carcinogenic PAHs are a health threat to the students. Respiratory inflammatory responses of 50 students who studied in the sample classroom were examined with a fractional exhaled nitric oxide (FeNO) test, with the aid of health questionnaires. The average FeNO concentration was 17.4 ± 8.5 ppb, which was slightly lower than the recommended level of 20 ppb established by the American Thoracic Society for children. However, a wide distribution and 6% of the values were > 35 ppb, suggesting that the potentials were still high for eosinophilic inflammation and responsiveness to corticosteroids. A preliminary interpretation of the relationship between air toxins and respiratory inflammatory response demonstrated the high exposure cancer risks and inflammatory responses of the students to PMs in the city.

Research on the inhibiting effect of tanshinone IIA on colon cancer cell growth via COX-2-Wnt/ß-catenin signaling pathway.

PURPOSE: To investigate the effects of tanshinone IIA (TSIIA) on the colon cancer cell growth and to explore the mechanism of TSIIA in regulating the colon cancer cell growth via cyclooxygenase (COX)-2-Wnt/ß-catenin signaling pathway. METHODS: Colon cancer cell line HC8693 was exposed to different concentrations of TSIIA. After 24-hr exposure, MTT assay was used to detect the lethal concentration of TSIIA on HC8693 cells. The expression levels of COX-2 and ß-catenin were detected by semi-quantitative PCR (sq-PCR). The protein expression levels of COX-2 and ß-catenin were detected by Western blot, and the expression of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay (ELISA). Celecoxib, a COX-2 selective inhibitor, was used to inhibit the COX-2 of HC8693 cells, and the inhibiting effect of TSIIA on HC8693 cell growth was assessed. RESULTS: MTT assay showed that TSIIA concentration of 20µM inhibited significantly the HC8693 cell growth (p<0.01). With reverse transcription after RNA extraction and (sq-PCR) detection the expression levels of COX-2 and ß-catenin were significantly decreased (p<0.01). Western blot showed that the protein expression levels of COX-2 and ß-catenin were significantly decreased (p<0.01). ELISA showed that the expression of VEGF was also significantly decreased (p<0.01); after celecoxib (10µM) was added, 20µM TSIIA had no inhibiting effect on the growth of HC8693 cells (p>0.05). Western blot showed no significant differences in the protein expression levels of COX-2 and ß-catenin compared with those in the control group (not exposed to TSIIA). CONCLUSIONS: TSIIA can inhibit the expression of COX-2 and activate the Wnt/ß-catenin signaling pathway, thus downregulating the level of VEGF, and resulting in growth inhibition of colon cancer cells.

Sample Processing Effect on BK Virus Detection by Real-Time PCR in Urine Samples.

BACKGROUND: Measurement of BK viral DNA in urine by quantitative real-time PCR is a useful tool in monitoring BK viruria and nephropathy. We conducted this study to evaluate the differences in BK virus detection by different sample processing. METHODS: A total of 140 samples from 60 patients were processed by different methods including DNA extraction by spin column from whole urine, urine sediment, and urine supernatant. Boiled urine sediment lysate and untreated urine were also used in this study. RESULTS: The positive rate of BK virus was 34% for whole urine while other methods ranged from 21% - 27%. The quantification data showed that the maximum difference between whole urine and other methods varies from 2.36 - 2.47 log copies/mL in detection of BK virus load, while other methods showed minor differences. CONCLUSIONS: Our results highlight that centrifugation may cause BKV DNA to be lost in urine samples and whole urine is preferred for BK virus monitoring.