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Amines play an important role in the formation and transformation of atmospheric aerosols. Gaseous phase and PM2.5 samples were collected simultaneously at Nanling Mountains, southern China during autumn 2016 and summer 2017. The site is strongly affected by long distance transport from marine and continental air masses. Five amines, methylamine (MA), dimethylamine (DMA), diethylamine (DEA), dibutylamine (DBA) and morpholine (MOR), were detected by gas chromatography-mass spectrometry (GC-MS) after derivatization. The backward trajectory analyses suggested that different origins of air masses led to seasonal variation of amines. In gaseous phase samples, the average concentrations of total measured amines (Ʃamines) were 193.4 ± 111.7 ng m−3 in autumn 2016 and 307.5 ± 196.7 ng m−3 in summer 2017. In PM2.5 samples, the average concentrations of Ʃamines were 12.4 ± 10.8 ng m−3 in autumn 2016 and 20.7 ± 11.0 ng m−3 in summer 2017. MA and DMA were the dominant amines, together contributing approximately 70% to gaseous amines and 80% to particulate amines. A strong linear relationship was found between Ʃamines and NO3− in PM2.5, implying that amines might mainly exist in the form of aminium nitrate. Ammonium (NH4+) was found mostly likely in the form of ammonia sulfate. Approximately 7.4% of the gaseous total amines partitioned to PM2.5. A good linear relationship between the fraction of total atmospheric concentration sorbed by PM2.5 (Φ) and the concentrations of O3 was found, suggesting that O3 likely played an important factor in the gas-to-particle partitioning of amines. Additionally, under high relative humidity circumstances (92% ± 7.0%), direct dissolution was a crucial step for gaseous amines partitioning into particles. The ratios of amines-C to water-soluble organic carbon (WSOC) and amines-N to water-soluble organic nitrogen (WSON) were 0.21% and 1.57% in autumn 2016 and 0.54% and 2.08% in summer 2017, respectively. The results of this study provide essential information on the formation mechanism of particulate amines.

The formation of secondary organic aerosol (SOA) from isoprene ozonolysis was investigated using a FEP Teflon reactor with and without the presence of H2O, CO, SO2 and UV-light irradiation (365 nm) to reveal their possible influence on SOA formation. Compared with the base experiment (isoprene + O3) under dark condition, the presence of 2000 ppm H2O and 1000 ppm CO could remarkably suppress SOA formation from isoprene ozonolysis, with SOA yields reduced from 2.96% to 1.47% and 2.08%, respectively. The evident reduction of SOA yields from isoprene ozonolysis with the presence of H2O and CO was mainly ascribed to the suppression of Stable Criegee Intermediates (SCIs). In contrast, the particle yield from isoprene ozonolysis with the presence of SO2 pronouncedly increased from 2.96% to 57.9%, suggesting that the oxidation of SO2 by SCIs made great contribution to the particle formation. The SOA or particle yields from all the reaction systems with and without presence of H2O, CO and SO2 reduced more than 27% under the UV-light irradiation with respect to dark condition, which were mainly attributed to the SCIs photolysis. The contribution of OH channel to SOA formation from isoprene ozonolysis was estimated to be less than 30%. Considering the 50% reduction of SOA yield from isoprene ozonolysis under light irradiation, the disappearance of the component with low O:C and H:C and high molecule weight in the SOA sample collected under light irradiation indicated the polymerization of unsaturated SCIs might be an important SOA formation channel besides the oligomerization of SCIs, HCHO, and MACR from isoprene ozonolysis under dark condition.

The coexistence of Zn-Pb deposits and oil/gas reservoirs demonstrates that a close genetic link between them. The Nanmushu is a large Mississippi Valley-Type (MVT) Zn-Pb deposit discovered on the northern margin of the Yangtze block in recent years. The deposit is hosted in the Ediacaran Dengying Formation dolostone, accompanied by large amount of bitumen in the orebodies. The MVT Zn-Pb deposit overlaps with the paleo-oil/gas reservoir horizontally, and sandwiched in the paleo-oil/gas reservoirs at depth. The Cambrian Guojiaba Formation may have provided not only the oil for paleo-oil/gas reservoirs, but also ore metals for the Zn-Pb mineralization. With increasing burial depth, the Guojiaba Formation may have become more mature to form metal-rich fluids, and the metals migrated and accumulated with hydrocarbons to form a paleo-oil reservoir. Large-scale Zn-Pb mineralization may have occurred in the destruction process of paleo-gas reservoir. With the deep burial of paleo-oil reservoir, the paleo-oil reservoir may have transformed into a paleo-gas reservoir. Decoupling of metals and hydrocarbons during the paleo-gas reservoir formation may have provided the ore metals. Thermal sulfate reduction (TSR) during the paleo-oil/gas reservoirs formation may have provided the hydrogen sulfide for mineralization. Decompression and cooling during the paleo-gas reservoir destruction may have formed extensive metal sulfide precipitation and mineralization.

Aims Hair cell reduction was related to diabetes-induced hearing loss. Oxidative stress, endoplasmic reticulum stress, and autophagy participate in this process. Thioredoxin (Trx) is a protein with many biological functions which can regulate them. In this study, aiming to clarify protective effect of Trx on diabetic hearing loss and to identify an early potential therapeutic target for diabetic hearing impairment in the future. Methods Trx transgenic (Tg) mice were used to establish a diabetic model by intraperitoneally injecting streptozotocin (STZ) and with/without SF or PX12 treatment. Succinate dehydrogenase (SDH) staining was used to evaluate the loss of hair cells. The relative expression of related proteins and genes was detected using western blotting and qRT-PCR. Results In vivo, loss of outer hair cells was observed. However, it can be delayed Trx overexpression. Moreover, the expression of PGC-1α, bcl-2 and LC3 was increased in Tg(+)-DM mice compared with Tg(-)-DM mice. The expression of ASK1, Txnip, GRP78, CHOP and p62 was decreased in Tg(+)-DM mice compared with Tg(-)-DM mice. Conclusions Upregulation of Trx protects diabetes-induced cochlear hair cells reduction. The underlying mechanisms were related to the regulation of ER stress through ASK1 and the mitochondrial pathway or autophagy via Txnip.

Size-segregated PM 10 samples were collected in Guangzhou, China during autumn of 2014. Nine amines, including seven aliphatic amines and two heterocyclic amines, were detected using a gas chromatography-mass spectrometer after derivatization by benzenesulfonyl chloride. The total concentration of the nine amines (Ʃamines) was 79.6–140.9 ng m −3 in PM 10 . The most abundant species was methylamine (MA), which had a concentration of 29.2–70.1 ng m −3 . MA, dimethylamine (DMA), diethylamine (DEA) and dibutylamine (DBA) were the predominant amines in the samples and accounted for approximately 80% of Ʃamines in each size segment. Two heterocyclic amines, pyrrolidine (PYR) and morpholine (MOR), were detected in all samples and had average concentrations of 1.14 ± 0.37 and 1.89 ± 0.64 ng m −3 , respectively, in particles with aerodynamic diameters 10 were 7.9 ± 1.6 μg m −2 d −1 and 0.084 ± 0.0021 cm s −1 , respectively. The results of this study provide essential information on the contribution of amines to secondary organic aerosols and dry removal mechanisms in urban areas.

Interactions between clouds and black carbon (BC) represent a significant uncertainty in aerosol radiative forcing. To investigate the influence of cloud processing on the scavenging of BC, concurrent measurement of individual cloud droplet residue particles (cloud RES) and interstitial particles (cloud INT) throughout a cloud event was deployed at Mt. Tianjing (1690 m a.s.l.) in southern China. An aethalometer (AE-33), a single particle aerosol mass spectrometer (SPAMS) and a scanning mobility particle sizer (SMPS) were used to investigate the mass concentration of equivalent BC (EBC), size-resolved number of BC-containing particles, and size-resolved number concentration of submicron particles in real-time, respectively. The number-based SEs of the submicron particles varied between 2.7 and 31.1%. Mass scavenging efficiency (MSE) ranged from 4.7% to 52.6% for EBC, consistent with the number-based SE (from 11.3% to 59.6%) of the BC-containing particles throughout the cloud event. Several factors that may influence the SEs of the BC-containing particles are considered and examined. SEs are most likely determined by a single factor, i.e., liquid water content (LWC), with R2 > 0.8 in a power function throughout the cloud event. Stage-resolved investigation of SEs further reveals that particle size matters more than other factors in the cloud formation stage, whereas there is an increasing role of the mixing state in the development and stability stage. We also observed lower SEs for the BC-containing particles internally mixed organics, consistent with previous literature.

Amines are ubiquitous in the environment and pose potential impacts on atmospheric chemistry; however, their seasonal variations and atmospheric processes remain unclear. In this study, a single-particle aerosol mass spectrometer is employed to investigate the seasonal variations of amine-containing particles as well as the oxidation of trimethylamine (TMA) in the urban region of Guangzhou, China. Number fractions of the amine-containing particles exhibit distinct seasonal variations, with higher fractions in spring and summer. Four amines, namely, TMA, diethylamine (DEA), dipropylamine, and tripropylamine are observed over all the seasons. DEA and TMA are the most dominant and account for approximately 90% of all these amine-containing particles. They are mainly clustered into eight types, comprised of internally mixed organics and elemental carbon (OCEC), OC–K, EC, Metal–rich, Dust, NaK–EC, Amine–rich, and high molecular weight organic compounds. DEA and TMA distribute differently over particle types and exhibit a distinct mixing state because of their different physicochemical properties. Compared with TMA, DEA is associated with more sulfate. The possible oxidation of TMA is also investigated, and the results indicate the potential contribution of aqueous oxidation or NO3 radical oxidation to the formation of TMA oxide. Overall, the results improve the comprehension of the formation and evolution processes of amines in atmospheric environment.