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The diverse components, sources, and concentration levels of pollutants in the atmosphere pose significant challenges to understanding the complex formation processes of atmospheric haze. With the advent of environmental mass spectrometry, researchers have been able to gain deeper insights into the composition and further expound the formation mechanisms of atmospheric haze. This review provides a concise overview of mass spectrometers, covering their evolution, components, principles, and applications, particularly in environmental mass spectrometry for the study of atmospheric haze chemistry. The advancements made in understanding atmospheric heterogeneous reactions, volatile organic compound (VOC) oxidation mechanisms and aerosol sources as well as their impact on air quality, using various techniques such as gas chromatography-mass spectrometry (GC-MS), proton-transfer reaction mass spectrometry (PTR-MS), chemical ionization mass spectrometry (CIMS) equipped with different reagent ions, and aerosol mass spectrometer (AMS), are reviewed in detail. The review also suggests future directions for the development of environmental mass spectrometry. • Environmental mass spectrometry offers deeper insights into atmospheric haze chemistry. • Their applications in atmospheric heterogeneous reactions, VOC oxidation and aerosol sources are reviewed. • These advancements mainly involve GC-MS, PTR-MS, CIMS equipped with different reagent ions and AMS. • Future directions are proposed for the development of environmental mass spectrometry. [ABSTRACT FROM AUTHOR]

Amines are frequently detected in atmospheric particles and are internally mixed with other particle-phase components. However, research on the further reactions of amine with reactive species after entering the particle phase is still limited. This study investigated the nitration reaction process of particulate dimethylamine (DMA), formed via a substitution reaction between DMA and (NH 4) 2 SO 4 , with NO x. In situ attenuated total reflectance-infrared Fourier transform spectroscopy (in situ ATR-FTIR) and proton transfer reaction mass spectroscopy (PTR-MS), as well as DFT methods at the B3LYP level using the 6–311++G (d, p) basis set, were mainly used to confirm the formation of nitramine and nitrosamine in the nitration/nitrosation process of DMA. A hydrogen-bonding intermediate ([(CH 3) 2 N⋯HONO]) is initially formed when particulate DMA reacts with NO 2 followed by aminyl radical formation, and then nitr- and nitros-amine form through addition reactions with NO 2 and NO, respectively. The dimer of NO 2 (i.e., N 2 O 4) and the product of NO and NO 2 (i.e., N 2 O 3) can also react with DMA to attack the lone pair electrons on the central N atom of DMA to finally form nitr- and nitros-amine. This study helps reveal the nitration reaction mechanism of organic amines in the particle phase. It also aids in understanding the process of nitrogen cycling in the atmosphere. [Display omitted] • Nitration reaction process of DMA with NO x in the particle phase was investigated. • DMA can be uptake into the acidic aerosols to form DMAH + via substitution reaction. • Nitration mechanism of particulate organic amines by NO x was proposed. • Nitr- and nitros-amine will form during the nitration reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • WO 3 and MoO 3 loadings promoted the reactivity and water resistance of V 2 O 5 /TiO 2. • The activation of NH 3ads-L1 (1284 cm−1, Ti sites) to NH 2 * was revealed by 2D COS. • NH 2 NO* intermediates were produced by the reaction of NH 3ads-L1 with NO. • WO 3 enhanced the activation of NH 3ads-L1 to NH 2 * and the formation of NH 2 NO*. • WO 3 and MoO 3 suppressed the negative effects of H 2 O on active sites of V 2 O 5 /TiO 2. Vanadia-based catalysts have been widely applied in NO x reduction, while the promoting effects of WO 3 and MoO 3 are still under debate. Herein, we prepared V 2 O 5 /TiO 2 , V 2 O 5 -WO 3 /TiO 2 , and V 2 O 5 -MoO 3 /TiO 2 catalysts and revealed that WO 3 and MoO 3 enhanced the activity of V 2 O 5 /TiO 2 , especially under wet conditions. In situ DRIFTS, two-dimensional correlation spectroscopy (2D COS), and DFT calculations demonstrated that NH 3 adsorbed on Lewis acid sites of V 2 O 5 /TiO 2 , resulting in the formation of NH 3ads-L1 (1284 cm−1, Ti sites of O=V–O–Ti) and NH 3ads-L2 (1604 cm−1, V=O sites). By using 2D COS, we found that the NH 3ads-L1 exhibited higher reactivity towards NO to produce NH 2 NO* via NH 2 *, which was promoted by WO 3. Moreover, WO 3 and MoO 3 doping inhibited H 2 O adsorption, and promoted its desorption by increasing temperature, thus protecting the V=O sites on V 2 O 5 /TiO 2. Also, 2D COS provided a new perspective for in-depth understanding of the active sites and intermediates in the NH 3 -SCR reaction. [ABSTRACT FROM AUTHOR]

The dithiothreitol (DTT) assay is the most commonly used method to quantify the oxidative potential of fine particles. However, the reported DTT decay rates of carbon black (CB) materials vary greatly among different researchers. This might have resulted from either the intrinsic toxicity of CB or the unsuitability of the DTT assay protocol for CB particles. In the current study, the protocol of the DTT assay for CB materials has been carefully evaluated. It was found that the dispersion degree of CB particles in water has a great influence on the DTT decay rate of CB materials. For CB particles (special black 4A (SB4A) and Printex U) and single-walled carbon nanotube tube (SWCNT), the DTT decay rate after sonication for 10 min became 4.2, 4.6 and 1.7 times higher than that without sonication. The rate continued to grow as a function of ultrasound time up to 30 min of sonication. Although the concentration of soluble transition metals and surface oxygen-containing species such as carbonyls increased slightly with sonication, they had no significant effects on the measured DTT activity, while the increase in the dispersion degree of aggregates was found to play a vital role in the observed enhancement of the DTT decay rates for different CB materials. Based on our results, 30 min of sonication is recommended for sample dispersion when measuring the DTT decay rate of CB materials. Unlabelled Image [ABSTRACT FROM AUTHOR]

Background: Integrin, beta-like 1 (ITGBL1) is involved in a variety of human malignancies. However, the information on the involvement of ITGBL1 in gastric carcinoma (GC) is limited. Hence, this study aimed further to explore the functions and mechanisms of ITGBL1 in GC.Methods: First, multiple bioinformatics databases, including Oncomine, Tumor Immune Estimation Resource, UALCAN, and Kaplan-Meier Plotter, were used to predict the expression level and prognostic value of ITGBL1, as well as its association with immune infiltration and epithelial-mesenchymal transition (EMT) in GC. Quantitative reverse transcription-polymerase chain reaction and immunohistochemical analysis were used to detect the expression of ITGBL1 in both GC tissues and cells. Then, targeted silencing of ITGBL1 in GC cells was further used to examine the biological functions of ITGBL1.Results: These databases revealed that ITGBL1 was overexpressed and affected the overall survival in GC. Besides, the expression of ITGBL1 positively correlated with immune-infiltrating cells and EMT-related markers. Subsequently, molecular biology experiments verified these predictions. In GC tissues and cells, ITGBL1 was notably overexpressed. Loss-of-function studies showed that the knockdown of ITGBL1 significantly suppressed migration and invasion but promoted apoptosis in MGC803 GC cells. Furthermore, the inhibition of ITGBL1 resulted in remarkably increased protein expression levels of cadherin 1, while the expression of Vimentin, Snail, and transforming growth factor-β1 was downregulated, indicating the initiation and progression of GC caused by ITGBL1 partly via inducing EMT.Conclusions: To sum up, the findings indicated that ITGBL1 acted as a valuable oncogenic factor in GC. [ABSTRACT FROM AUTHOR]

Sulfate plays an important role in atmospheric haze in China, which has received considerable attention in recent years. Various types of parameterization methods and heterogeneous oxidation rates of SO 2 have been used in previous studies. However, properly representing heterogeneous sulfate formation in air quality models remains a big challenge. In this study, we quantified the heterogeneous oxidation reaction using experimental results that approximate the haze conditions in China. Firstly, a series of experiments were conducted to investigate the heterogeneous uptake of SO 2 with different relative humidity (RH) levels and the presence of NH 3 and NO 2 on natural dust surfaces. Then the uptake coefficients for heterogeneous oxidation of SO 2 to sulfate at different RH under NH 3 and NO 2 coexistence were parameterized based on the experimental results and implemented in the Community Multiscale Air Quality modeling system (CMAQ). Simulation results suggested that this new parameterization improved model performance by 6.6% in the simulation of wintertime sulfate concentrations for Beijing. The simulated maximum growth rate of SO 4 2− during a heavy pollution period increased from 0.97 μg m−3 h−1 to 10.11 μg m−3 h−1. The heterogeneous oxidation of SO 2 in the presence of NH 3 contributed up to 23% of the sulfate concentration during heavy pollution periods. Image 1 • Uptake coefficients of SO 2 on dust with coexistence of NH 3 and NO 2 were obtained. • New parameterization was proposed based on experimental results under different RHs. • The new parameterization can improve sulfate simulation in wintertime in CMAQ. • Impact of NH 3 on heterogeneous formation of sulfate in wintertime is non-negligible. [ABSTRACT FROM AUTHOR]

Abstract Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol (SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidation processes and further affect SOA formation. Therefore, there is a need to perform more chamber studies to disclose the influence. In this work, SOA formation over a wide range of initial precursor concentrations (tens of ppb to hundreds of ppb levels) was investigated in a 30 m3 indoor smog chamber, and mainly through the analysis of multiple generations of VOCs detected from HR-ToF-PTRMS to expound the difference in the oxidation process between low and high precursor concentrations. Compared to high initial concentrations, gas-phase intermediates formed at low concentrations had a higher intensity by about one order of magnitude, and the low-volatility compounds also had a higher formation potential due to the competition between semi-volatile intermediates and precursors with oxidants. In addition, the formed SOA was more oxidized with higher f 44 value (0.14 ± 0.02) and more relevant to real atmosphere than that formed at high concentrations. This work should help to deeply understand SOA formation and improve the performance of air quality models for SOA simulation. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Aberrant glycosylation plays an important role in the progression of gastric cancer. Although many enzymes are involved in glycoconjugate synthesis, little information is known about glycosyltransferase (GT)’s alteration in gastric cancer. To give an insight into the differential expression of GTs as obtained from the TCGA database, bioinformatics analysis of 415 gastric cancer samples and 35 normal samples was performed. Using a 0.6-fold change threshold to compare GT expression in normal and cancer tissues, it was noted that 36 GTs were upregulated including POFUT1 and 30 GTs were downregulated in cancer tissues ( P < 0.01). Enriched pathway analysis indicated that POFUT1 was correlated positively with cell cycle and cell carcinoma process but correlated negatively with cell adhesion and apoptosis ( P < 0.05). Furthermore, immunohistochemistry analysis verified that 33 out of 51 tumor tissues had detectable POFUT1 expression. POFUT1-positive samples were associated with aggressive tumor phenotypes like higher T and N classification ( P = 0.026, 0.042) as well as poor differentiation ( P = 0.031). No correlation was observed between POFUT1 expression and age, gender, stage, and Lauren classification. These results suggested that POFUT1 is increased and may serve as a potential biomarker in gastric cancer. [ABSTRACT FROM AUTHOR]

The cancer survivor population is growing due to advances in detection and treatment. For improved long-term patient management, it is critical to examine the clinical characteristics and outcomes of second primary malignancies (SPMs). An SPM is defined as a second distinct pathological diagnosis, with the same or different origin as the first primary malignancy (FPM). In the present retrospective study, categorical clinical variables were compared between subgroups and the impact on overall survival was evaluated. A total of 1,188 patients with an FPM were included, of which 102 experienced an SPM (8.59%). When compared with the patients who did not develop an SPM, patients with an SPM were significantly older at first diagnosis, had a higher pathological stage and higher rates of biliary tract disease and thyroid disease. In addition, patients with an SPM were more likely to have received postoperative chemotherapy (28.43 vs. 12.16%, P<0.0001) and to be long-term consumers of cigarettes and alcohol (25.00 vs. 8.95%, P<0.05). In addition, an increase in the number of regimens received but not in the number of courses of chemotherapy was associated with a reduction in the time interval to SPM development. Non-small cell lung cancer (NSCLC) was the most common type of FPM (18.27%). In patients with NSCLC the occurrence of SPMs was relatively low (5.07%) and the SPM-associated mortality rate was 2.30%. Breast cancer was the second common type of FPM (12.09%). Patients with breast cancer had a relatively high likelihood of developing an SPM (9.30%), for which family history of malignancy and postoperative chemotherapy were identified as potential risk factors. Patients with stomach cancer were the most vulnerable to SPM (17.95%) and patients with digestive tract cancer had the longest time interval between the FPM and SPM development. In addition, thyroid adenoma was identified as a potential risk factor for SCLC. The findings of the present study may provide valuable guidance for the short- and long-term monitoring of FPM survivors. [ABSTRACT FROM AUTHOR]

Atmospheric particulate matters have a crucial impact on climate change, visibility and human health. In this study, a detailed characteristic of summertime PM 1 was real-time measured in south suburb of Beijing from 16th August to 16th September 2018. Averaged PM 1 concentration of 24.1 ± 18.0 μg m−3 was observed, consisting of OM (50.8%), SO 4 2− (16.0%), BC (13.2%), NO 3 − (10.2%), NH 4 + (9.2%), and Cl− (0.6%). There was an accumulation mode with a peak diameter of ∼500 nm for all the species (except BC), and OM was additionally characterized by a smaller mode of <100 nm. Elemental analysis of OM showed that the diurnal variations of H/C, O/C, N/C, and S/C were correlated to the photochemical and aqueous-phase process. Four organic factors including one hydrocarbon-like (HOA) and three oxygenated (LO-OOA, SV-OOA and MO-OOA) organic aerosol factors were identified by positive matrix factorization (PMF) analysis. The contributions of these factors varied with PM 1 concentration and their average values were 31%, 30%, 14%, and 25%, respectively. Contribution of HOA was RH-independent but decreased with the increasing PM 1 concentration, while OOA factors were a combined result of RH and O x (=O 3 +NO 2), revealing the important role of photochemical and aqueous-phase process in OA evolution. The contribution of SV-OOA with the highest S/C increased significantly with RH, indicating a certain number of S-containing organics. Our results also showed that secondary OA was the dominant species, as well as increased with the pollution level, implicating VOCs and NO x should be controlled to relieve the secondary OA pollution. • Characteristic of summertime PM 1 was real-time measured in suburb of Beijing, 2018. • Elemental analysis and PMF analysis of OA were resolved to expound its evolution. • Role of RH and photochemical process in the evolution of PM 1 species was revealed. • Contribution of secondary OA increased as the pollution level during summertime. [ABSTRACT FROM AUTHOR]