MrERF039 transcription factor plays an active role in the cold response of Medicago ruthenica as a sugar molecular switch.

Cold stress severely restricts plant development, causing significant agricultural losses. We found a critical transcription factor network in Medicago ruthenica was involved in plant adaptation to low-temperature. APETALA2/ethylene responsive factor (AP2/ERF) transcription factor MrERF039 was transcriptionally induced by cold stress in M. ruthenica. Overexpression of MrERF039 significantly increased the glucose and maltose content, thereby improving the tolerance of M. ruthenica. MrERF039 could bind to the DRE cis-acting element in the MrCAS15A promoter. Additionally, the methyl group of the 14th amino acid in MrERF039 was required for binding. Transcriptome analysis showed that MrERF039 acted as a sugar molecular switch, regulating numerous sugar transporters and sugar metabolism-related genes. In addition, we found that MrERF039 could directly regulate ß-amylase gene, UDP glycosyltransferase gene, and C2H2 zinc finger protein gene expression. In conclusion, these findings suggest that high expression of MrERF039 can significantly improve the cold tolerance of M. ruthenica root tissues during cold acclimation. Our results provide a new theoretical basis and candidate genes for breeding new legume forage varieties with high resistance.

Microscopic deposition-property relationships in microbial-induced consolidation of coal dusts.

In recent years, the preparation of new microbial dust suppressants based on microbial induced carbonate precipitation (MICP) technology through enriched urease-producing microbial communities has become a new topic in the field of coal dust control. The deposition of CaCO3 was the key to suppress coal dust. However, deposition characteristics in the field is not sufficient and the relationship between deposition characteristics and erosion resistance is not clear, which hinders the development of engineering application of new microbial dust suppressant. Therefore, based on X-CT technology, this paper observed and quantified micro-deposition of bio-consolidated coal dust with different calcium sources. Furthermore, a conceptual framework for deposition was proposed and its correlation with erosion resistance was revealed. The results showed that CaCO3 induced by calcium chloride and calcium lactate was aggregate deposited. Aggregate deposited CaCO3 was small in volume, showed the distribution of aggregation in the central area and loose outside, and mosaiced pores. CaCO3 induced by calcium nitrate was surface deposition due to attached biomass. Surface deposition was mostly large volume CaCO3 expanding from the inside out, which could cover coal dust to a high degree and completely cemented pores. In addition, the threshold detachment velocity of coal dust cemented by surface deposition was increased by 17.6-19.1% compared to aggregate deposition. This depended on the abundance and strength of CaCO3 bonding between coal dust particles under different deposition. The two-factor model based on porosity and CaCO3 coverage can well express relationship between erosion resistance and depositional characteristics. Those results will help the engineering application of MICP technology in coal dust suppression.

Glutamicibacter nicotianae AT6: A new strain for the efficient biodegradation of tilmicosin.

The degradation of tilmicosin (TLM), a semi-synthetic 16-membered macrolide antibiotic, has been receiving increasing attention. Conventionally, there are three tilmicosin degradation methods, and among them microbial degradation is considered the best due to its high efficiency, eco-friendliness, and low cost. Coincidently, we found a new strain, Glutamicibacter nicotianae sp. AT6, capable of degrading high-concentration TLM at 100 mg/L with a 97% removal efficiency. The role of tryptone was as well investigated, and the results revealed that the loading of tryptone had a significant influence on TLM removals. The toxicity assessment indicated that strain AT6 could efficiently convert TLM into less-toxic substances. Based on the identified intermediates, the degradation of TLM by AT6 processing through two distinct pathways was then proposed.

Pan-cancer analysis of TASL: a novel immune infiltration-related biomarker for tumor prognosis and immunotherapy response prediction.

BACKGROUND: New immunotherapeutic strategies based on predictors are urgently needed. Toll-like receptor adaptor interacting with SLC15A4 on the lysosome (TASL) was recently confirmed to fulfill an important role in the innate immune response. However, whether TASL is involved in tumor development and immunotherapy response prediction has not been reported. METHODS: TCGA and GTEx were used to yield transcriptional, genetic, and epigenetic levels of TASL in 33 cancer types. CIBERSORT was used to explore the correlation between TASL expression and multiple immune-related signatures and tumor-infiltrating immune cell content in different cancer types. The ability of TASL to predict tumor immunotherapy response was analyzed in seven datasets. Finally, we tested TASL expression in human glioma cell lines and tissue samples and analyzed its correlation with clinicopathological parameters. RESULTS: TASL is widely heterogeneous at the transcriptional, genetic, and epigenetic levels. High TASL expression is an independent poor prognostic factor for immune "cold" tumor Low-Grade Glioma (LGG) but an opposite factor for "hot" tumors Lung Adenocarcinoma (LUAD) and Skin Cutaneous Melanoma (SKCM). TASL may affect tumor immune infiltration by mediating tumor-infiltrating lymphocytes and tumor-associated macrophages. It may differentially affect the prognosis of the three cancers by regulating the immunosuppressive microenvironment in LGG and the immunostimulatory microenvironment in LUAD and SKCM. High TASL expression is a potential biomarker for the positive response to immunotherapy in cancers such as SKCM and was also experimentally confirmed to be positively associated with adverse clinicopathological features of gliomas. CONCLUSION: TASL expression is an independent prognostic factor for LGG, LUAD, and SKCM. High TASL expression is a potential biomarker for the positive response to immunotherapy in certain cancer types such as SKCM. Further basic studies focusing on TASL expression and tumor immunotherapy are urgently needed.

Recent advancements in encapsulation of chitosan-based enzymes and their applications in food industry.

Enzymes are readily inactivated in harsh micro-environment due to changes in pH, temperature, and ionic strength. Developing suitable and feasible techniques for stabilizing enzymes in food sector is critical for preventing them from degradation. This review provides an overview on chitosan (CS)-based enzymes encapsulation techniques, enzyme release mechanisms, and their applications in food industry. The challenges and future prospects of CS-based enzymes encapsulation were also discussed. CS-based encapsulation techniques including ionotropic gelation, emulsification, spray drying, layer-by-layer self-assembly, hydrogels, and films have been studied to improve the encapsulation efficacy (EE), heat, acid and base stability of enzymes for their applications in food, agricultural, and medical industries. The smart delivery design, new delivery system development, and in vivo releasing mechanisms of enzymes using CS-based encapsulation techniques have also been evaluated in laboratory level studies. The CS-based encapsulation techniques in commercial products should be further improved for broadening their application fields. In conclusion, CS-based encapsulation techniques may provide a promising approach to improve EE and bioavailability of enzymes applied in food industry.HighlightsEnzymes play a critical role in food industries but susceptible to inactivation.Chitosan-based materials could be used to maintain the enzyme activity.Releasing mechanisms of enzymes from encapsulators were outlined.Applications of encapsulated enzymes in food fields was discussed.

Effect of surfactant on urease-producing flora from waste activated sludge using microbially induced calcite precipitation technology to suppress coal dust.

The wettability of microbially induced calcite precipitation (MICP) is a challenge in dust suppression. Herein, the tolerance of urease-producing flora to surfactants was investigated. The optimal tolerance concentrations of the urease-producing flora to sodium dodecylbenzene sulfonate (SDBS, anionic surfactant), alkyl polyglycoside (APG, non-ionic surfactant), and cocamidopropyl betaine (CAB, zwitterionic surfactant), and were 0.2%, 0.1%, and 0.05%. The cetyltrimethylammonium bromide (CTAB, cationic surfactant) inhibited urease production by urease-producing flora. The mineralization products of SDBS, APG, and CAB treatments were all transformed into calcite. The wind resistance test showed that the mass loss of all samples is less than 0.1%. The rain resistance and hardness tests showed that 0.2% SBDS had the best effect, followed by 0.1% APG and 0.05% CAB, and finally, No surfactants. Microbiome analysis showed that the abundance of Sporosarcina and Unclassified_bacillaceae reduced, and the intense competition between Paenalcaligenes and Sporosarcina are essential reasons for reducing urease activity. SDBS and APG could reduce the pathogenic risk of microbial dust suppressants. This study will facilitate the practical application of microbial dust suppressants.

Application of urease-producing microbial community in seawater to dust suppression in desert.

In order to solve the dust problem caused by sandstorms, this paper aims to propose a new method of enriching urease-producing microbial communities in seawater in a non-sterile environment. Besides, the difference of dust suppression performance of enriched microorganisms under different pH conditions was also explored to adapt the dust. The Fourier-transform infrared spectrometry (FTIR) and Scanning electron microscopy (SEM) confirmed the formation of CaCO3. The X-ray diffraction (XRD) further showed that the crystal forms of CaCO3 were calcite and vaterite. When urease activity was equivalent, the alkaline environment was conducive to the transformation of CaCO3 to more stable calcite. The mineralization rate at pH = 10 reached the maximum value on the 7th day, which was 97.49 ± 1.73%. Moreover, microbial community analysis results showed that the relative abundance of microbial community structure was different under different pH enrichment. Besides, the relative abundance of Sporosarcina, a representative genus of urease-producing microbial community, increased with the increase of pH under culture conditions, which consistent with the mineralization performance results. In addition, the genus level species network diagram also showed that in the microbial community, Sporosarcina was negatively correlated with another urease-producing genus Bacillus, and had a reciprocal relationship with Atopostipes, which means that the urease-producing microbial community was structurally stable. The enrichment of urease-producing microbial communities in seawater will provide empirical support for the large-scale engineering application of MICP technology in preventing and controlling sandstorms in deserts.

Synergistic interactions of microbial fuel cell and microbially induced carbonate precipitation technology with molasses as the substrate.

The application of microbially induced carbonate precipitation (MICP) technology is critical, but many challenges remain. In this paper, a microbial fuel cell (MFC) is used to treat molasses wastewater, and the effluent is used as the substrate to promote the growth of urease-producing bacteria. The results showed that the maximum voltage of MFC was 500 mV, and the maximum power density was 169.86 mW/m2. The mineralization rate reached 100% on the 15th day, and the mineralized product was calcite CaCO3. According to the microbial community analysis, the unclassified_Comamondaceae, Arcobacter, and Aeromonas, which could improve the OH-, signal molecular transmission and small molecular nutrients to promote the urease activity of urease-producing bacteria. The above conclusions provide a new way to reuse molasses wastewater efficiently and to apply MICP technology in dust suppression.

The Potential Mechanism of Cannabidiol (CBD) Treatment of Epilepsy in Pentetrazol (PTZ) Kindling Mice Uncovered by Multi-Omics Analysis.

Cannabidiol (CBD) is the main active ingredient in the cannabis plant used for treating epilepsy and related diseases. However, how CBD ameliorates epilepsy and its effect on the hippocampus remains unknown. Herein, we evaluated how CBD ameliorates seizure degree in pentylenetetrazol (PTZ) induced epilepsy mice after being exposed to CBD (10 mg/kg p.o). In addition, transcriptome and metabolomic analysis were performed on the hippocampus. Our results suggested that CBD could alleviate PTZ-induced seizure, of which the NPTX2, Gprc5c, Lipg, and Stc2 genes were significantly down-regulated in mice after being exposed to PTZ. Transcriptome analysis showed 97 differently expressed genes (CBD) and the PTZ groups. Metabonomic analysis revealed that compared with the PTZ group, 41 up-regulated and 67 down-regulated metabolites were identified in the hippocampus of epileptic mice exposed to CBD. The correlation analysis for transcriptome and metabolome showed that (±) 15-HETE and carnitine C6:0 were at the core of the network and were involved in the positive or negative regulation of the related genes after being treated with CBD. In conclusion, CBD ameliorates epilepsy by acting on the metabolism, calcium signaling pathway, and tuberculosis pathways in the hippocampus. Our study provided a practical basis for the therapeutic potential of treating epilepsy using CBD.

Performance optimization and mechanism analysis of applied Enteromorpha-based composite dust suppressant.

In order to solve the problem of environmental pollution caused by the escape of coal dust in open-pit coal mines, a composite dust suppressant was prepared from Enteromorpha, and the preparation factors (water-soluble polymer, temperature, solid content and surfactant) were optimized. The mechanism of dust suppression and the possibility of large-scale field application were discussed. The research results on the related properties of dust suppressants showed that the performance of Enteromorpha-based dust suppressants prepared by this method was excellent compared with similar studies. Among them, polyacrylamide (PAM) Enteromorpha-based dust suppressant had the best performance, with viscosity of 25.1 mPa s and surface tension of 27.05 mN/m. Moreover, PAM Enteromorpha-based dust suppressant had the best effect, with the mass loss of 2.94% under the wind speed of 10 m/s and the coal dust loss rate of 4.6% after rain erosion, and it had strong water retention performance. Through the discussion of dust suppression mechanism, it was found that the mechanical entangled network structure with hydrogen bonds as nodes was formed after the graft copolymerization of PAM and Enteromorpha. It had high permeability and good adhesion. After quickly wetting coal dust, it formed a dense package for coal dust. The field experiment also showed that the use of Enteromorpha-based dust suppressant can effectively inhibit the escape of coal dust. From the point of view of economy and efficiency, Enteromorpha can save 30% of the material cost and the dust suppression efficiency can reach 89-94%. Therefore, the Enteromorpha-based dust suppressant may stably suppress coal dust on the basis of reducing the cost.

Characterization and identification of the metabolites of dihydromethysticin by ultra-high-performance liquid chromatography orbitrap high-resolution mass spectrometry.

Dihydromethysticin, a natural component from Piper methysticum Forst, has been reported to display pharmacological effects in mental disorders and some malignant tumors. However, the metabolism of this component remained unknown. The goal of this work was conducted to discover the metabolic profiles of dihydromethysticin. The in vitro incubation was performed by incubating dihydromethysticin with rat, monkey, and human liver microsomes and hepatocytes. An analytical assay of ultra-high performance liquid chromatography combined with Orbitrap high-resolution mass spectrometry was utilized to detect and identify the metabolites. With high resolution mass spectrometric determination, the accurate mass, elemental composition, and product ions of the metabolites were determined, which enabled structural characterization to become easy. Under the present conditions, four phase-I metabolites, as well as six phase-II metabolites, were detected and their tentative structures were characterized by mass spectra. M4 was found as the most abundant metabolite both in liver microsomes and hepatocytes. Cytochrome P450 1A2, 2C9, and 3A4 contributed to the formation of this metabolite by using human recombinant P450 enzymes. M4 can be oxidized into reactive ortho-quinone intermediate followed by conjugating with glutathione. M4 was also subject to glucuronidation (M1 and M2) and methylation (M5). Demethylenation, oxidation, hydroxylation, glucuronidation, glutathionylation, and methylation were the primary metabolic pathways of dihydromethysticin. This study provides in vitro metabolism data of dihydromethysticin, which is indispensable for understanding the disposition of this compound.

Differences in gene expression and endophytic bacterial diversity in Atractylodes macrocephala Koidz. rhizomes from different growth years.

Atractylodes macrocephala Koidz. (AMK) is widely used in traditional Chinese medicine owing to its pharmacological activity. Here, we aimed to characterize the differentially expressed genes (DEGs) of one- and three-year growth (OYG and TYG) rhizomes of AMK, combined with endophytic bacterial diversity analysis using high-throughput RNA sequencing. A total of 114 572 unigenes were annotated using six public databases. In all, 3570 DEGs revealed a clear difference, of which 936 and 2634 genes were upregulated and downregulated, respectively. The results of KEGG pathway analysis indicated that DEGs corresponding to terpenoid synthesis gene were downregulated in TYG rhizomes. In addition, 414 424 sequences corresponding to the 16S rRNA gene were divided into 1267 operational taxonomic units (OTUs). Moreover, the diversity of endophytic bacteria changed with species in the OYG (773) and TYG (1201) rhizomes at the OTU level, and Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla. A comparison of species differences among different growth years revealed that some species were significantly different, such as Actinomycetes, Variovorax, and Cloacibacterium. Interestingly, the decrease in the function-related metabolism of terpenoids and polyketides was correlated with the low expression of terpene synthesis genes in TYG rhizomes, as assessed using PICRUSt2. These data provide a scientific basis for elucidating the mechanisms underlying metabolite accumulation and endophytic bacterial diversity in relation to the growth years in AMK.

[Chemical pattern recognition of Atractylodes chinensis from different producing areas and establishment of quantitative analysis of multi-components by single marker (QAMS) method for four components].

This study established the fingerprint and combined it with chemical pattern recognition to evaluate the quality of Atractylodes chinensis samples from different producing areas and then employed the quantitative analysis of multi-components by single marker(QAMS) method to verify the feasibility and applicability of the established method in the quality evaluation of A. chinensis. The fingerprints of A. chinensis samples were constructed via high performance liquid chromatography(HPLC) to evaluate the inter-batch consistency. With the quality control component atractylodin as the internal reference, the relative correction factors(RCFs) were established for atractylenolide Ⅰ, atractylenolide Ⅲ, and ß-eudesmol and the content of the four components was calculated. The external standard method was used to verify the accuracy of QAMS method. The quality of A. chinensis was further evaluated by similarity analysis, clustering analysis, and principal component analysis. The fingerprints of 13 batches of samples were calibrated with 21 common peaks, and 4 common peaks were identified with the similarities all above 0.9. The RCFs established with atractylodin as the internal reference represented good reproducibility under different experimental conditions. Specifically, the RCFs of atractylenolide Ⅰ, atractylenolide Ⅲ, and ß-eudesmol in A. chinensis were 2.091, 4.253, and 6.010, respectively. QAMS and ESM showed no significant difference in the results, indicating that the QAMS method established in this study was stable and reliable. Thus, HPLC fingerprint combined with QAMS can be used for the quality evaluation of A. chinensis, providing a basis for comprehensive and rapid quality evaluation of A. chinensis.

Environment-friendly dual-network hydrogel dust suppressant based on xanthan gum, polyvinyl alcohol and acrylic acid.

Hydrogen bonding interactions among poly vinyl alcohol (PVA), xanthan gum (XG) and acrylic acid (AA) molecules have been utilized to prepare an environment-friendly interpenetrating double-network hydrogel dust suppressant (PVA-XG-PAA/SDBS) with the aim of enhancing the poor mechanical performance of current hydrogel dust suppressants. A single factor test was used to determine the optimal formulation conditions for the PVA-XG-PAA/SDBS, and the viscosity, surface tension, compression strength, wind resistance, water retention and biodegradability of the samples were measured. The results showed that the hydrogel with optimal usage contained 1.5 g, 0.1 g, and 6 g of PVA, XG and AA, respectively and the optimal reaction temperature was 55 °C. Under the optimal conditions, the viscosity was 45 mPa s, the surface tension was 30 mN/m, the compression strength of the dust suppressant-solidified coal pillar reached 126 kPa, and the degradation rate at the 8th cycle (40 days) after being buried in soil was 34%. Compared with a conventional hydrogel dust suppressant, like poly acrylic acid (PAA), and the dust suppressant sodium dodecyl benzene sulfonate (SDBS), the PVA-XG-PAA/SDBS showed better water retention, wind erosion resistance, and dust-solidifying properties. On the basis of these remarkable properties, the PVA-XG-PAA/SDBS is applicable for dust prevention during coal mining, transport, and storage, which enhances the dust suppression efficiency obviously and has significant meaning to the sustainable development of the coal mining industry while protecting the environment.

LncRNA HOTTIP facilitates the stemness of breast cancer via regulation of miR-148a-3p/WNT1 pathway.

Emerging evidence suggests that dysregulation of long non-coding RNA (lncRNA) plays a key role in tumorigenesis. The lncRNA, HOXA transcript at the distal tip (HOTTIP), has been reported to be up-regulated in multiple cancers, including breast cancer, and is involved in various biological processes, including the maintenance of stemness. However, the biological function and underlying modulatory mechanism of HOTTIP in breast cancer stem cells (BCSCs) remains unknown. In this study, we found that HOTTIP was markedly up-regulated in BCSCs and had a positive correlation with breast cancer progression. Functional studies revealed that overexpression of HOTTIP markedly promoted cell clonogenicity, increased the expression of the stem cell markers, OCT4 and SOX2, and decreased the expression of the differentiation markers, CK14 and CK18, in breast cancer cells. Knockdown of HOTTIP inhibited the CSC-like properties of BCSCs. Consistently, depletion of HOTTIP suppressed tumour growth in a humanized model of breast cancer. Mechanistic studies demonstrated that HOTTIP directly binds to miR-148a-3p and inhibits the mediation of WNT1, which leads to inactivation of the Wnt/ß-catenin signalling pathway. Our study is the first to report that HOTTIP regulates the CSC-like properties of BCSCs by as a molecular sponge for miR-148a-3p to increase WNT1 expression, offering a new target for breast cancer therapy.

Expression signature of six-snoRNA serves as novel non-invasive biomarker for diagnosis and prognosis prediction of renal clear cell carcinoma.

Increasing evidence has verified that small nucleolar RNAs (snoRNAs) play significant roles in tumorigenesis and exhibit prognostic value in clinical practice. In the study, we analysed the expression profile and clinical relevance of snoRNAs from TCGA database including 530 ccRCC (clear cell renal cell carcinoma) and 72 control cases. By using univariate and multivariate Cox analysis, we established a six-snoRNA signature and divided patients into high-risk or low-risk groups. We found patients in high-risk group had significantly shorter overall survival and recurrence-free survival than those in low-risk group in test series, validation series and entire series by Kaplan-Meier analysis. We also confirmed this signature had a great accuracy and specificity in 64 clinical tissue cases and 50 serum samples. Then, depending on receiver operating characteristic curve analysis we found the six-snoRNA signature was an superior indicator better than conventional clinical factors (AUC = 0.732). Furthermore, combining the signature with TNM stage or Fuhrman grade were the optimal indicators (AUC = 0.792; AUC = 0.800) and processed the clinical applied value for ccRCC. Finally, we found the SNORA70B and its hose gene USP34 might directly regulate Wnt signalling pathway to promote tumorigenesis in ccRCC. In general, our study established a six-snoRNA signature as an independent and superior diagnosis and prognosis indicator for ccRCC.

Identification of a panel of mitotic spindle-related genes as a signature predicting survival in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is one of the most malignant tumor types worldwide. Our objective was to identify a genetic signature that could predict the prognosis of patients with LUAD. We extracted gene data sets from The Cancer Genome Atlas and obtained differentially expressed genes that were highly expressed at every stage. These genes were analyzed using gene set enrichment analysis to obtain four biological processes associated with LUAD. Subsequently, Cox univariate and multivariate analyses were performed to generate four optimized models (G2M checkpoint, E2F targets, mitotic spindle, and glycolysis). We identified a mitotic spindle-related signature (KIF15, BUB1, CCNB2, CDK1, KIF4A, DLGAP5, ECT2, and ANLN), which could be an independent prognostic indicator, to predict the prognosis of patients with LUAD. This new discovery should offer opportunities to explore the pathogenesis of LUAD and prove clinically useful in predicting LUAD patient prognosis.

Development of a novel gene signature in patients without Helicobacter pylori infection gastric cancer.

Gastric cancer (GC) is one of the most fatal common cancers in worldwide. Helicobacter pylori (H. pylori) infection is closely related to the development of GC, although the mechanism is still unclear. In our study, we aim to develop a robust messenger RNA (mRNA) signature associated with H. pylori (-) GC that can sensitively and efficiently predict the prognostic. The RNA-seq expression profile and corresponding clinical data of 598 gastric cancer samples and 63 normal samples obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus database. Using gene set enrichment analysis H. pylori (+) GC and H. pylori (-) GC patients and normal samples to select certain genes for further analysis. Using univariate and multivariate Cox regression model to establish a gene signature for predicting the overall survival (OS). Finally, we identified G2/M related seven-mRNA signature (TGFB1, EGF, MKI67, ILF3, INCENP, TNPO2, and CHAF1A) closely related to the prognosis of patients with H. pylori (-) GC. The seven-mRNA signature was identified to act as an independent prognostic biomarker by stratified analysis and multivariate Cox regression analysis. It was also validated on two test groups from TCGA and GSE15460 and shown that patients with high-risk scores based on the expression of the seven mRNAs had significantly shorter survival times compared to patients with low-risk scores (P < .0001). In this study, we developed a seven-mRNA signature related to G2/M checkpoint from H. pylori (-) GCs that as an independent biomarker potentially with a good performance in predicting OS and might be valuable for the clinical management for patients with GC.

Evaluation of a New Chemical Mechanism for 2-Amino-2-methyl-1-propanol in a Reactive Environment from CSIRO Smog Chamber Experiments.

Amines are considered as an emerging class of atmospheric pollutants that are of great importance to atmospheric chemistry and new particle formation. As a typical amine, 2-amino-2-methyl-1-propanol (AMP) is one of the proposed solvents for capturing CO2 from flue gas streams in amine-based post-combustion CO2 capture plants, and it is expected to result in AMP emission and secondary product formation in the atmosphere. However, the current knowledge of its atmospheric chemistry and kinetics is poorly understood, particularly in a reactive environment. In this work, we used the CSIRO smog chamber to study the photo-oxidation of AMP in the presence of volatile organic compound (VOC)-NOx surrogate mixtures over a range of initial amine concentrations. O3 formation was significantly inhibited when AMP was added to the surrogate VOC-NOx mixtures, implying that AMP could alter known atmospheric chemical reaction pathways and the prevailing reactivity. Simultaneously, a large amount of AMP-derived secondary aerosol was formed, with a considerably high aerosol mass yield (i.e., ratio of aerosol formed to reacted AMP) of 1.06 ± 0.20. Based on updated knowledge of its kinetics, oxidation pathways, and product yields, we have developed a new mechanism (designated as CSIAMP-19), integrated it into the Carbon Bond 6 (CB6) chemical mechanism, and evaluated it against available smog chamber data. Compared with the existing AMP mechanism (designated as CarterAMP-08), the modified CB6 with CSIAMP-19 mechanism improves prediction against AMP-VOC-NOx experiments across a range of initial AMP concentrations, within ±10% model error for gross ozone production. Our results contribute to scientific understanding of AMP photochemistry and to the development of the chemical mechanism of other amines. Once some potential limitations are considered, the updated AMP reaction scheme can be further embedded into the chemical transport model for regional modeling scenarios where AMP-related emissions are of concern.

Characterization of a new smog chamber for evaluating SAPRC gas-phase chemical mechanism.

A new state-of-the-art indoor smog chamber facility (CAPS-ZJU) has been constructed and characterized at Zhejiang University, which is designed for chemical mechanism evaluation under well-controlled conditions. A series of characterization experiments were performed to validate the well-established experimental protocols, including temperature variation pattern, light spectrum and equivalent intensity (JNO2), injection and mixing performance, as well as gases and particle wall loss. In addition, based on some characterization experiments, the auxiliary wall mechanism has been setup and examined. Fifty chamber experiments were performed across a broad range of experimental scenarios, and we demonstrated the ability to utilize these chamber data for evaluating SAPRC chemical mechanism. It was found that the SAPRC-11 can well predict the O3 formation and NO oxidation for almost all propene runs, with 6 hr Δ(O3 - NO) model error of -3% ± 7%, while the final O3 was underestimated by ~20% for isoprene experiments. As for toluene and p-xylene experiments, it was confirmed that SAPRC-11 has significant improvement on aromatic chemistry than earlier version of SAPRC-07, although the aromatic decay rate was still underestimated to some extent. The model sensitivity test has been carried out, and the most sensitive parameters identified are the initial concentrations of reactants and the light intensity as well as HONO offgasing rate and O3 wall loss rate. All of which demonstrated that CAPS-ZJU smog chamber could derive high quality experimental data, and could provide insights on chamber studies and chemical mechanism development.