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1.
J Transl Med ; 22(1): 468, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38760813

ABSTRACT

BACKGROUND: Gastric intestinal metaplasia (GIM) is an essential precancerous lesion. Although the reversal of GIM is challenging, it potentially brings a state-to-art strategy for gastric cancer therapeutics (GC). The lack of the appropriate in vitro model limits studies of GIM pathogenesis, which is the issue this work aims to address for further studies. METHOD: The air-liquid interface (ALI) model was adopted for the long-term culture of GIM cells in the present work. This study conducted Immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR), transcriptomic sequencing, and mucoproteomic sequencing (MS) techniques to identify the pathways for differential expressed genes (DEGs) enrichment among different groups, furthermore, to verify novel biomarkers of GIM cells. RESULT: Our study suggests that GIM-ALI model is analog to the innate GIM cells, which thus can be used for mucus collection and drug screening. We found genes MUC17, CDA, TRIM15, TBX3, FLVCR2, ONECUT2, ACY3, NMUR2, and MAL2 were highly expressed in GIM cells, while GLDN, SLC5A5, MAL, and MALAT1 showed down-regulated, which can be used as potential biomarkers for GIM cells. In parallel, these genes that highly expressed in GIM samples were mainly involved in cancer-related pathways, such as the MAPK signal pathway and oxidative phosphorylation signal pathway. CONCLUSION: The ALI model is validated for the first time for the in vitro study of GIM. GIM-ALI model is a novel in vitro model that can mimic the tissue micro-environment in GIM patients and further provide an avenue for studying the characteristics of GIM mucus. Our study identified new markers of GIM as well as pathways associated with GIM, which provides outstanding insight for exploring GIM pathogenesis and potentially other related conditions.


Subject(s)
Metaplasia , Humans , Air , Models, Biological , Gastric Mucosa/pathology , Gastric Mucosa/metabolism , Stomach/pathology , Organoids/pathology , Stomach Neoplasms/pathology , Stomach Neoplasms/genetics , Gene Expression Regulation, Neoplastic , Transcriptome/genetics , Intestines/pathology
2.
J Adv Res ; 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38609049

ABSTRACT

INTRODUCTION: Helicobacter pylori (H. pylori) infection has been associated with gastric carcinogenesis. However, the precise involvement of LRP8, the low-density lipoprotein receptor-related protein 8, in H. pylori pathogenesis and gastric cancer (GC) remains poorly understood. OBJECTIVES: To investigate the potential role of LRP8 in H. pylori infection and gastric carcinogenesis. METHODS: Three-dimensional human-derived gastric organoids (hGO) and gastric cancer organoids (hGCO) were synthesized from the tissues obtained from human donors. In this work, multi-omics combined with in vivo and in vitro studies were conducted to investigate the potential involvement of LRP8 in H. pylori-induced GC. RESULTS: We found that H. pylori infection significantly upregulated the expression of LRP8 in human GC tissues, cells, organoids, and mouse gastric mucous. In particular, LRP8 exhibited a distinct enrichment in cancer stem cells (CSC). Functionally, silencing of LRP8 affected the formation and proliferation of tumor spheroids, while increased expression of LRP8 was associated with increased proliferation and stemness of GC cells and organoids. Mechanistically, LRP8 promotes the binding of E-cadherin to ß-catenin, thereby promoting nuclear translocation and transcriptional activity of ß-catenin. Furthermore, LRP8 interacts with the cytotoxin-associated gene A (CagA) to form the CagA/LRP8/ß-catenin complex. This complex further amplifies H. pylori-induced ß-catenin nuclear translocation, leading to increased transcription of inflammatory factors and CSC markers. Clinical analysis demonstrated that abnormal overexpression of LRP8 is correlated with a poor prognosis and resistance to 5-Fluorouracil in patients with GC. CONCLUSION: Our findings provide valuable information on the molecular intricacies of H. pylori-induced gastric carcinogenesis, offering potential therapeutic targets and prognostic markers for GC.

3.
Biochem Biophys Res Commun ; 696: 149515, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38241815

ABSTRACT

ZNF131 is a Zinc finger protein that acts as a transcription factor with oncogenic effects in multiple cancers. In this study, we aimed to explore the alternative splicing profile of ZNF131 in hepatocellular carcinoma (HCC), its regulatory effects on cell-cycle progression, and the downstream effectors. ZNF131 transcriptional profile and HCC survival analysis were conducted using data from the Cancer Genome Atlas (TCGA)-Liver Hepatocellular Cancer (LIHC) dataset. Chromatin immunoprecipitation (ChIP)-qPCR and dual-luciferase reporter assays were utilized to explore transcriptional regulation. CCK-8, colony formation and xenograft tumor models were used to study HCC tumor growth. Results showed that ZNF131 isoform 2 is upregulated in HCC tissues and its upregulation was associated with unfavorable overall survival (OS) and progression-free interval (PFI). Knockdown of endogenous ZNF131 inhibits HCC cell growth and induces G2/M cell-cycle arrest. ZNF131 binds to the SMC4 promoter by interacting with ZBTB33 and the ZBTB33 recognizing motif. ZNF131 transcriptionally activates SMC4 expression in HCC cells. The tumor-suppressive effects of ZNF131 shRNA could be partially reversed by enforced SMC4 overexpression. In summary, this study highlights the ZNF131/ZBTB33/SMC4 axis as a driver of pathological cell cycling and proliferation in HCC.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , MicroRNAs , Animals , Humans , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Cell Line, Tumor , Transcription Factors/metabolism , Cell Proliferation , Disease Models, Animal , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Adenosine Triphosphatases/metabolism , Chromosomal Proteins, Non-Histone/metabolism
4.
Front Mol Biosci ; 10: 1097694, 2023.
Article in English | MEDLINE | ID: mdl-37006616

ABSTRACT

Long noncoding RNAs (lncRNAs) possess the potential for therapeutic targeting to treat many disorders, including cancers. Several RNA-based therapeutics (ASOs and small interfering RNAs) have gained FDA approval over the past decade. And with their potent effects, lncRNA-based therapeutics are of emerging significance. One important lncRNA target is LINC-PINT, with its universalized functions and relationship with the famous tumor suppressor gene TP53. Establishing clinical relevance, much like p53, the tumor suppressor activity of LINC-PINT is implicated in cancer progression. Moreover, several molecular targets of LINC-PINT are directly or indirectly used in routine clinical practice. We further associate LINC-PINT with immune responses in colon adenocarcinoma, proposing the potential utility of LINC-PINT as a novel biomarker of immune checkpoint inhibitors. Collectively, current evidence suggests LINC-PINT can be considered for use as a diagnostic/prognostic marker for cancer and several other diseases.

5.
Oncol Res ; 32(2): 283-296, 2023.
Article in English | MEDLINE | ID: mdl-38186577

ABSTRACT

Nicotinamide adenine dinucleotide (NAD+) plays an essential role in cellular metabolism, mitochondrial homeostasis, inflammation, and senescence. However, the role of NAD+-regulated genes, including coding and long non-coding genes in cancer development is poorly understood. We constructed a prediction model based on the expression level of NAD+ metabolism-related genes (NMRGs). Furthermore, we validated the expression of NMRGs in gastric cancer (GC) tissues and cell lines; additionally, ß-nicotinamide mononucleotide (NMN), a precursor of NAD+, was used to treat the GC cell lines to analyze its effects on the expression level of NMRGs lncRNAs and cellular proliferation, cell cycle, apoptosis, and senescence-associated secretory phenotype (SASP). A total of 13 NMRGs-related lncRNAs were selected to construct prognostic risk signatures, and patients with high-risk scores had a poor prognosis. Some immune checkpoint genes were upregulated in the high-risk group. In addition, cell cycle, epigenetics, and senescence were significantly downregulated in the high-risk group. Notably, we found that the levels of immune cell infiltration, including CD8 T cells, CD4 naïve T cells, CD4 memory-activated T cells, B memory cells, and naïve B cells, were significantly associated with risk scores. Furthermore, the treatment of NMN showed increased proliferation of AGS and MKN45 cells. In addition, the expression of SASP factors (IL6, IL8, IL10, TGF-ß, and TNF-α) was significantly decreased after NMN treatment. We conclude that the lncRNAs associated with NAD+ metabolism can potentially be used as biomarkers for predicting clinical outcomes of GC patients.


Subject(s)
RNA, Long Noncoding , Stomach Neoplasms , Humans , NAD , Stomach Neoplasms/genetics , Prognosis , Biomarkers
6.
Front Genet ; 13: 869967, 2022.
Article in English | MEDLINE | ID: mdl-35754804

ABSTRACT

Gastric cancer (GC) is a highly fatal and common malignancy of the digestive system. Recent therapeutic advancements have significantly improved the clinical outcomes in GC, but due to the unavailability of suitable molecular targets, a large number of patients do not respond to the immune checkpoint inhibitors (ICI) therapy. To identify and validate potential therapeutic and prognostic targets of gastric cancer, we used the "inferCNV" R package for analyzing single-cell sequencing data (GSE112302) of GC and normal epithelial cells. First, by using LASSO, we screened genes that were highly correlated with copy number variations (CNVs). Therefrom, five gene signature (CPVL, DDC, GRTP1, ONECUT2, and PRSS21) was selected by cross-validating the prognosis and risk management with the GC RNA-seq data obtained from GEO and TCGA. Moreover, the correlation analyses between CNVs of these genes and immune cell infiltration in gastric cancer identified CPVL as a potential prognostic marker. Finally, CPVL showed high expression in gastric cancer samples and cell lines, then siRNA-mediated silencing of CPVL expression in gastric cancer cells showed significant proliferation arrest in MGC803 cells. Here, we conclude that CNVs are key regulators of the immune cells infiltration in gastric TME as well as cancer development, and CPVL could potentially be used as a prognostic and therapeutic marker in gastric cancer.

7.
J Clin Lab Anal ; 36(6): e24437, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35478418

ABSTRACT

BACKGROUND: Gastric cancer (GC) is one of the most common cancers worldwide with a poor prognosis. The tumor microenvironment (TME) serves a pivotal role in affecting the prognosis and efficacy of immunotherapy. Given the poor prognosis of GC patients and the limitation of immunotherapy, we urged to identify new prognostic and immunotherapeutic biomarkers. METHODS: The transcriptome data were downloaded from the TCGA, GEO, and GEPIA databases, and performed differential analysis of AFF3 in tumor samples and normal samples. The UALCAN, Kaplan-Meier plotter and GEPIA databases were employed to assess the correlation of AFF3 with clinicopathological characteristics and prognosis. The potential mechanism of AFF3 was explored by the GO and KEGG enrichment. The potential role of AFF3 on tumor-infiltrating immune cells (TIICs) was explored by TIMER2.0 and TISIDB. TIMER2.0 and SangerBox3.0 databases were, respectively, used to determine the correlation of AFF3 with immune checkpoint (ICs), tumor mutational burden (TMB), and microsatellite instability (MSI) in GC. RESULTS: We found significant downregulation of AFF3 in GC tissues as compared with normal tissues. However, GC patients having a higher expression of AFF3 were found to have worse clinicopathological characteristics and prognosis. Moreover, the GO enrichment analysis illustrated that AFF3 might regulate the immune cells in the TME. In addition, the AFF3 was positively correlated with TIICs, ICs, TMB, and MSI. CONCLUSION: Here, we conclude that AFF3 may be a promising potential marker for the diagnosis and prognosis of GC patients, and may influence response to ICIs by affecting TIICs and ICs expression in the TME.


Subject(s)
Stomach Neoplasms , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Humans , Immunotherapy , Nuclear Proteins , Prognosis , Stomach Neoplasms/genetics , Stomach Neoplasms/metabolism , Stomach Neoplasms/therapy , Tumor Microenvironment/genetics
8.
Dis Markers ; 2022: 7932655, 2022.
Article in English | MEDLINE | ID: mdl-35401882

ABSTRACT

Colorectal cancer (COAD) is ranked as the third most common cancer and second in terms of cancer-related deaths worldwide. Due to its poor overall survival and prognosis, the incidents of COAD are significantly increasing. Although treatment methods have greatly been improved in the last decade, it is still not good enough to have satisfactory treatment outcomes. In recent years, immunotherapy has been successful to some extent in the treatment of many cancers but still, many patients do not respond to immunotherapy. Therefore, it is essential to have a deeper understanding of the immune characteristics of the tumor microenvironment and identify meaningful immune targets. In terms of immune targets, COAD has been poorly explored; thus, in the current study, based on the immune cell infiltration score and differentially expressed genes, COAD tumors were classified into hot and cold tumors. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was used to identify hub genes, construct a prognostic model, and screen potential immune targets. In total, 12 genes (CLK3, CYSLTR2, GJA10, CYP4Z1, FAM185A, LINC00324, EEF1A1P34, EEF1B2P8, PTCSC3, MIR6780A, LINC01666, and RNU6.661P) differentially expressed between hot and cold tumors were screened out. Among them, CYSLTR2 was considered as a potential candidate gene, because it showed a significant positive correlation with immune cell infiltration and immune checkpoints (PDCD1, CD274, and CTLA4). Finally, we constructed and validated a new prognostic model for COAD showing 0.854 AUC for the ROC curve, and these results provide sufficient potential to choose CYSLTR2 as an important immune target for the prognosis of COAD.


Subject(s)
Colorectal Neoplasms , Tumor Microenvironment , Colorectal Neoplasms/genetics , Colorectal Neoplasms/immunology , Humans , Prognosis , ROC Curve , Tumor Microenvironment/immunology
9.
Drug Deliv ; 28(1): 930-942, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33975498

ABSTRACT

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is a potent anticancer drug with versatile biological activities, while the clinical translation of curcumin is severely limited due to its hydrophobicity, rapid elimination, and metabolism in the blood circulation. Herein, we aim to unravel the potential of curcumin as a synergistic agent with immunotherapy in the treatment of cancers. In an effort to minimize premature release and improve the systemic bioavailability, a superior blood stable and reduction sensitive curcumin micellar formulation, of which the release can be triggered by cancer cells, is rationally designed. We have synthesized a telodendrimer (mPEG-PLA-(LA)4) capable of forming reversible disulfide crosslinked micelles (DCMs). The curcumin loaded DCMs (Cur/DCMs) are spherical with a uniform size of 24.6 nm. The in vitro release profile demonstrates that curcumin releases significantly slower from DCMs than that from non-crosslinked micelles (NCMs), while the release can be accelerated with the increasing concentration of reducing agent glutathione (GSH). Intravenous administration of Cur/DCMs stably retains curcumin in the bloodstream and efficiently improves the systemic bioavailability. Furthermore, Cur/DCMs exhibit synergistic anticancer efficacy when combined with the anti-PD-1 antibody in an MC-38 colon cancer xenograft model. Our results potentiate the integration of blood stable curcumin nanoformulation and immunotherapy for cancer treatment.


Subject(s)
Antineoplastic Agents/pharmacokinetics , Colonic Neoplasms/drug therapy , Curcumin/pharmacokinetics , Micelles , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents, Immunological , Cell Line , Cell Line, Tumor , Chemistry, Pharmaceutical , Curcumin/administration & dosage , Delayed-Action Preparations , Drug Carriers , Drug Liberation , Drug Stability , Drug Synergism , Female , Hemolysis , Humans , Male , Mice , Mice, Inbred C57BL , Nanoparticles , Random Allocation , Rats , Rats, Sprague-Dawley , Xenograft Model Antitumor Assays
10.
Biosci Rep ; 41(4)2021 04 30.
Article in English | MEDLINE | ID: mdl-33646276

ABSTRACT

BACKGROUND: Colorectal cancer (CRC) is the most common type of gastrointestinal malignant tumour. Colorectal adenocarcinoma (COAD) - the most common type of CRC - is particularly dangerous. The role of the immune system in the development of tumour-associated inflammation and cancer has received increasing attention recently. METHODS: In the present study, we compiled the expression profiles of 262 patients with complete follow-up data from The Cancer Genome Atlas (TCGA) database as an experimental group and selected 65 samples from the Gene Expression Omnibus (GEO) dataset (of which 46 samples were with M0) as a verification group. First, we screened the immune T helper 17 (Th17) cells related to the prognosis of COAD. Subsequently, we identified Th17 cells-related hub genes by utilising Weighted Gene Co-expression Network Analysis (WGCNA) and Least Absolute Shrinkage and Selector Operation (LASSO) regression analysis. Six genes associated with the prognosis in patients with COAD were identified, including: KRT23, ULBP2, ASRGL1, SERPINA1, SCIN, and SLC28A2. We constructed a clinical prediction model and analysed its predictive power. RESULTS: The identified hub genes are involved in developing many diseases and closely linked to digestive disorders. Our results suggested that the hub genes could influence the prognosis of COAD by regulating Th17 cells' infiltration. CONCLUSIONS: These newly discovered hub genes contribute to clarifying the mechanisms of COAD development and metastasis. Given that they promote COAD development, they may become new therapeutic targets and biomarkers of COAD.


Subject(s)
Adenocarcinoma/genetics , Biomarkers, Tumor/genetics , Colorectal Neoplasms/genetics , Th17 Cells/immunology , Adenocarcinoma/immunology , Adenocarcinoma/pathology , Asparaginase/genetics , Asparaginase/metabolism , Autoantigens/genetics , Autoantigens/metabolism , Biomarkers, Tumor/immunology , Colorectal Neoplasms/immunology , Colorectal Neoplasms/pathology , Computational Biology , GPI-Linked Proteins/genetics , GPI-Linked Proteins/metabolism , Gelsolin/genetics , Gelsolin/metabolism , Humans , Intercellular Signaling Peptides and Proteins/genetics , Intercellular Signaling Peptides and Proteins/metabolism , Keratins, Type I/genetics , Keratins, Type I/metabolism , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , alpha 1-Antitrypsin/genetics , alpha 1-Antitrypsin/metabolism
11.
Oncol Res ; 29(2): 87-103, 2021.
Article in English | MEDLINE | ID: mdl-37305397

ABSTRACT

The activation of some oncogenes promote cancer cell proliferation and growth, facilitate cancer progression and metastasis by induce DNA replication stress, even genome instability. Activation of the cyclic GMP-AMP synthase (cGAS) mediates classical DNA sensing, is involved in genome instability, and is linked to various tumor development or therapy. However, the function of cGAS in gastric cancer remains elusive. In this study, the TCGA database and retrospective immunohistochemical analyses revealed substantially high cGAS expression in gastric cancer tissues and cell lines. By employing cGAS high-expression gastric cancer cell lines, including AGS and MKN45, ectopic silencing of cGAS caused a significant reduction in the proliferation of the cells, tumor growth, and mass in xenograft mice. Mechanistically, database analysis predicted a possible involvement of cGAS in the DNA damage response (DDR), further data through cells revealed protein interactions of the cGAS and MRE11-RAD50-NBN (MRN) complex, which activated cell cycle checkpoints, even increased genome instability in gastric cancer cells, thereby contributing to gastric cancer progression and sensitivity to treatment with DNA damaging agents. Furthermore, the upregulation of cGAS significantly exacerbated the prognosis of gastric cancer patients while improving radiotherapeutic outcomes. Therefore, we concluded that cGAS is involved in gastric cancer progression by fueling genome instability, implying that intervening in the cGAS pathway could be a practicable therapeutic approach for gastric cancer.


Subject(s)
Stomach Neoplasms , Humans , Animals , Mice , Stomach Neoplasms/genetics , Retrospective Studies , Signal Transduction , Cell Proliferation/genetics , DNA Damage
12.
Cancer Med ; 9(5): 1877-1889, 2020 03.
Article in English | MEDLINE | ID: mdl-31943856

ABSTRACT

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and is extremely harmful to human health. In recent years, N6-methyladenosine (m6A) RNA methylation in eukaryotic mRNA has been increasingly implicated in cancer pathogenesis and prognosis. In this study, we downloaded the expression profile and clinical information of 307 patients from The Cancer Genome Atlas database and 64 patients from the Gene Expression Omnibus (GEO) database, and univariate Cox analysis revealed that METTL14 was a prognostic m6A RNA methylation regulator. For further study on the related genes of METTL14, weighted gene co-expression network analysis was used to find the relationship between METTL14 and gene expression, and univariate Cox analysis and least absolute shrinkage and selection operator (LASSO) methods were used to identify hub genes that may be associated with HCC prognosis. The results indicated that cysteine sulfinic acid decarboxylase, glutamic-oxaloacetic transaminase 2, and suppressor of cytokine signaling 2 were key genes affecting the prognosis of HCC patients, and m6A methylation of these mRNAs may be regulated by METTL14. Finally, a nomogram was constructed based on the hub gene expression levels, and its prediction accuracy and discriminative ability were measured by the C-index and a calibration curve. In conclusion, METTL14, an m6A RNA methylation regulator, may participate in the malignant progression of HCC by adjusting the m6A of cysteine sulfinic acid decarboxylase, glutamic-oxaloacetic transaminase 2, and suppressor of cytokine signaling 2, and these genes are useful for prognostic stratification and treatment strategy development.


Subject(s)
Biomarkers, Tumor/genetics , Carcinoma, Hepatocellular/mortality , Liver Neoplasms/mortality , Nomograms , Adenosine/analogs & derivatives , Adenosine/metabolism , Carboxy-Lyases/genetics , Carcinoma, Hepatocellular/genetics , Cell Line, Tumor , Datasets as Topic , Disease Progression , Epigenesis, Genetic , Gene Expression Regulation, Neoplastic , Humans , Kaplan-Meier Estimate , Liver Neoplasms/genetics , Methylation , Methyltransferases/metabolism , RNA, Messenger/metabolism , ROC Curve , Risk Factors , Suppressor of Cytokine Signaling Proteins/genetics , Transaminases/genetics
13.
Chemosphere ; 223: 366-374, 2019 May.
Article in English | MEDLINE | ID: mdl-30784743

ABSTRACT

Insufficient dissolved oxygen (DO) concentration is recognized as one of the major factors limiting efficient nitrogen removal in constructed wetlands (CWs). This study investigated four biochar-based vertical subsurface flow constructed wetlands (VSFCWs) (system I: intermittent aeration without biochar addition; system II: intermittent aeration with biochar addition; system III: tidal flow without biochar addition; system IV: tidal flow with biochar addition) to compare the effect of oxygen supply strategies on the performance and mechanism of nitrogen removal. The results showed that NH4+N removal efficiencies were 85.83%, 87.88%, 96.19%, and 98.30% for systems I-IV respectively. The abundance of microbes involved in nitrogen transformation also increased in all VSFCWs, particularly in the tidal flow mode with biochar addition. The higher oxygen utilization rate and higher surface area provided by biochar could significantly improve microbial abundance and then enhance nitrogen removal. Most notably, the rate of nitritation (2.92, 3.82, 3.14 and 4.27 mg N L-1 h-1) was higher than that of nitration (0.51, 0.66, 0.83 and 0.89 mg N L-1 h-1) in systems I-IV, respectively, and the percentages of NO2--N denitrified via simultaneous nitrification denitrification (SND) in systems I-IV were 58.20%, 55.10%, 50.89% and 51.89%, respectively. Therefore, in addition to conventional nitrification denitrification, partial nitrification and SND via NO2--N were also the significant nitrogen transformation pathways in the four VSFCWs at high DO concentrations (2.43-6.84 mg L-1). These results demonstrated that the tidal flow biochar-based VSFCWs performed well in nitrogen removal due to efficient oxygen supplementation and enhanced microbial community abundance.


Subject(s)
Biological Oxygen Demand Analysis , Charcoal/pharmacology , Denitrification/drug effects , Oxygen/chemistry , Wetlands , Microbiota/drug effects , Nitrification , Oxygen/pharmacology
14.
Bioresour Technol ; 270: 383-390, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30243246

ABSTRACT

This study attempts to provide an improved fundamental understanding of the self-forming dynamic membrane (SFDM) filtration process in submerged anaerobic bioreactors. Excellent system performances were achieved in terms of high COD removal efficiency (∼ 90%), fast formation/reformation of SFDM (<1 h), and sustainable low-resistance (3.92 × 1010 m-1) high-flux (10-30 L/m2·h) filtration. A typical flux-variation profile consisted of an initial abruptly fast decrease followed by a gradually slow reduction, corresponding to the formation and sustainable operation period, respectively. The increase of SFDM resistance in formation period was attributable to the fast deposition of large particles on coarse-pore support materials. After SFDM formation, the subsequent increase of SFDM resistance was controlled more by the increase of specific resistance, which was firstly mainly resulted from the increasing accumulation of small particles with higher hydrophobicity and the external deposition of eEPS but later most attributable to the increase of internal release of eEPS.


Subject(s)
Bioreactors , Anaerobiosis , Filtration , Hydrophobic and Hydrophilic Interactions , Membranes, Artificial , Waste Disposal, Fluid/methods
15.
J Environ Sci (China) ; 26(3): 708-15, 2014 Mar 01.
Article in English | MEDLINE | ID: mdl-25079285

ABSTRACT

The effect of ultraviolet irradiation on generation of radicals and formation of intermediates was investigated in electrochemical oxidation of the azo-dye Orange II using a TiO2-modified ß-PbO2 electrode. It was found that a characteristic absorbance of quinonic compounds at 255 nm, which is responsible for the rate-determining step during aromatics degradation, was formed only in electrocatalytic oxidation. The dye can be oxidized by either HO radicals or direct electron transfer. Quinonic compounds were produced concurrently. The removal of TOC by photo-assisted electrocatalytic oxidation was 1.56 times that of the sum of the other two processes, indicating a significant synergetic effect. In addition, once the ultraviolet irradiation was introduced into the process of electrocatalytic oxidation, the degradation rate of quinonic compounds was enhanced by as much as a factor of two. The more efficient generation of HO radicals resulted from the introduction of ultraviolet irradiation in electrocatalytic oxidation led to the significant synergetic effect as well as the inhibiting effect on the accumulation of quinonic compounds.


Subject(s)
Azo Compounds/chemistry , Benzenesulfonates/chemistry , Water Pollutants, Chemical/chemistry , Azo Compounds/radiation effects , Benzenesulfonates/radiation effects , Catalysis , Electrochemical Techniques , Hydroxyl Radical/chemistry , Lead/chemistry , Oxidation-Reduction , Oxides/chemistry , Ruthenium Compounds/chemistry , Titanium/chemistry , Ultraviolet Rays , Water Pollutants, Chemical/radiation effects
16.
Acta Crystallogr C ; 69(Pt 1): 33-6, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23282909

ABSTRACT

In the title compound, {[Zn(C(19)H(17)N(5)O(2))(2)(H(2)O)(2)](NO(3))(2)}(n), the Zn(II) cation is located at an inversion centre within a slightly distorted octahedron, ligated by four N atoms from four N(2),N(6)-bis[(pyridin-3-yl)methyl]pyridine-2,6-dicarboxamide (L) ligands occupying a plane about the Zn(II) atom with the two water O atoms perpendicular to that. In the complex molecule, the bidentate bridging L ligands display helical R and S conformers, and link the Zn(II) cations into a one-dimensional centrosymmetric double-chain structure containing 32-membered rings. The nitrate anions reside in these rings and are involved in multiple N-H...O hydrogen-bond interactions. On excitation at 390 nm, the title compound displays a strong blue emission centred at 449 nm. Investigation of the thermal stability shows that the network structure is stable up to 420 K.

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