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The pandemic of coronavirus disease 2019 (COVID-19) urgently calls for more sensitive molecular diagnosis to improve sensitivity of current viral nuclear acid detection. We have developed an anchor primer (AP)-based assay to improve viral RNA stability by bioinformatics identification of RNase-binding site of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and implementing AP dually targeting the N gene of SARS-CoV-2 RNA and RNase 1, 3, 6. The arbitrarily primed polymerase chain reaction (AP-PCR) improvement of viral RNA integrity was supported by (a) the AP increased resistance of the targeted gene (N gene) of SARS-CoV-2 RNA to RNase treatment; (b) the detection of SARS-CoV-2 RNA by AP-PCR with lower cycle threshold values (-2.7 cycles) compared to two commercially available assays; (c) improvement of the viral RNA stability of the ORF gene upon targeting of the N gene and RNase. Furthermore, the improved sensitivity by AP-PCR was demonstrated by detection of SARS-CoV-2 RNA in 70-80% of sputum, nasal, pharyngeal swabs and feces and 36% (4/11) of urine of the confirmed cases (n = 252), 7% convalescent cases (n = 54) and none of 300 negative cases. Lastly, AP-PCR analysis of 306 confirmed and convalescent cases revealed prolonged presence of viral loading for >20 days after the first positive diagnosis. Thus, the AP dually targeting SARS-CoV-2 RNA and RNase improves molecular detection by preserving SARS-CoV-2 RNA integrity and reveals the prolonged viral loading associated with older age and male gender in COVID-19 patients.
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COVID-19/virología , Reacción en Cadena de la Polimerasa/métodos , Ribonucleasas/metabolismo , SARS-CoV-2/metabolismo , Anciano , Sitios de Unión , Femenino , Humanos , Masculino , ARN Viral/genética , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Carga ViralRESUMEN
Guizhi granules mainly treat colds and improve overall health. They are widely used in clinical practice, but their protective effect and anti-inflammatory mechanism against influenza are unclear. In this study, the therapeutic effect of Guizhi granules on influenza was verified inâ vitro. The active compounds, targets, and cellular pathways of Guizhi granules against influenza were predicted using network pharmacology. The protein-protein interaction and component-target networks identified 5 core targets (JUN, TNF-α, RELA, AKT1, and MAPK1) and components (dihydrocapsaicin, kumatakenin, calycosin, licochalcone A, and berberine). GO and KEGG enrichment analyses revealed the anti-influenza pathways of Guizhi granules as antiviral and anti-inflammatory pathways. Molecular docking further verified that the core targets and components have good or strong binding activity. Therefore, the active ingredients, targets, and molecular mechanisms of Guizhi granules involved in influenza treatment were elucidated.
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Medicamentos Herbarios Chinos , Farmacología en Red , Simulación del Acoplamiento Molecular , Antivirales/farmacología , Factor de Necrosis Tumoral alfa , Medicamentos Herbarios Chinos/farmacologíaRESUMEN
Influenza B virus is a major causative agent of respiratory disease in humans. Our study of an outbreak of influenza B virus in Wenzhou from 2011 to 2014 revealed that 163 (5.58 %) of 2921 samples were influenza B positive. Sequencing of the hemagglutinin and neuraminidase genes showed substitutions at the amino acid level. Phylogenetic analysis revealed co-circulation of the B/Victoria and B/Yamagata lineages in the Wenzhou area from 2011 to 2014. Multiple viral introductions from both Chinese and international sources played important roles in endemic co-circulation and transmission in coastal southeastern China.
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Hemaglutininas/metabolismo , Virus de la Influenza B/genética , Gripe Humana/virología , Neuraminidasa/metabolismo , Secuencia de Aminoácidos , China/epidemiología , Regulación Viral de la Expresión Génica/fisiología , Hemaglutininas/genética , Humanos , Gripe Humana/epidemiología , Datos de Secuencia Molecular , Neuraminidasa/genética , Filogenia , ARN Viral/genética , ARN Viral/aislamiento & purificación , Proteínas Virales/genética , Proteínas Virales/metabolismoRESUMEN
BACKGROUND: The single nucleotide polymorphism (SNP) rs2072408 is located in an intron of the enhancer of zeste homolog 2 (EZH2) gene. Its role in gastric cancer (GC) has not been determined. METHODS: In the present study, the genotype of (EZH2) rs2072408 and the relationship of genotype with lymph node metastasis (LNM) and the invasive depth of gastric wall (T stage) was determined in 330 patients with GC, and the association between the genotype and recurrence and survival was determined in 253 patients with GC. RESULTS: The TT genotype was identified to be significantly associated with LNM [P = 0.013; odds ratio (OR), 6.49 (95% confidence interval (CI), 1.47 - 28.59)] and T stage [T1 + T2 vs. T3 + T4, p = 0.017, OR, 3.02 (95% CI, 1.22 - 7.44)]. The overall rates of LNM and T3 + T4 stage in the present study were 70.6% and 60.6%, respectively, the rates increased 23.8% and 20.0% in patients with the TT genotype. CONCLUSIONS: These results suggest that the TT genotype of EZH2 (rs2072408) was associated with LNM and the depth of gastric wall invasion in patients with GC.
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Adenocarcinoma/genética , Biomarcadores de Tumor/genética , Proteína Potenciadora del Homólogo Zeste 2/genética , Polimorfismo de Nucleótido Simple , Neoplasias Gástricas/genética , Adenocarcinoma/mortalidad , Adenocarcinoma/secundario , Adenocarcinoma/terapia , Adulto , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Femenino , Predisposición Genética a la Enfermedad , Homocigoto , Humanos , Estimación de Kaplan-Meier , Modelos Logísticos , Metástasis Linfática , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Oportunidad Relativa , Fenotipo , Modelos de Riesgos Proporcionales , Factores de Riesgo , Neoplasias Gástricas/mortalidad , Neoplasias Gástricas/patología , Neoplasias Gástricas/terapia , Factores de Tiempo , Resultado del Tratamiento , Adulto JovenRESUMEN
This work employed a novel rotor-stator reactor (RSR) to intensify the degradation process of o-phenylenediamine (o-PDA) by ozone. The effects of different operating parameters including initial pH, temperature, rotation speed, liquid volumetric flow rate and inlet ozone concentration on the removal efficiency of o-PDA were investigated in an attempt to establish the optimum conditions. The removal efficiency was evaluated in terms of degradation ratio and chemical oxygen demand (COD) reduction ratio of the o-PDA wastewater. Results indicate that the removal efficiency decreased with increasing liquid volumetric flow rate but increased with an increase in pH and inlet ozone concentration. Also, the removal efficiency increased up to a certain level with an increase in rotation speed and temperature. Additionally, a comparison experiment was carried out in a stirred tank reactor (STR), and the results show that the degradation and COD reduction ratios reached a maximum of 94.6% and 61.2% in the RSR as compared to 45.3% and 28.6% in the STR, respectively. This work demonstrates that ozone oxidation carried out in RSR may be a promising alternative for pre-treatment of o-PDA wastewater.
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Reactores Biológicos , Ozono/química , Fenilendiaminas/química , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Oxidación-ReducciónRESUMEN
Background: There has been a gradual increase in the proportion of preterm birth in China during the past several decades. Maternal malnutrition is a significant determinant for preterm birth. Nevertheless, comprehensive studies investigating serum mineral levels during pregnancy associated with preterm birth remain scarce. This study aims to assess the associations between maternal serum mineral levels and the risk of preterm birth. Methods: This retrospective cohort study of 18,048 pregnant women used data from a tertiary hospital in China from January 2016 to December 2022. Demographic data and serum mineral concentrations in the second and third trimesters of mothers were collected from the hospital information system. Analysis was performed using restricted cubic splines and logistic regression models. Results: The proportion of preterm birth in this study was 6.01%. Phosphorus [P for overall = 0.005; P for nonlinear = 0.490; OR (95%CI) = 1.11 (1.04, 1.18)] and chlorine [P for overall = 0.002; P for nonlinear = 0.058; OR (95%CI) = 1.11 (1.03, 1.19)] showed a significant positive correlation with preterm birth in a linear fashion. Furthermore, serum levels of potassium (P for nonlinear <0.001), sodium (P for nonlinear = 0.004), and magnesium (P for nonlinear <0.001) exhibited non-linear relationships with the risk of preterm birth. Conclusion: Serum levels of some minerals during pregnancy were associated with the risk of preterm birth among pregnant women. In addition to commonly recognized micronutrients such as folic acid, iron, and vitamin D, healthcare providers should also pay attention to the levels of these minerals during pregnancy.
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HIV drug resistance compromises the ability of anti-retroviral therapy (ART) to suppress viral replication, resulting in treatment failure. This study investigates the prevalence of pre-treatment drug resistance (PDR) in newly diagnosed individuals in a prosperous city (Wenzhou) in Southeastern China. A cross-sectional investigation was carried out among 473 newly diagnosed ART-naive HIV-1-infected individuals between January and December 2022. The protease-reverse transcriptase (PR-RT) region and integrase (IN) region of HIV-1 were amplified by two separately nested PCRs, followed by sequencing. Drug resistance mutations (DRMs) and drug resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs) were analyzed. The PDR prevalence was 6.5% [95% CI: 4.4-9.1] for any anti-retroviral drug, 0.9% [95% CI: 0.3-2.3] for NRTIs, 4.1% [95% CI: 2.5-6.5] for NNRTIs, 1.8% [95% CI: 0.8-3.6] for PIs and 0.5% [95% CI: 0.1-1.8] for INSTIs. According to the subtyping results of the PR-RT region, 11 different subtypes and 31 unique recombinant forms (URFs) were found. CRF07_BC was the dominant subtype (53.7%, 233/434), followed by CRF01_AE (25.3%, 110/434). V179D (1.6%) and K103N (1.4%) were the most predominant types of NNRTI DRMs. Q58E (1.2%) and M184V (0.7%) were the most frequent PI DRMs and NRTI DRMs, respectively. The INSTI-related DRMs Y143S (causes high-level resistance to RAL) and G163K (causes low-level resistance to EVG and RAL) were found in one patient each. Given the relatively high PDR prevalence of NNRTI (4.1%), non-NNRTI-based ART may be preferred in the future. It is recommended to include genotypic resistance testing before starting ART in regions where feasible.
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Advanced oxidation processes (AOPs) using strongly oxidizing radicals are promising for wastewater treatment and gas purification. Nevertheless, the short half-life of radicals and the limited mass transfer in traditional reactors cause under-utilization of radicals and low pollutant removal efficiency. High-gravity technology (HiGee)-enhanced AOPs (HiGee-AOPs) have been demonstrated a promising way to enhance radical utilization in a rotating packed bed reactor (RPB). Here, we review the potential mechanisms of intensified radical utilization in HiGee-AOPs, structures and performance of RPB, and applications of HiGee in AOPs. The intensification mechanisms are described from three aspects: enhanced generation of radicals by efficient mass transfer, in-situ radical utilization under frequent liquid film renewal, and selective effect on radical utilization due to micromixing in RPB. Based on these mechanisms, we propose a novel High-gravity flow reaction with the essence of efficiency, in-situ, and selectivity in order to better explain the strengthening mechanisms in HiGee-AOPs. HiGee-AOPs possess great potential for treating effluent and gaseous pollutants due to characteristics of High-gravity flow reaction. We discuss the pros and cons of different RPBs and their applications to specific HiGee-AOPs. HiGee improve the following AOPs: (1) facilitate interfacial mass transfer in homogeneous AOPs, (2) enhance mass transfer to expose more catalytically active sites and mass-produce nanocatalysts for heterogeneous AOPs, (3) inhibit bubble accumulation on the electrode surface of electrochemical AOPs, (4) increase the mass transfer between liquid and catalysts in UV-assisted AOPs, (5) improve the micromixing efficiency of ultrasound-based AOPs. Strategies outlined in this paper should inspire further development of HiGee-AOPs.
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Contaminantes Ambientales , Contaminantes Químicos del Agua , Purificación del Agua , Gases , Oxidación-Reducción , Radicales Libres , Radical Hidroxilo/química , Contaminantes Químicos del Agua/análisisRESUMEN
This work presents a screening method of physical solvents for methyl mercaptan (MeSH) absorption using quantum chemical calculations. The absorption solubility and thermodynamic behaviors of dimethyl sulfoxide (DMSO), sulfolane (SUL), propylene carbonate (PC), N,N-dimethylformamide (DMF), and 1-methyl-2-pyrrolidinone (NMP) for MeSH were calculated and analyzed using the COSMO-RS model, and the absorption mechanism was probed combining the quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG). Results show that the absorption solubility of the five solvents for MeSH by COSMO-RS model calculations follow the order of NMP > PC > DMSO > SUL > DMF, and the van der Waals forces and hydrogen bond forces determine the absorption solubility of physical solvents for MeSH. In addition, the experimental results of MeSH Henry coefficients in the above five solvents follow the same order as the calculated results. However, the calculated Henry coefficients' value largely deviates from the experimental value; therefore, we believe that this calculation method is only available for qualitative screening. This work provided a feasible approach to screening high-performance physical solvents for MeSH removal.
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This study aims to investigate the association between maternal blood parameters and the risk of neonatal pathological jaundice. A retrospective case-control study of 1309 newborns and their mothers from 2019 to 2020 in a single-center tertiary hospital. All mothers received a complete routine blood test prior to delivery, and outcome was neonatal pathological jaundice. We performed stepwise logistic regression modeling to identify maternal blood factors associated with neonatal pathological jaundice. 258 neonates (19.71%) were diagnosed with pathological jaundice. Logistic regression results showed that the odds ratio for pathological jaundice in neonates of mothers with high white blood cell (WBC) count was 1.512 (95% CI 1.145-1.998; P = 0.004). Besides, neonates whose mothers had a high mean corpuscular volume (MCV) during pregnancy doubled the odds of developing pathological jaundice (OR = 1.967; 95% CI 1.043-3.711; P = 0.037). Among neonates, those whose mothers had high levels of WBC count and MCV were at increased risk of pathological jaundice. Regular obstetric examinations and routine blood tests are essential to initiate adapted care.
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Ictericia Neonatal , Ictericia , Femenino , Embarazo , Recién Nacido , Humanos , Estudios Retrospectivos , Estudios de Casos y Controles , Madres , Pruebas Hematológicas , Ictericia Neonatal/epidemiología , Ictericia/complicaciones , Factores de RiesgoRESUMEN
Controlling and mitigating infectious diseases caused by multiple pathogens or pathogens with several subtypes require multiplex nucleic acid detection platforms that can detect several target genes rapidly, specifically, sensitively, and simultaneously. Here, we develop a detection platform, termed Multiplex Assay of RPA and Collateral Effect of Cas12a-based System (MARPLES), based on multiplex nucleic acid amplification and Cas12a ssDNase activation to diagnose these diseases and identify their pathogens. We use the clinical specimens of hand, foot, and mouth disease (HFMD) and influenza A to evaluate the feasibility of MARPLES in diagnosing the disease and identifying the pathogen, respectively, and find that MARPLES can accurately diagnose the HFMD associated with enterovirus 71, coxsackievirus A16 (CVA16), CVA6, or CVA10 and identify the exact types of H1N1 and H3N2 in an hour, showing high sensitivity and specificity and 100% predictive agreement with qRT-PCR. Collectively, our findings demonstrate that MARPLES is a promising multiplex nucleic acid detection platform for disease diagnosis and pathogen identification.
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Enfermedad de Boca, Mano y Pie , Subtipo H1N1 del Virus de la Influenza A , Ácidos Nucleicos , Humanos , Sistemas CRISPR-Cas , Recombinasas , Subtipo H3N2 del Virus de la Influenza A , Sensibilidad y Especificidad , Nucleotidiltransferasas , Reacción en Cadena de la Polimerasa MultiplexRESUMEN
In 2019, a dengue outbreak occurred with 290 confirmed cases in Wenzhou, a coastal city in southeast China. To identify the origin of the dengue virus (DENV) from this outbreak, viral RNA was extracted from four serum samples and sequenced for whole genome analysis. Then, phylogenetic analysis, gene mutation, secondary structure prediction, selection pressure analysis, and recombination analysis were performed. DENV strains Cam-03 and Cam-11 were isolated from patients traveling from Cambodia, while ZJWZ-18 and ZJWZ-62 strains were isolated from local patients without a record of traveling abroad. The whole genome sequence of all four strains was 10,735 nucleotides long. Phylogenetic tree analysis showed that the four strains belonged to genotype 1 of DENV-1, but the local Wenzhou strains and imported strains clustered in different branches. ZJWZ-18 and ZJWZ-62 were closely related to strain MF033254-Singapore-2016, and Cam-03 and Cam-11 were closely related to strain AB608788-China : Taiwan-1994. A comparison of the coding regions between the local strains and the DENV-1 standard strain (EU848545-Hawaii-1944) showed 82 amino acid mutations between the two strains. A total of 55 amino acid mutations were found between the coding regions of the local and imported strains. The overall secondary structure of the 3' UTR of the local strains had changed: apparent changes in the head and tail position were observed when compared to DENV-1 standard strain. Furthermore, selection pressure analysis and recombination detection using the 4 isolates and 41 reference strains showed two credible positive selection sites and eight credible recombination events, which warrant further studies. This study may enhance the understanding of viral replication, infection, evolution, virulence, and pathogenicity of DENV.
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Virus del Dengue , Dengue , Aminoácidos , China/epidemiología , Dengue/epidemiología , Brotes de Enfermedades , Genoma Viral , Genotipo , Humanos , FilogeniaRESUMEN
In this work, a desulfurization method using natural amino acid salts (AAS), which can be green prepared by biological fermentation, is proposed to remove H2S from raw biogas. Biogas purification and fertilizer production can be simultaneously achieved to close sulfur recycle. The reaction kinetic characteristics of H2S absorption with three kinds of AAS, including potassium ß-alaninate (PA), potassium sarcosinate (PS) and potassium l-prolinate (PP) are first studied. Kinetic parameters including orders of reaction, rate constants, pre-exponential factors and activation energies are given. AAS absorbent exhibits good potential for biogas desulfurization. Higee (high gravity) technology is utilized to intensify H2S removal. The effects of operating conditions on H2S removal efficiency are investigated and PP shows the best desulfurization performance. The phytotoxicity of AAS and amino acid salt sulfide (AASS) is assessed by the germination index of mungbean seeds. PP and its salt sulfide (PPS) show relatively low phytotoxicity and their allowable agricultural feeding concentrations are below 0.08 M and 0.04 M, respectively. The desulfurization method demonstrates a green route for biogas purification to achieve sulfur recycle.
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Biocombustibles , Sulfuro de Hidrógeno , Aminoácidos , Reactores Biológicos , Sulfuro de Hidrógeno/química , Potasio , Sales (Química) , Sulfuros , Azufre/metabolismoRESUMEN
Masks have become one of the most indispensable pieces of personal protective equipment and are important strategic products during the coronavirus disease 2019 (COVID-19) pandemic. Due to the huge mask demand-supply gap all over the world, the development of user-friendly technologies and methods is urgently needed to effectively extend the service time of masks. In this article, we report a very simple approach for the decontamination of masks for multiple reuse during the COVID-19 pandemic. Used masks were soaked in hot water at a temperature greater than 56 °C for 30 min, based on a recommended method to kill COVID-19 virus by the National Health Commission of the People's Republic of China. The masks were then dried using an ordinary household hair dryer to recharge the masks with electrostatic charge to recover their filtration function (the so-called "hot water decontamination + charge regeneration" method). Three kinds of typical masks (disposable medical masks, surgical masks, and KN95-grade masks) were treated and tested. The filtration efficiencies of the regenerated masks were almost maintained and met the requirements of the respective standards. These findings should have important implications for the reuse of polypropylene masks during the COVID-19 pandemic. The performance evolution of masks during human wear was further studied, and a company (Zhejiang Runtu Co., Ltd.) applied this method to enable their workers to extend the use of masks. Mask use at the company was reduced from one mask per day per person to one mask every three days per person, and 122â500 masks were saved during the period from 20 February to 30 March 2020. Furthermore, a new method for detection of faulty masks based on the penetrant inspection of fluorescent nanoparticles was established, which may provide scientific guidance and technical methods for the future development of reusable masks, structural optimization, and the formulation of comprehensive performance evaluation standards.
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The aim of the present study was to investigate the expression, function and underlying molecular mechanism of the long noncoding (lnc) RNA RP1163G9.1 in patients with gastric adenocarcinoma (GA). The expression levels of lncRNA RP1163G9.1 were determined in 112 paired clinical GA tissues by reverse transcriptionquantitative polymerase chain reaction analysis. Subsequently, the potential clinical values of lncRNA RP1163G9.1 were analyzed with statistical methods. Additionally, the function of lncRNA RP1163G9.1 was explored at the cellular level using the Cell Counting Kit8 proliferation assay, Transwell experiments, fluorescence in situ hybridization (FISH), colony formation assay and flow cytometry. Furthermore, the function of lncRNA RP1163G9.1 was assessed in vivo using subcutaneous tumorigenesis experiments in nude mice. lncRNA RP1163G9.1 expression in GA tissues and cells was significantly decreased when compared with that in control gastric tissues (P<0.001) or gastric epithelial cells GES1 (P<0.05). This finding was associated with the depth of invasion (P=0.001), lymph node metastasis (P=0.009), tumor size (P=0.037) and immunocytochemistry marker Ki67 (P=0.010). FISH detection demonstrated that lncRNA RP1163G9.1 was primarily located in the cytoplasm. Notably, overexpression of lncRNA RP1163G9.1 significantly decreased cell proliferation (P<0.01), colony formation (P<0.01), invasion (P<0.01) and the number of cells at the Sphase of the cell cycle (P<0.05); However, it did not exert a significant effect on apoptosis (P>0.05). Furthermore, tumor formation experiments revealed that overexpression of lncRNA RP1163G9.1 inhibited cancer cell proliferation in nude mice. The present research indicated that low expression of lncRNA RP1163G9.1 may be associated with enhanced tumor proliferation and invasion in GA.
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Adenocarcinoma/genética , ARN Largo no Codificante/genética , Neoplasias Gástricas/genética , Adenocarcinoma/patología , Anciano , Movimiento Celular/genética , Proliferación Celular/genética , Supervivencia sin Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Hibridación Fluorescente in Situ , Metástasis Linfática , Masculino , Persona de Mediana Edad , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Pronóstico , Neoplasias Gástricas/patologíaRESUMEN
Circular RNAs (circRNAs) are implicated in a variety of cancers. However, the roles of circRNAs in gastric cancer (GC) remain largely unknown. In the current study, circRNAs expression profiles were screened in GC, using 5 pairs of GC and matched non-GC tissues with circRNA chip. Preliminary results were verified with quantitative PCR (qRT-PCR). Briefly, total of 713 circRNAs were differentially expressed in GC tissues vs. non-GC tissues (fold change ≥ 2.0, p < 0.05): 191 were upregulated, whereas 522 were downregulated in GC tissues. qRT-PCR analysis of randomly selected 7 circRNAs from the 713 circRNAs in 50 paired of GC vs. non-GC control tissues confirmed the microarray data. Gene ontology (GO) and KEGG pathway analyses showed that many circRNAs are implicated in carcinogenesis. Among differentially expressed circRNAs, hsa_circ_0076304, hsa_circ_0035431, and hsa_circ_0076305 had the highest magnitude of change. These results provided a preliminary landscape of circRNAs expression profile in GC.
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Biomarcadores de Tumor , ARN , Neoplasias Gástricas/genética , Transcriptoma , Adulto , Anciano , Anciano de 80 o más Años , Biología Computacional/métodos , Femenino , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Ontología de Genes , Redes Reguladoras de Genes , Humanos , Masculino , MicroARNs/genética , Persona de Mediana Edad , ARN Circular , Adulto JovenRESUMEN
For long-term operation of highly loaded biotrickling filters (BTFs), the prevention of excess biomass accumulation was essential for avoiding BTF failure. In this study, we proposed low-dose ozonation as a biomass control strategy to maintain high removal efficiencies of volatile organic compounds (VOCs) over extended operation of BTFs. To obtain an optimized biomass control strategy, the relative performance of five parallel BTFs receiving different ozone doses was determined, and the affecting mechanism of ozonation on biofilm was elucidated. Experimental results showed that the decline in ozone-free BTF performance began from day 150, which was correlated with excess biomass accumulation, abundant excretion of extracellular polymeric substances (EPS) and a decline in metabolic activity of biofilm over extended operation. Ozone of 5-10 mg m(-3) was effective in preventing excessive growth and uneven distribution of biomass, and eventually maintaining long-term stable operations. Ozone of over 20 mg m(-3) possibly inhibited microorganism growth severely, thereby deteriorating the elimination performance instead. Comparison of the biofilm EPS indicated that the presence of ozone reduce EPS contents to different extents, which was possibly beneficial for mass transfer and metabolic activity. Comparative community analysis showed that ozonation resulted in different microbial communities in the BTFs. Dyella was found to be the most abundant bacterial genera in all BTFs regardless of ozonation, indicating strong resistance to ozonation. Chryseobacterium and Burkholderia members were markedly enriched in the ozone-added biofilm, implying good adaptation to ozone presence. These findings provided an improved understanding of low-dose ozonation in maintaining a stable long-term operation of BTF.
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Contaminantes Atmosféricos/análisis , Biopelículas/efectos de los fármacos , Reactores Biológicos/microbiología , Ozono/farmacología , Compuestos Orgánicos Volátiles/análisis , Biopelículas/crecimiento & desarrollo , Biomasa , Filtración/métodos , Peso Molecular , Ozono/químicaRESUMEN
The ozonation of synthetic wastewater containing azo dye Acid Red 14 (AR 14) was investigated in a high-throughput microporous tube-in-tube microchannel reactor. The effects of design and operating parameters such as micropore size, annular channel width, liquid volumetric flow rate, ozone-containing gas volumetric flow rate, initial pH of the solution and initial AR 14 concentration on decolorization efficiency and ozone utilization efficiency were studied with the aim to optimize the operation conditions. An increase of the ozone-containing gas or liquid flow rate could greatly intensify the gas-liquid mass transfer. Reducing the micropore size and the annular channel width led to a higher mass transfer rate and was beneficial to decolorization. Decolorization efficiency increased with an increasing ozone-containing gas volumetric flow rate, as well as a decreasing liquid volumetric flow rate and initial AR 14 concentration. The optimum initial pH for AR 14 ozonation was determined as 9.0. The degradation kinetics was observed to be a pseudo-first-order reaction with respect to AR 14 concentration. The difference between the decolorization and COD removal efficiency indicated that many intermediates existed in AR 14 ozonation. The formation of six organic intermediates during ozonation was detected by GC/MS, while the concentration of nitrate and sulfate ions was determined by ion chromatography. The possible degradation mechanism of AR 14 in aqueous solution was proposed.