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1.
PLoS Pathog ; 19(1): e1011110, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36689471

RESUMO

Pseudomonas aeruginosa is an opportunistic pathogen that predominantly causes nosocomial and community-acquired lung infections. As a member of ESKAPE pathogens, carbapenem-resistant P. aeruginosa (CRPA) compromises the limited therapeutic options, raising an urgent demand for the development of lead compounds against previously-unrecognized drug targets. Biotin is an important cofactor, of which the de novo synthesis is an attractive antimicrobial target in certain recalcitrant infections. Here we report genetic and biochemical definition of P. aeruginosa BioH (PA0502) that functions as a gatekeeper enzyme allowing the product pimeloyl-ACP to exit from fatty acid synthesis cycle and to enter the late stage of biotin synthesis pathway. In relative to Escherichia coli, P. aeruginosa physiologically requires 3-fold higher level of cytosolic biotin, which can be attributed to the occurrence of multiple biotinylated enzymes. The BioH protein enables the in vitro reconstitution of biotin synthesis. The repertoire of biotin abundance is assigned to different mouse tissues and/or organ contents, and the plasma biotin level of mouse is around 6-fold higher than that of human. Removal of bioH renders P. aeruginosa biotin auxotrophic and impairs its intra-phagosome persistence. Based on a model of CD-1 mice mimicking the human environment, lung challenge combined with systemic infection suggested that BioH is necessary for the full virulence of P. aeruginosa. As expected, the biotin synthesis inhibitor MAC13772 is capable of dampening the viability of CRPA. Notably, MAC13772 interferes the production of pyocyanin, an important virulence factor of P. aeruginosa. Our data expands our understanding of P. aeruginosa biotin synthesis relevant to bacterial infectivity. In particular, this study represents the first example of an extracellular pathogen P. aeruginosa that exploits biotin cofactor as a fitness determinant, raising the possibility of biotin synthesis as an anti-CRPA target.


Assuntos
Biotina , Infecções por Pseudomonas , Animais , Humanos , Camundongos , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Vias Biossintéticas , Biotina/química , Biotina/metabolismo , Pseudomonas aeruginosa/metabolismo
2.
Int J Phytoremediation ; 26(4): 448-458, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37565667

RESUMO

Pyrite exhibits considerable potential as an adsorbent in wastewater treatment. However, few pyrite adsorbents are directly obtained from natural pyrite, as most are composite materials that require a complex preparation process. To develop a pyrite-based adsorbent with a simple preparation process, pyrite was processed by calcination at 400, 600, and 800 °C for 4 h and ball-milled into a fine powder. The adsorption properties of the pyrite powder were systematically explored. The calcined pyrite powder was characterized by SEM-EDS and XRD. The results revealed that the pyrite calcined at 600 °C exhibited excellent adsorption properties and was primarily composed of Fe7S8. The optimum conditions for Cr(VI) removal were a temperature of 45 °C, an adsorbent dosage of 1 g, an equilibration time of 60 min, and an initial pH of 3. Moreover, the calcined pyrite powder exhibited excellent reusability, and the Cr(VI) removal rate exceeded 65% after three cycles. The Cr(VI) adsorption on pyrite can be well described by the Freundlich model and pseudo-second-order kinetic equation. The calcination temperature is the main factor affecting the adsorption performance of pyrite. Therefore, the calcined pyrite powder is expected to be an excellent adsorbent for Cr(VI) in the wastewater treatment industry.


Pyrite has shown promising development prospects in the field of wastewater purification. However, the preparation of most pyrite-based adsorbents is complicated. Upon high-temperature calcination, pyrite is used in traditional Chinese medicine clinics to promote the healing of fractures. The efficiency and underlying mechanism of Cr(VI) adsorption from water using calcined pyrite was investigated. The adsorbent was prepared using a simple method and exhibited excellent adsorption performance, thus allowing its application in preparing ore-based adsorbents for water pollution treatment.


Assuntos
Cromo , Ferro , Sulfetos , Poluentes Químicos da Água , Pós , Biodegradação Ambiental , Cromo/química , Adsorção , Cinética , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio
3.
Glia ; 71(7): 1715-1728, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36971019

RESUMO

Our previous studies indicated that RhoA knockdown or inhibition could alleviate the proliferation, migration, and differentiation of Schwann cells. However, the role of RhoA in Schwann cells during nerve injury and repair is still unknown. Herein, we developed two lines of Schwann cells conditional RhoA knockout (cKO) mice by breeding RhoAflox / flox mice with PlpCre -ERT2 or DhhCre mice. Our results indicate that RhoA cKO in Schwann cells accelerates axonal regrowth and remyelination after sciatic nerve injury, which enhances the recovery of nerve conduction and hindlimb gait, and alleviates the amyotrophy in gastrocnemius muscle. Mechanistic studies in both in vivo and in vitro models revealed that RhoA cKO could facilitate Schwann cell dedifferentiation via JNK pathway. Schwann cell dedifferentiation subsequently promotes Wallerian degeneration by enhancing phagocytosis and myelinophagy, as well as stimulating the production of neurotrophins (NT-3, NGF, BDNF, and GDNF). These findings shed light on the role of RhoA in Schwann cells during nerve injury and repair, indicating that cell type-specific RhoA targeting could serve as a promising molecular therapeutic strategy for peripheral nerve injury.


Assuntos
Traumatismos dos Nervos Periféricos , Neuropatia Ciática , Camundongos , Animais , Desdiferenciação Celular , Nervo Isquiático/metabolismo , Células de Schwann/metabolismo , Neuropatia Ciática/metabolismo , Regeneração Nervosa/fisiologia , Traumatismos dos Nervos Periféricos/metabolismo
4.
Org Biomol Chem ; 21(46): 9123-9127, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-37947448

RESUMO

A sulfoxide directed C-H metalation/boration/B2Pin2 mediated reduction/Suzuki coupling process to synthesize 4-substituted dibenzothiophene (DBT) in one-pot from dibenzothiophene-5-oxide (DBTO) was developed. A variety of DBT-based heterobiaryls were prepared in satisfactory to good yields. A mechanism was proposed. The application of this methodology was demonstrated by synthesizing a luminescent material.

5.
BMC Public Health ; 23(1): 654, 2023 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-37020206

RESUMO

BACKGROUND: This study aimed to investigate the Knowledge, Attitude, and Practice (KAP) of nephrologists on the decision of renal replacement therapy (RRT), including peritoneal dialysis, hemodialysis, and kidney transplantation. METHODS: This multicenter cross-sectional study was conducted on qualified nephrologists who volunteered to participate between July and August 2022 by using a self-administered questionnaire. RESULTS: Among 327 nephrologists, the total knowledge, attitude, and practice scores were 12.03 ± 2.11/16, 58.39 ± 6.62/75, and 27.15 ± 2.74/30, respectively. Multivariate logistic regression analysis showed that the attitude score (peritoneal dialysis: OR = 1.19, 95%CI: 1.13-1.25, P < 0.001; hemodialysis: OR = 1.14, 95%CI: 1.09-1.19, P < 0.001; kidney transplantation: OR = 1.12, 95%CI: 1.07-1.16, P < 0.001), 41-50 years of age (peritoneal dialysis: OR = 0.45, 95%CI: 0.21-0,98, P = 0.045; hemodialysis: OR = 0.27, 95%CI: 0.12-0.60, P = 0.001; kidney transplantation: OR = 0.45, 95%CI:0.20-0.97, P = 0.042), and > 50 years of age (peritoneal dialysis: OR = 0.27, 95%CI: 0.08-0.84, P = 0.024; hemodialysis: OR = 0.45, 95%CI: 0.20-0.97, P = 0.042; kidney transplantation: OR = 0.24, 95%CI: 0.08-0.77, P = 0.016) were independently associated with the consideration score of peritoneal dialysis, hemodialysis, and kidney transplantation. CONCLUSION: Better attitudes may lead to more consideration by nephrologists when choosing between peritoneal dialysis, hemodialysis, and kidney transplantation and relatively less consideration by senior physicians when making decisions; in addition, having good knowledge and good attitudes may lead to better practice.


Assuntos
Falência Renal Crônica , Nefrologistas , Humanos , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Terapia de Substituição Renal , Diálise Renal , Falência Renal Crônica/terapia
6.
Altern Ther Health Med ; 29(5): 298-301, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37083651

RESUMO

Objective: The objective of this research study was to compare the safety and efficacy of bronchial artery embolization (BAE) using Embospheres alone versus Embospheres combined with gelfoam particles in patients with massive hemoptysis. Methods: A total of 127 patients with tuberculous massive hemoptysis who were scheduled to undergo BAE were recruited and divided into two groups: Embosphere group (E group, n = 57) and Embosphere combined with gelfoam particles group (E + G group, n = 70). Technical and clinical success were assessed after BAE surgery, and mortality, untoward reactions, and risk factors for clinical failure were recorded during follow-up. Results: The technical success rate was 92.99% in the E group and 97.14% in the E + G group (P = .272), with similar 1-year mortality rates of 1.76% and 2.86%, respectively (P = .684). However, the E group exhibited a lower clinical success rate compared to the E + G group (85.96% vs. 97.14%), and this difference was statistically significant (P = .020). The untoward reactions showed no statistically significant difference (all P > .05). Univariate analysis revealed that four factors were statistically significant: age (P = .028), presence of pulmonary cavity (P = .001), diabetes (P = .005), and a single use of Embosphere embolization (P = .020). Multivariate regression analysis demonstrated that embolization with Embosphere alone was a risk factor for clinical treatment failure (P = .025). Conclusion: The combination of Embosphere with gelfoam particles can significantly improve the hemostatic effect of BAE without increasing the incidence of adverse reactions.


Assuntos
Embolização Terapêutica , Esponja de Gelatina Absorvível , Humanos , Esponja de Gelatina Absorvível/uso terapêutico , Hemoptise/tratamento farmacológico , Hemoptise/etiologia , Artérias Brônquicas , Gelatina/uso terapêutico , Embolização Terapêutica/efeitos adversos , Resultado do Tratamento , Estudos Retrospectivos
7.
Phytother Res ; 37(10): 4607-4620, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37380363

RESUMO

Atractylenolide-III (AT-III) is well known as its role in antioxidant and anti-inflammatory. Present study was aimed to figure out its effects on osteoarthritis and potential mechanisms. Rat model, human osteoarthritis cartilage explants as well as rat/human chondrocyte cultures were prepared to test AT-III's effects on osteoarthritis progression and chondrocyte senescence. Potential targeted molecules of AT-III were predicted using network pharmacology and molecular docking, assessed by Western blotting and then verified with rescue experiments. AT-III treatment alleviated osteoarthritis severity (shown by OARSI grading score and micro-CT) and chondrocyte senescence (indexed by levels of SA-ß-gal, P16, P53, MMP13, ROS and ratio of healthy/collapsed mitochondrial membrane potentials). Network pharmacology and molecular docking suggested that AT-III might play role through NF-κB pathway. Further experiments revealed that AT-III reduced phosphorylation of IKKα/ß, IκBα and P65 in NF-κB pathway. As well as nuclear translocation of p65. Both in vivo and in vitro experiments indicated that AT-III's effects on osteoarthritis and anti-senescence were reversed by an NF-κB agonist. AT-III could alleviate osteoarthritis by inhibiting chondrocyte senescence through NF-κB pathway, which indicated that AT-III is a prospective drug for osteoarthritis treatment.

8.
Environ Res ; 215(Pt 2): 114299, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36096167

RESUMO

The proper disposals of spent lithium-ion batteries (LIBs) and volatile organic compounds (VOCs) both have a significant impact on the environment and human health. In this work, different morphologies of α-MnO2 catalysts are synthesized using a manganese-based compound as the precursor which is high-selectively recovered from spent lithium-ion ternary batteries. Different synthesis methods including the co-precipitation method, hydrothermal method, and impregnation method are used to prepare different morphologies of α-MnO2 catalysts and their catalytic activities of toluene oxidation are investigated. Experimental results show that MnO2-HM-140 with stacked nanorods synthesized using the hydrothermal method exhibits the best catalytic performance of toluene oxidation (T90 of 226 °C under the WHSV of 60,000 mL g-1·h-1), which could be attributed to its better redox ability at low temperature and much more abundant adsorbed oxygen species at low temperature. The adsorption abilities of toluene and the replenish rate of surface lattice oxygen can be enhanced due to the increase of oxygen vacancies on the surface of MnO2-HM-140. Furthermore, the results of in-situ DRIFTS and TD/GC-MS imply that benzoate species are the main intermediate groups and then the reaction pathway of toluene oxidation on the surface of MnO2-HM-140 is proposed.


Assuntos
Compostos de Manganês , Compostos Orgânicos Voláteis , Benzoatos , Humanos , Lítio , Manganês , Óxidos , Oxigênio , Tolueno
9.
Vet Res ; 52(1): 9, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33472667

RESUMO

Novel duck reovirus (NDRV) causes severe economic losses to the duck industry, which is characterized by hemorrhagic spots and necrotic foci of the livers and spleens. DEAD-box helicase 1 (DDX1) plays a critical role in the innate immune system against viral infection. However, the role of duck DDX1 (duDDX1) in anti-RNA virus infection, especially in the anti-NDRV infection, has yet to be elucidated. In the present study, the full-length cDNA of duDDX1 (2223 bp encode 740 amino acids) was firstly cloned from the spleen of healthy Cherry valley ducks, and the phylogenetic tree indicated that the duDDX1 has the closest relationship with Anas platyrhynchos in the bird branch. The duDDX1 mRNA was widely distributed in all tested tissues, especially in the duodenum, liver, and spleen. Overexpression of duDDX1 in primary duck embryo fibroblast (DEF) cells triggered the activation of transcription factors IRF-7 and NF-κB, as well as IFN-ß expression, and the expression of the Toll-like receptors (TLR2, TLR3, and TLR4) was significantly increased. Importantly, after overexpressing or knocking down duDDX1 and infecting NDRV in DEF cells, duDDX1 inhibits the replication of NDRV virus and also regulates the expression of pattern recognition receptors and cytokines. This indicates that duDDX1 may play an important role in the innate immune response of ducks to NDRV. Collectively, we first cloned DDX1 from ducks and analyzed its biological functions. Secondly, we proved that duck DDX1 participates in anti-NDRV infection, and innovated new ideas for the prevention and control of duck virus infection.


Assuntos
Proteínas Aviárias/genética , RNA Helicases DEAD-box/genética , Patos , Imunidade Inata , Doenças das Aves Domésticas/genética , Infecções por Reoviridae/veterinária , Reoviridae/fisiologia , Animais , Proteínas Aviárias/metabolismo , RNA Helicases DEAD-box/metabolismo , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Infecções por Reoviridae/genética , Infecções por Reoviridae/imunologia , Infecções por Reoviridae/virologia , Transdução de Sinais
10.
Environ Res ; 193: 110563, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33278468

RESUMO

Due to the sustainable use of wastes, cathode materials of spent lithium-ion batteries are recovered and used as transition metal precursors to prepare metal oxides catalysts for the oxidation of VOCs. In this work, a series of manganese-based and cobalt-based metal oxides are synthesized via different preparation methods. Catalytic activities of the catalysts prepared are investigated through complete oxidation of oxygenated VOCs and the physicochemical properties of optimum samples are characterized. Evaluation results indicate that MnOx (SY) (HT) sample prepared via hydrothermal method and CoOx (GS) (CP) synthesized via co-precipitation method had better performance, because they have higher specific surface area, higher concentration of active oxygen species and high-valence metal ion, as well as better low-temperature reducibility compared to the other multi-metal oxides used in the study. In addition, TD/GC-MS results imply that further oxidation of by-products requires high reaction temperature during VOCs oxidation.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Metais , Óxidos , Reciclagem
11.
Vet Res ; 51(1): 12, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32070432

RESUMO

High-mobility group box 1 protein (HMGB1) shows endogenous damage-associated molecular patterns (DAMPs) and is also an early warning protein that activates the body's innate immune system. Here, the full-length coding sequence of HMGB1 was cloned from the spleen of Cherry Valley duck and analyzed. We find that duck HMGB1(duHMGB1) is mostly located in the nucleus of duck embryo fibroblast (DEF) cells under normal conditions but released into the cytoplasm after lipopolysaccharide (LPS) stimulation. Knocking-down or overexpressing duHMGB1 had no effect on the baseline apoptosis rate of DEF cells. However, overexpression increased weakly apoptosis after LPS activation. In addition, overexpression strongly activated the IFN-I/IRF7 signaling pathway in DEF cells and significantly increased the transcriptional level of numerous pattern recognition receptors (PRRs), pro-inflammatory cytokines (IL-6, TNF-α), IFNs and antiviral molecules (OAS, PKR, Mx) starting from 48 h post-transfection. Overexpression of duHMGB1 strongly impacted duck virus replication, either by inhibiting it from the first stage of infection for novel duck reovirus (NDRV) and at late stage for duck Tembusu virus (DTMUV) or duck plague virus (DPV), or promoting replication at early stage for DTMUV and DPV infection. Importantly, data from duHMGB1 overexpression and knockdown experiments, time-dependent DEF cells transcriptional immune responses suggest that duHMGB1 and RIG-I receptor might cooperate to promote the expression of antiviral proteins after NDRV infection, as a potential mechanism of duHMGB1-mediated antiviral activity.


Assuntos
Proteínas Aviárias/genética , Patos/genética , Infecções por Flavivirus/veterinária , Proteína HMGB1/genética , Infecções por Herpesviridae/veterinária , Imunidade Inata/genética , Doenças das Aves Domésticas/prevenção & controle , Transdução de Sinais/genética , Sequência de Aminoácidos , Animais , Antivirais , Proteínas Aviárias/química , Proteínas Aviárias/metabolismo , Patos/metabolismo , Flavivirus , Infecções por Flavivirus/prevenção & controle , Infecções por Flavivirus/virologia , Perfilação da Expressão Gênica/veterinária , Proteína HMGB1/química , Proteína HMGB1/metabolismo , Infecções por Herpesviridae/prevenção & controle , Infecções por Herpesviridae/virologia , Mardivirus , Filogenia , Doenças das Aves Domésticas/virologia , Alinhamento de Sequência/veterinária
12.
BMC Nephrol ; 21(1): 97, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32169051

RESUMO

BACKGROUND: Growing evidence has shown that the gut-renal connection and gut microbiota dysbiosis play a critical role in immunoglobulin A nephropathy (IgAN). However, the fecal microbiome profile in Chinese patients with IgAN remains unknown. A cross-sectional study was designed for the first time to investigate the fecal microbiota compositions in patients with primary IgAN in China and to evaluate the relationship between the fecal microbiome and IgAN clinical presentation. METHODS: Fecal samples were collected from 17 IgAN patients and 18 age-, sex-, and body mass index-matched healthy controls, and bacterial DNA was extracted for 16S ribosomal RNA gene sequencing targeting the V3-V4 region. RESULTS: Fecal samples from the IgAN patients and healthy controls showed differences in gut microbiota community richness and compositions. Compared to the healthy controls, IgAN patients at the phylum level had an increased abundance of Fusobacteria, but a decreased abundance of Synergistetes. The significantly increased genera in the IgAN group were Escherichia-Shigella, Hungatella, and Eggerthella, all of which possess pathogenic potential. Furthermore, the genus Escherichia-Shigella was negatively associated with the estimated glomerular filtration rate (eGFR) but was positively associated with the urinary albumin-to-creatinine ratio (uACR). However, the genus rectale_group was present in the IgAN group with a low abundance and was negatively associated with the uACR. Functional analysis disclosed that infection-related pathways were enriched in the IgAN group. CONCLUSIONS: We demonstrate that gut microbiota dysbiosis occurs in patients with IgAN, and that changes in gut bacterial populations are closely related to IgAN clinical features, suggesting that certain specific gut microbiota may be a potential therapeutic target for IgAN.


Assuntos
Povo Asiático , Fezes/microbiologia , Microbioma Gastrointestinal , Glomerulonefrite por IGA/etnologia , Glomerulonefrite por IGA/microbiologia , Adulto , Albuminúria/urina , Bactérias/genética , Bactérias/isolamento & purificação , Creatinina/urina , Estudos Transversais , Feminino , Microbioma Gastrointestinal/genética , Taxa de Filtração Glomerular , Glomerulonefrite por IGA/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética , Análise de Sequência de RNA
13.
Clin Lab ; 64(6): 1037-1040, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29945322

RESUMO

BACKGROUND: To study the clinical effect of low molecular heparin on unexplained recurrent spontaneous abortion (URSA). METHODS: A total of 120 URSA patients were collected in our hospital from October 2015 to September 2017. They were divided into two groups: control group (n = 60) and observation group (n = 60). The patients in the control group were administered with progesterone and human chorionic gonadotropin, and the observation group with low molecular heparin. Pregnancy outcomes, incidence of complications in pregnancy and adverse drug reactions were compared in the two groups. RESULTS: The pregnancy success rate of patients in the observation group (90.00%) is higher than that in the control group (68.33%) (p < 0.05). The incidence of complications in pregnancy in the observation group (90.00%) is lower than those in the control group (68.33%) (p < 0.05). The incidence of adverse drug reactions between the patients in the observation group (20.00%) and those in the control group (23.33%) showed no significant difference (p > 0.05). CONCLUSIONS: Low molecular heparin treatment can improve pregnancy success rate and reduce the incidence of complications in the URSA patients. Low molecular heparin is characterized by safety and reliability and has potential for application in clinic.


Assuntos
Aborto Habitual/prevenção & controle , Aborto Espontâneo/prevenção & controle , Heparina de Baixo Peso Molecular/administração & dosagem , Resultado da Gravidez , Adulto , Gonadotropina Coriônica/administração & dosagem , Feminino , Humanos , Gravidez , Progesterona/administração & dosagem , Resultado do Tratamento
14.
Appl Environ Microbiol ; 82(7): 2210-8, 2016 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-26850294

RESUMO

This paper describes the microfluidic streak plate (MSP), a facile method for high-throughput microbial cell separation and cultivation in nanoliter sessile droplets. The MSP method builds upon the conventional streak plate technique by using microfluidic devices to generate nanoliter droplets that can be streaked manually or robotically onto petri dishes prefilled with carrier oil for cultivation of single cells. In addition, chemical gradients could be encoded in the droplet array for comprehensive dose-response analysis. The MSP method was validated by using single-cell isolation of Escherichia coli and antimicrobial susceptibility testing of Pseudomonas aeruginosa PAO1. The robustness of the MSP work flow was demonstrated by cultivating a soil community that degrades polycyclic aromatic hydrocarbons. Cultivation in droplets enabled detection of the richest species diversity with better coverage of rare species. Moreover, isolation and cultivation of bacterial strains by MSP led to the discovery of several species with high degradation efficiency, including four Mycobacterium isolates and a previously unknown fluoranthene-degrading Blastococcus species.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Ensaios de Triagem em Larga Escala/métodos , Microfluídica/métodos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Escherichia coli/metabolismo , Ensaios de Triagem em Larga Escala/instrumentação , Microfluídica/instrumentação , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Pseudomonas aeruginosa/metabolismo
15.
Environ Sci Technol ; 50(5): 2564-72, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26815147

RESUMO

Mercury pollution from coal-fired power plants has drawn attention worldwide. To achieve efficient catalytic oxidation of Hg(0) at both high and low temperatures, we prepared and tested novel IrO2 modified Ce-Zr solid solution catalysts under various conditions. It was found that the IrO2/Ce0.6Zr0.4O2 catalyst, which was prepared using the polyvinylpyrrolidone-assisted sol-gel method, displayed significantly higher catalytic activity for Hg(0) oxidation. The mechanism of Hg(0) removal over IrO2/Ce0.6Zr0.4O2 was studied using various methods, and the Hg(0) oxidation reaction was found to follow two possible pathways. For the new chemisorption-regeneration mechanism proposed in this study, the adsorbed Hg(0) was first oxidized with surface chemisorbed oxygen species to form HgO; the HgO could desorb from the surface of catalysts by itself or react with adsorbed HCl to be release in the form of gaseous HgCl2. O2 is indispensable for the chemisorption process, and the doping of IrO2 could facilitate the chemisorption process. In addition, the Deacon reaction mechanism was also feasible for Hg(0) oxidation: this reaction would involve first oxidizing the adsorbed HCl to active Cl species, after which the Hg(0) could react with Cl to form HgCl2. Additionally, doping IrO2 could significantly improve the Cl yield process. In summary, the novel IrO2 modified catalyst displayed excellent catalytic activity for elemental mercury oxidation, and the proposed reaction mechanisms were determined reasonably.


Assuntos
Carvão Mineral , Gases/química , Mercúrio/isolamento & purificação , Catálise , Hidrogênio/química , Irídio/química , Oxirredução , Espectroscopia Fotoeletrônica , Temperatura
16.
Environ Sci Technol ; 50(11): 5809-16, 2016 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-27123922

RESUMO

Here we demonstrate that sulfur dioxide (SO2) is efficiently captured via heterogeneous oxidation into sulfate on the surface of hydroxylated manganese dioxide (MnO2). Lab-scale activity tests in a fluidized bed reactor showed that the removal efficiency for a simulated flue gas containing 5000 mg·Nm(-3) SO2 could reach nearly 100% with a GHSV (gas hourly space velocity) of 10000 h(-1). The mechanism was investigated using a combination of experimental characterizations and theoretical calculations. It was found that formation of surface bound sulfate proceeds via association of SO2 with terminal hydroxyls. Both H2O and O2 are essential for the generation of reactive terminal hydroxyls, and the indirect role of O2 in heterogeneous SO2 oxidation at low temperature was also revealed. We propose that the high reactivity of terminal hydroxyls is attributed to the proper surface configuration of MnO2 to adsorb water with degenerate energies for associative and dissociative states, and maintain rapid proton dynamics. Viability analyses suggest that the desulfurization method that is based on such a direct oxidation reaction at the gas/solid interface represents a promising approach for SO2 capture.


Assuntos
Dióxido de Enxofre , Água , Oxirredução
17.
Phytother Res ; 30(10): 1680-1688, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27397144

RESUMO

Astragaloside I (As-I), one of the main active ingredients in Astragalus membranaceus, is believed to have osteogenic properties, but this hypothesis has not been investigated in detail. In the present work, the As-I-induced osteogenic effects and its underlying mechanism were studied in MC3T3-E1 cells. The results indicated that the cellular levels of ALP and extracellular matrix calcium increased in a dose-dependent manner by As-I. To clarify the mechanisms involved in this process, the effect of As-I on the key osteogenic-related genes was investigated. We found that As-I stimulated the expression of ß-catenin and Runx2 in MC3T3-E1 cells, which play central roles in the Wnt/ß-catenin signaling pathway, suggesting that As-I could promote osteoblastic differentiation by regulating the Wnt/ß-catenin signaling pathway. Moreover, the osteogenic effect of As-I could be inhibited by DKK-1, which is the classical inhibitor of Wnt/ß-catenin-signaling pathway. Furthermore, As-I also increased BMP-2, BGP and OPG/RANKL expression, which are also activated by Wnt/ß-catenin signaling pathway. Taken together, our findings show that As-I stimulates osteoblast differentiation through the Wnt/ß-catenin signaling pathway, which also activates the BMP pathway and RANK pathway, thus highlighting the As-I for pharmaceutical and medicinal applications such as treating bone disease. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Osteoblastos/efeitos dos fármacos , Saponinas/química , Triterpenos/química , Via de Sinalização Wnt/imunologia , Diferenciação Celular , Osteogênese/efeitos dos fármacos
18.
Breast Cancer Res ; 17: 36, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25848723

RESUMO

INTRODUCTION: Triple-negative breast cancer (TNBC) patients often face a high risk of early relapse characterized by extensive metastasis. Previous works have shown that aberrant cell surface glycosylation is associated with cancer metastasis, suggesting that altered glycosylations might serve as diagnostic signatures of metastatic potential. To address this question, we took TNBC as an example and analyzed six TNBC cell lines, derived from a common progenitor, that differ in metastatic potential. METHODS: We used a microarray with 91 lectins to screen for altered lectin bindings to the six TNBC cell lines. Candidate lectins were then verified by lectin-based flow cytometry and immunofluorescent staining assays using both TNBC/non-TNBC cancer cells. Patient-derived tissue microarrays were then employed to analyze whether the staining of Ricinus communis agglutinin I (RCA-I), correlated with TNBC severity. We also carried out real-time cell motility assays in the presence of RCA-I. Finally, liquid chromatography-mass spectrometry/tandem spectrometry (LC-MS/MS) was employed to identify the membrane glycoproteins recognized by RCA-I. RESULTS: Using the lectin microarray, we found that the bindings of RCA-I to TNBC cells are proportional to their metastatic capacity. Tissue microarray experiments showed that the intensity of RCA-I staining is positively correlated with the TNM grades. The real-time cell motility assays clearly demonstrated RCA-I inhibition of adhesion, migration, and invasion of TNBC cells of high metastatic capacity. Additionally, a membrane glycoprotein, POTE ankyrin domain family member F (POTEF), with different galactosylation extents in high/low metastatic TNBC cells was identified by LC-MS/MS as a binder of RCA-I. CONCLUSIONS: We discovered RCA-I, which bound to TNBC cells to a degree that is proportional to their metastatic capacities, and found that this binding inhibits the cell invasion, migration, and adhesion, and identified a membrane protein, POTEF, which may play a key role in mediating these effects. These results thus indicate that RCA-I-specific cell surface glycoproteins may play a critical role in TNBC metastasis and that the extent of RCA-I cell binding could be used in diagnosis to predict the likelihood of developing metastases in TNBC patients.


Assuntos
Membrana Celular/metabolismo , Lectinas de Plantas/metabolismo , Polissacarídeos/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Feminino , Humanos , Glicoproteínas de Membrana/metabolismo , Metástase Neoplásica , Ligação Proteica , Mapeamento de Interação de Proteínas , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
19.
Environ Sci Technol ; 48(20): 12199-205, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25229460

RESUMO

The slip ammonia from selective catalytic reduction (SCR) of NOx in coal-fired flue gas can result in deterioration of the utilities or even the environmental issues. To achieve selective catalytic oxidation (SCO) of slip ammonia, Ru-modified Ce-Zr solid solution catalysts were prepared and evaluated under various conditions. It was found that the Ru/Ce(0.6)Zr(0.4)O2(polyvinylpyrrolidone (PVP)) catalyst displayed significant catalytic activity and the slip ammonia was almost completely removed with the coexistence of NOx and SO2. Interestingly, the effect of SO2 on NH3 oxidation was bifacial, and the N2 selectivity of the resulting products was as high as 100% in the presence of SO2 and NH3. The mechanism of the SCO of NH3 over Ru/Ce(0.6)Zr(0.4)O2(PVP) was studied using various techniques, and the results showed that NH3 oxidation follows an internal SCR (iSCR) mechanism. The adsorbed ammonia was first activated and reacted with lattice oxygen atoms to form an -HNO intermediate. Then, the -HNO mainly reacted with atomic oxygen from O2 to form NO. Meanwhile, the formed NO interacted with -NH2 to N2 with N2O as the byproduct, but the presence of SO2 can effectively inhibit the production of N2O.


Assuntos
Poluentes Atmosféricos/química , Amônia/química , Rubídio/química , Adsorção , Catálise , Cério/química , Óxido Nítrico/química , Oxirredução , Óxidos/química , Oxigênio/química , Povidona , Espectroscopia de Infravermelho com Transformada de Fourier , Dióxido de Enxofre/química , Zircônio/química
20.
ScientificWorldJournal ; 2014: 394828, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25202723

RESUMO

In this paper, we present an implementation scheme of memristor-based multilayer feedforward small-world neural network (MFSNN) inspirited by the lack of the hardware realization of the MFSNN on account of the need of a large number of electronic neurons and synapses. More specially, a mathematical closed-form charge-governed memristor model is presented with derivation procedures and the corresponding Simulink model is presented, which is an essential block for realizing the memristive synapse and the activation function in electronic neurons. Furthermore, we investigate a more intelligent memristive PID controller by incorporating the proposed MFSNN into intelligent PID control based on the advantages of the memristive MFSNN on computation speed and accuracy. Finally, numerical simulations have demonstrated the effectiveness of the proposed scheme.


Assuntos
Algoritmos , Redes Neurais de Computação
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