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1.
Biotechnol Bioeng ; 2024 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-39468420

RESUMO

Flavin-dependent halogenase (FDH) is highly prized in pharmaceutical and chemical industries for its exceptional capacity to produce halogenated aromatic compounds with precise regioselectivity. This study has devised a multi-enzyme self-assembly strategy to construct an effective and reliable in vitro coenzyme cycling system tailored for FDHs. Initially, tri-enzyme self-assembling nanoclusters (TESNCs) were developed, comprising glucose dehydrogenase (GDH), flavin reductase (FR) and FDH. The TESNCs exhibited enhanced thermal stability and conversion efficiency compared to free triple enzyme mixtures during the conversion of L-Trp to 6-Cl-L-Trp, resulting in a 2.1-fold increase in yield. Subsequently, an ordered co-immobilization of GDH, FR, and FDH was established, further amplifying the stability and catalytic efficiency of the FDH coenzyme cycle system. Compared to the free TESNCs, the immobilized TESNCs demonstrated a 4.2-fold increase in catalytic efficiency in a 5 mL reaction system. This research provides an effective strategy for developing a robust and efficient coenzyme recycling system for FDHs.

2.
Environ Sci Technol ; 58(33): 14886-14894, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39073867

RESUMO

In this study, we investigate how temperature variations, a key environmental factor, affect the charge transfer process in FCDI systems across seasonal variation and geographical distributions, which is crucial for optimizing FCDI performance but has not received adequate attention. Therefore, thermal-assisted FCDI systems were proposed by controlling the temperatures of the flow electrode and saline water to simulate the environmental conditions, and the temperature effects on the charge transport and desalting ability of FCDI were investigated. First, the isothermal mode was performed, where the flow electrode and saline water were controlled at the same temperatures (0-50 °C) to simulate the natural atmospheric temperature fluctuations and industrial circulating cooling water system. Experimental results showed a strong positive correlation between temperature and electrosorption dynamics. Elevated temperatures significantly improved ion electromigration and diffusion, thereby enhancing the electrosorption capacity of the FCDI device. On this basis, the nonisothermal mode was designed via maintaining the temperature of the flow electrode at 50 °C to improve the desalination performance of FCDI for saline water at different temperatures (0-50 °C). Finally, the East China seawater and industrial circulating cooling water were both desalted successfully to confirm the feasibility of the temperature field in the practical application of FCDI.


Assuntos
Eletrodos , Temperatura , Purificação da Água/métodos , Água do Mar/química
3.
Ren Fail ; 46(2): 2394634, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39177235

RESUMO

OBJECTIVES: This study aims to identify risk factors for acute kidney injury (AKI) in patients with ureterolithiasis and to develop a predictive model for early AKI detection in this population. METHODS: A retrospective analysis was conducted on data from 1,016 patients with ureterolithiasis who presented to our outpatient emergency department between January 2021 and December 2022. Using multifactorial logistic regression, we identified independent risk factors for AKI and constructed a nomogram to predict AKI risk. The predictive model's efficacy was assessed through the area under the ROC curve, calibration curves, Hosmer-Lemeshow (HL) test, and decision curve analysis (DCA). RESULTS: AKI was diagnosed in 18.7% of the patients. Independent risk factors identified included age, fever, diabetes, hyperuricemia, bilateral calculi, functional solitary kidney, self-medication, and prehospital delay. The nomogram demonstrated excellent discriminatory capabilities, with AUCs of 0.818 (95% CI, 0.775-0.861) for the modeling set and 0.782 (95% CI, 0.708-0.856) for the validation set. Both calibration curve and HL test results confirmed strong concordance between the model's predictions and actual observations. DCA highlighted the model's significant clinical utility. CONCLUSIONS: The predictive model developed in this study provides clinicians with a valuable tool for early identification and management of patients at high risk for AKI, thereby potentially enhancing patient outcomes.


Assuntos
Injúria Renal Aguda , Nomogramas , Ureterolitíase , Humanos , Masculino , Feminino , Estudos Retrospectivos , Pessoa de Meia-Idade , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/diagnóstico , Fatores de Risco , Adulto , Ureterolitíase/complicações , Idoso , Curva ROC , Modelos Logísticos , Medição de Risco/métodos
4.
Ecotoxicol Environ Saf ; 249: 114367, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36508830

RESUMO

Research indicates that particulate matter with an aerodynamic equivalent diameter of less than or equal to 2.5 µm in ambient air may induce lung cancer progression. Circular RNAs are a special kind of endogenous noncoding RNA, and their functions are reflected in various diseases and physiological processes, but there are still few studies related to PM2.5-induced lung cancer. Here, we identified that circCDR1as was upregulated in lung cancer cells stimulated with PM2.5 and positively correlated with the malignant features of lung cancer. The lower expression of CircCDR1as reduced the adverse progression of lung cancer cells after PM2.5 treatment; the lower expression of circCDR1as impaired the growth size and metastatic ability of lung cancer cells in mouse tumour models. Mechanistically, circCDR1as specifically bound to serine/arginine-rich splicing Factor 1 (SRSF1) and affected the splicing of vascular endothelial growth factor-A (VEGFA) by SRSF1. Furthermore, circCDR1as affected SRSF1 function by regulating PARK2-mediated SRSF1 ubiquitination, protein production and degradation. CircCDR1as also affected C-myc and cyclin D1 expression by regulating SRSF1 and affecting the wnt/ß-catenin signalling pathway, ultimately promoting malignant behavior and inhibiting the apoptosis of lung cancer cells, thereby causing PM2.5-induced lung cancer development.


Assuntos
Neoplasias Pulmonares , Material Particulado , RNA Circular , Fatores de Processamento de Serina-Arginina , Animais , Camundongos , Modelos Animais de Doenças , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Material Particulado/toxicidade , Fator A de Crescimento do Endotélio Vascular/genética , RNA Circular/metabolismo , Fatores de Processamento de Serina-Arginina/metabolismo , Ciclina D1/genética , Ciclina D1/metabolismo , Células A549 , Humanos
5.
Angew Chem Int Ed Engl ; 62(6): e202210958, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36263900

RESUMO

The development of efficient electrocatalysts to generate key *NH2 and *CO intermediates is crucial for ambient urea electrosynthesis with nitrate (NO3 - ) and carbon dioxide (CO2 ). Here we report a liquid-phase laser irradiation method to fabricate symbiotic graphitic carbon encapsulated amorphous iron and iron oxide nanoparticles on carbon nanotubes (Fe(a)@C-Fe3 O4 /CNTs). Fe(a)@C-Fe3 O4 /CNTs exhibits superior electrocatalytic activity toward urea synthesis using NO3 - and CO2 , affording a urea yield of 1341.3±112.6 µg h-1 mgcat -1 and a faradic efficiency of 16.5±6.1 % at ambient conditions. Both experimental and theoretical results indicate that the formed Fe(a)@C and Fe3 O4 on CNTs provide dual active sites for the adsorption and activation of NO3 - and CO2 , thus generating key *NH2 and *CO intermediates with lower energy barriers for urea formation. This work would be helpful for design and development of high-efficiency dual-site electrocatalysts for ambient urea synthesis.

6.
Angew Chem Int Ed Engl ; 62(13): e202217473, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36738169

RESUMO

Atomically dispersed metal catalysts show potential advantages in N2 reduction reaction (NRR) due to their excellent activity and efficient metal utilization. Unfortunately, the reported catalysts usually exhibit unsatisfactory NRR activity due to their poor N2 adsorption and activation. Herein, we report a novel Sn atomically dispersed protuberance (ADP) by coordination with substrate C and O to induce positive charge accumulation on Sn site for improving its N2 adsorption, activation and NRR performance. The extended X-ray absorption fine structure (EXAFS) spectra confirmed the local coordination structure of the Sn ADPs. NRR activity was significantly promoted via Sn ADPs, exhibiting a remarkable NH3 yield (RNH3 ) of 28.3 µg h-1 mgcat -1 (7447 µg h-1 mgSn -1 ) at -0.3 V. Furthermore, the enhanced N2 Hx intermediates was verified by in situ experiments, yielding consistent results with DFT calculation. This work opens a new avenue to regulate the activity and selectivity of N2 fixation.

7.
Angew Chem Int Ed Engl ; 62(52): e202314414, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-37946623

RESUMO

The integration of highly active single atoms (SAs) and atom clusters (ACs) into an electrocatalyst is critically important for high-efficiency two-electron oxygen reduction reaction (2e- ORR) to hydrogen peroxide (H2 O2 ). Here we report a tandem impregnation-pyrolysis-etching strategy to fabricate the oxygen-coordinated Fe SAs and ACs anchored on bacterial cellulose-derived carbon (BCC) (FeSAs/ACs-BCC). As the electrocatalyst, FeSAs/ACs-BCC exhibits superior electrocatalytic activity and selectivity toward 2e- ORR, affording an onset potential of 0.78 V (vs. RHE) and a high H2 O2 selectivity of 96.5 % in 0.1 M KOH. In a flow cell reactor, the FeSAs/ACs-BCC also achieves high-efficiency H2 O2 production with a yield rate of 12.51±0.18 mol gcat -1 h-1 and a faradaic efficiency of 89.4 %±1.3 % at 150 mA cm-2 . Additionally, the feasibility of coupling the produced H2 O2 and electro-Fenton process for the valorization of ethylene glycol was explored in detail. The theoretical calculations uncover that the oxygen-coordinated Fe SAs effectively regulate the electronic structure of Fe ACs which are the 2e- ORR active sites, resulting in the optimal binding strength of *OOH intermediate for high-efficiency H2 O2 production.

8.
Phys Chem Chem Phys ; 24(31): 18854-18859, 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-35912834

RESUMO

Understanding the structure-activity relationship of an active site is of great significance toward the rational design of highly active catalysts. In this study, we have performed density functional theory calculations to investigate the coordination environment effect of Fe-, N-, and O-doped carbon on their nitrogen reduction reaction (NRR) properties. Our results indicate that the presence of O atoms in the coordination environment favors the activation of N2 molecules but is unfavorable to the stability, while the existence of N will weaken the adsorption of N2 and increase the reaction barrier of the first hydrogenation step. Fe-C4-C has the lowest potential for activating N2. A compromise is Fe-NxC4-x-C, where the interaction of C and N in coordination regulates the spin polarization of Fe and thus the 3d states around the Fermi level. Fe-N2C2-C was found to be the best one and NRR can proceed via the distal and alternative reaction pathways with the first hydrogenation step of N2 being the potential-limiting step and the Gibbs free energy change (ΔG) being 0.75 eV.

9.
J Cell Physiol ; 236(1): 427-439, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32583425

RESUMO

Increasing evidence suggests that long noncoding RNAs (lncRNAs) are pivotal regulators in oncogenesis. However, the role of numerous lncRNAs has never been unmasked in clear cell renal cell carcinoma (ccRCC). Presently, we investigated the function of long intergenic nonprotein coding RNA 1426 (LINC01426) in ccRCC, as The Cancer Genome Atlas data indicated that LINC01426 was highly expressed in ccRCC tissues and its overexpression was correlated with disappointing prognosis. First, we verified that LINC01426 was indeed upregulated in ccRCC cell lines and its depletion restrained ccRCC cell proliferation and migration. Besides, we proved that LINC01426 facilitated ccRCC tumorigenesis via forkhead box M1 (FOXM1). Moreover, it was revealed that miR-423-5p was downregulated and directly targeted FOXM1 in ccRCC, and that LINC01426 positively regulated FOXM1 via its inhibition on miR-423-5p. Notably, we also uncovered that miR-423-5p was transcriptionally silenced by CTBP1 and HDAC2. Of importance, LINC01426 was certified to distribute both in the cytoplasm and the nucleus of ccRCC cells, and it increased CTBP1 expression through recruiting insulin like growth factor 2 mRNA binding protein 1 (IGF2BP1) in cytoplasm whereas interacted with CTBP1 protein to improve the transcriptional repression on miR-423-5p in nucleus. Jointly, our observations unveiled that LINC01426 aggravates ccRCC progression via IGF2BP1/CTBP1/HDAC2/miR-423-5p/FOXM1 axis, highlighting LINC01426 as a novel promising target for ccRCC treatment.


Assuntos
Oxirredutases do Álcool/genética , Carcinoma de Células Renais/genética , Proteínas de Ligação a DNA/genética , Proteína Forkhead Box M1/genética , Neoplasias Renais/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Animais , Apoptose/genética , Carcinogênese/genética , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica/genética , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Regulação para Cima/genética
10.
Small ; 16(13): e1906880, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32077593

RESUMO

It is an important issue that exposed active nitrogen atoms (e.g., edge or amino N atoms) in graphitic carbon nitride (g-C3 N4 ) could participate in ammonia (NH3 ) synthesis during the photocatalytic nitrogen reduction reaction (NRR). Herein, the experimental results in this work demonstrate that the exposed active N atoms in g-C3 N4 nanosheets can indeed be hydrogenated and contribute to NH3 synthesis during the visible-light photocatalytic NRR. However, these exposed N atoms can be firmly stabilized through forming BNC coordination by means of B-doping in g-C3 N4 nanosheets (BCN) with a B-doping content of 13.8 wt%. Moreover, the formed BNC coordination in g-C3 N4 not only effectively enhances the visible-light harvesting and suppresses the recombination of photogenerated carriers in g-C3 N4 , but also acts as the catalytic active site for N2 adsorption, activation, and hydrogenation. Consequently, the as-synthesized BCN exhibits high visible-light-driven photocatalytic NRR activity, affording an NH3 yield rate of 313.9 µmol g-1 h-1 , nearly 10 times of that for pristine g-C3 N4 . This work would be helpful for designing and developing high-efficiency metal-free NRR catalysts for visible-light-driven photocatalytic NH3 synthesis.

11.
Cancer Cell Int ; 20: 274, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32595418

RESUMO

BACKGROUND: Radioresistance is an obstacle to limit efficacy of radiotherapy. Meanwhile, long non-coding RNAs (lncRNAs) have been reported to affect radioresistance. Here, we aimed to investigate lncRNAs involving radioresistance development of clear cell renal cell carcinoma (ccRCC), the most frequent type of renal cell carcinoma (RCC). METHODS: The mRNA and protein expressions of genes were measured via qRT-PCR and western blot. The relationships among genes were verified by RIP and luciferase reporter assay. The radioresistance of ccRCC cells was evaluated through clonogenic survival assay, MTT assay and TUNEL assay. RESULTS: LINC01094 was over-expressed in ccRCC cell lines. LINC01094 expression was increased along with the radiation exposure time and the final stable level was 8 times of the initial level. Knockdown of LINC01094 resulted in enhanced radiosensitivity of ccRCC cells. Mechanically, LINC01094 was a ceRNA of CHEK2 by sponging miR-577. Also, the enhancement of LINC01094 on ccRCC radioresistance was mediated by CHEK2-stabilized FOXM1 protein. CONCLUSION: LINC01094 facilitates ccRCC radioresistance by targeting miR-577/CHEK2/FOXM1 axis, blazing a new trail for overcoming radioresistance in ccRCC.

12.
J Clin Lab Anal ; 34(5): e23193, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31901150

RESUMO

BACKGROUND: Nucleolar and spindle-associated protein 1 (NUSAP1) has been identified to be strongly implicated in the carcinogenesis of cervical carcinoma, breast cancer, and liver cancer, and shows a high expression level in bladder cancer, indicating that NUSAP1 might be a potent target for cancer treatment. Using bioinformatics methods, we found that NUSAP1 was a putative target of miR-769-5p. Here, we aimed to explore whether miR-769-5p is involved in bladder cancer progression via targeting NUSAP1. METHODS: MiR-769-5p expression patterns in bladder cancer tissues and cells were detected by RT-PCR. Kaplan-Meier was used to determine the clinical effects of miR-769-5p expression levels on the overall survival of bladder cancer patients. Bioinformatics methods were used to predict the binding sites between miR-769-5p and NUSAP1, which was verified by the luciferase gene reporter assay. CCK-8, flow cytometry, wound healing and transwell chamber experiments were performed to test cell growth, apoptosis, migration and invasion capacities. RESULTS: miR-769-5p was lowly expressed in bladder cancer tissues and cells, which was closely associated with poor prognosis. Overexpression of miR-769-5p induced significant repressions in cell growth, migration, and invasion and caused an obvious increase in cell apoptosis, whereas these tendencies were reversed when NUSAP1 was upregulated. CONCLUSION: This study demonstrates that miR-769-5p functions as a tumor suppressor in bladder cancer via targeting NUSAP1.


Assuntos
MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/genética , Neoplasias da Bexiga Urinária/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Estimativa de Kaplan-Meier , Prognóstico , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/mortalidade
13.
Angew Chem Int Ed Engl ; 59(52): 23521-23526, 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-32909312

RESUMO

Selective hydrogenation of C=O against the conjugated C=C in cinnamaldehyde (CAL) is indispensable to produce cinnamyl alcohol (COL). Nonetheless, it is challenged by the low selectivity and the need to use organic solvents. Herein, for the first time, we report the use of Fe-Co alloy nanoparticles (NPs) on N-doped carbon support as a selective hydrogenation catalyst to efficiently convert CAL to COL. The resultant catalyst with the optimized Fe/Co ratio of 0.5 can achieve an exceptional COL selectivity of 91.7 % at a CAL conversion of 95.1 % in pure water medium under mild reaction conditions, ranking it the best performed catalyst reported to date. The experimental results confirm that the COL selectivity and CAL conversion efficiency are, respectively promoted by the presence of Fe and Co, while the synergism of the alloyed Fe-Co is the key to concurrently achieve high COL selectivity and CAL conversion efficiency.

14.
Angew Chem Int Ed Engl ; 59(32): 13423-13429, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32367577

RESUMO

Single-atom catalysts have demonstrated their superiority over other types of catalysts for various reactions. However, the reported nitrogen reduction reaction single-atom electrocatalysts for the nitrogen reduction reaction exclusively utilize metal-nitrogen or metal-carbon coordination configurations as catalytic active sites. Here, we report a Fe single-atom electrocatalyst supported on low-cost, nitrogen-free lignocellulose-derived carbon. The extended X-ray absorption fine structure spectra confirm that Fe atoms are anchored to the support via the Fe-(O-C2 )4 coordination configuration. Density functional theory calculations identify Fe-(O-C2 )4 as the active site for the nitrogen reduction reaction. An electrode consisting of the electrocatalyst loaded on carbon cloth can afford a NH3 yield rate and faradaic efficiency of 32.1 µg h-1 mgcat. -1 (5350 µg h-1 mgFe -1 ) and 29.3 %, respectively. An exceptional NH3 yield rate of 307.7 µg h-1 mgcat. -1 (51 283 µg h-1 mgFe -1 ) with a near record faradaic efficiency of 51.0 % can be achieved with the electrocatalyst immobilized on a glassy carbon electrode.

15.
Mol Cancer ; 18(1): 81, 2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-30953521

RESUMO

BACKGROUND: The aberrant expression of long noncoding RNAs (lncRNAs) has recently emerged as key molecules in human cancers; however, whether lncRNAs are implicated in the progression of clear cell renal cell carcinoma (ccRCC) remains unclear. METHODS: Candidate lncRNAs were selected using microarray analysis and quantitative real-time PCR (qRT-PCR) was performed to detect lncRNAs expression in human ccRCC tissues. Overexpression and knocking down experiments in vivo and in vitro were performed to uncover the biological roles of lncRNA-URRCC on ccRCC cell proliferation and invasion. Microarray, chromatin immunoprecipitation, Luciferase reporter assay and western blot were constructed to investigate the molecular mechanisms underlying the functions of lncRNA-URRCC. RESULTS: The microarray analysis and qRT-PCR identified a new lncRNA, URRCC, whose expression is upregulated in RCC samples and associated with poor prognosis, leading to promote ccRCC cell proliferation and invasion. Mechanistically, URRCC enhances the expression of EGFL7 via mediating histone H3 acetylation of EGFL7 promoter, activation of P-AKT signaling, and suppressing P-AKT downstream gene, FOXO3. In return, FOXO3 could inhibit the transcription of URRCC via binding to the special region on the promoter of URRCC. CONCLUSIONS: Our data suggests that targeting this newly identified feed-back loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling may enhance the efficacy of existing therapy and potentially imparts a new avenue to develop more potent therapeutic approaches to suppress RCC progression.


Assuntos
Carcinoma de Células Renais/patologia , Neoplasias Renais/patologia , RNA Longo não Codificante/genética , Transdução de Sinais , Animais , Proteínas de Ligação ao Cálcio , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Família de Proteínas EGF , Fatores de Crescimento Endotelial/metabolismo , Proteína Forkhead Box O3/metabolismo , Perfilação da Expressão Gênica , Humanos , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Camundongos , Metástase Neoplásica , Estadiamento de Neoplasias , Transplante de Neoplasias , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regulação para Cima
16.
Chemistry ; 25(23): 5904-5911, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30767346

RESUMO

Electrosynthesis of NH3 through the N2 reduction reaction (NRR) under ambient conditions is regarded as promising technology to replace the industrial energy- and capital-intensive Haber-Bosch process. Herein, a room-temperature spontaneous redox approach to fabricate a core-shell-structured Au@CeO2 composite, with Au nanoparticle sizes below about 10 nm and a loading amount of 3.6 wt %, is reported for the NRR. The results demonstrate that as-synthesized Au@CeO2 possesses a surface area of 40.7 m2 g-1 and a porous structure. As an electrocatalyst, it exhibits high NRR activity, with an NH3 yield rate of 28.2 µg h-1 cm-2 (10.6 µg h-1 mg-1 cat. , 293.8 µg h-1 mg-1 Au ) and a faradaic efficiency of 9.50 % at -0.4 V versus a reversible hydrogen electrode in 0.01 m H2 SO4 electrolyte. The characterization results reveal the presence of rich oxygen vacancies in the CeO2 nanoparticle shell of Au@CeO2 ; these are favorable for N2 adsorption and activation for the NRR. This has been further verified by theoretical calculations. The abundant oxygen vacancies in the CeO2 nanoparticle shell, combined with the Au nanoparticle core of Au@CeO2 , are electrocatalytically active sites for the NRR, and thus, synergistically enhance the conversion of N2 into NH3 .

17.
Phys Chem Chem Phys ; 21(11): 5950-5955, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30815666

RESUMO

It is highly attractive but challenging to develop earth-abundant electrocatalysts for nitrogen (N2) fixation. Here, by using density functional theory (DFT), we systematically investigate various single transition metal atom (Ti, V, Cr, Mn, Fe, Co, Ni, Ru, Rh and Pd) modified MoP surfaces as potential N2 reduction electrocatalysts for ammonia (NH3) synthesis. Through comparison of the stabilities of metal atom modified MoP, the adsorption energies and the bond lengths of N2 on different atom modified MoP, we select Mn and V as two candidates and study in detail the possible N2 reduction reaction (NRR) pathways for Mn-MoP and V-MoP. Our results revealed that Mn-MoP and V-MoP exhibit energy change values of 0.95 eV and 0.65 eV, respectively, with the first hydrogenation step being the potential-limiting step. Mn-MoP can efficiently suppress *H adsorption and reduce the competition of the hygrogen evolution reaction (HER) with the NRR; whereas, V-MoP cannot. Therefore, Mn-MoP is a better catalyst to realize the nitrogen reduction reaction. Overall, this work takes one step toward the NRR possibility of transition metal phosphides and provides some important insights and guidance to experiments.

18.
Angew Chem Int Ed Engl ; 58(46): 16644-16650, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31497911

RESUMO

As a metal-free nitrogen reduction reaction (NRR) photocatalyst, g-C3 N4 is available from a scalable synthesis at low cost. Importantly, it can be readily functionalized to enhance photocatalytic activities. However, the use of g-C3 N4 -based photocatalysts for the NRR has been questioned because of the elusive mechanism and the involvement of N defects. This work reports the synthesis of a g-C3 N4 photocatalyst modified with cyano groups and intercalated K+ (mCNN), possessing extended visible-light harvesting capacity and superior photocatalytic NRR activity (NH3 yield: 3.42 mmol g-1 h-1 ). Experimental and theoretical studies suggest that the -C≡N in mCNN can be regenerated through a pathway analogous to Mars van Krevelen process with the aid of the intercalated K+ . The results confirm that the regeneration of the cyano group not only enhances photocatalytic activity and sustains the catalytic cycle, but also stabilizes the photocatalyst.

19.
Small ; 14(36): e1801953, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30058300

RESUMO

Highly dispersed copper nanoparticles (Cu NPs) supported on activated carbon (AC) are effectively synthesized by one-pot carbothermal method at temperature range of 400-700 °C. The X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis reveal that Cu NPs with diameters of 20-30 nm are evenly anchored in carbon matrix. The 15 wt%-Cu/AC-600 catalyst (derived at 600 °C) exhibits best bifunctional catalysis of aqueous-phase hydrodeoxygenation (HDO) and organic-phase transfer-hydrogenation reaction (THR) to selectively transform vanillin to 2-methoxy-4-methylphenol (MMP). In HDO of vanillin, the as-prepared catalyst achieves a 99.9% vanillin conversion and 93.2% MMP selectivity under 120 °C, 2.0 MPa H2 within 5 h. Meanwhile, near-quantitative vanillin conversion and 99.1% MMP selectivity are also obtained under 180 °C within 5 h in THR of vanillin by using 2-propanol as hydrogen donor. The transforming pathways of vanillin are also proposed: vanillin is transformed into MMP via intermediate of 4-hydroxymethyl-2-methoxyphenol in HDO case and by direct hydrogenolysis of vanillin in THR course. More importantly, the activity and the selectivity do not change after 5 cycles, indicating the catalyst has excellent stability. The Cu-based catalyst is relatively cheap and preparation method is facile, green, and easy scale-up, thus achieving a low-cost transformation of biomass to bio-oils and chemicals.

20.
BMC Urol ; 18(1): 79, 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30200918

RESUMO

BACKGROUND: BRAF-activated long non-coding RNA (BANCR) has been associated with various types of cancer. Nevertheless, the role of BANCR in clear cell renal cell carcinoma (ccRCC) is still not fully understood. This study aims to investigate the relationship between ccRCC and BANCR. METHODS: Expression of BANCR in TCGA renal cancer data sets was analyzed. The expression pattern of BANCR in Immortalized normal human proximal tubule epithelial cell line HK-2 and ccRCC cell lines (ACHN, CAKI-1, A498 and 786-O) was detected by real-time quantitative RT-PCR (qRT-PCR). ccRCC tissues with adjacent normal renal tissues diagnosed by pathological methods from 62 patients were used to detect the expression of BANCR, and its correlation with prognosis of ccRCC patients was assessed by Kaplan-Meier method. The LV-BANCR vector was used to examine the influence of BANCR on the proliferation, migration, invasion, apoptosis and cell cycle distribution of ccRCC cells in vitro. RESULTS: BANCR was downregulated in renal cancer according to TCGA data sets. Compared with adjacent normal renal tissues and normal human proximal tubule epithelial cell line HK-2, BANCR expression was significantly decreased in ccRCC tissues and ccRCC cell lines, and its low expression was associated with poor prognosis. Moreover, in the condition of BANCR overexpression by LV-BANCR vector, the proliferation, migration, invasion capacity of ccRCC cells was inhibited, while the apoptosis was increased and the G1 cell cycle arrest was induced in vitro. CONCLUSIONS: BANCR is downregulated in ccRCC tissues and cell lines, and is associated with ccRCC progression. Thus, BANCR may represent a novel prognostic biomarker and a potential therapeutic target for ccRCC patients.


Assuntos
Carcinoma de Células Renais/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Renais/metabolismo , Proteínas Proto-Oncogênicas B-raf/metabolismo , RNA Longo não Codificante/metabolismo , Biomarcadores Tumorais , Carcinoma de Células Renais/genética , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Humanos , Estimativa de Kaplan-Meier , Rim/metabolismo , Neoplasias Renais/genética , Prognóstico , Proteínas Proto-Oncogênicas B-raf/genética
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