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1.
Small ; : e2404438, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39101630

RESUMO

Hematite (α-Fe2O3) has become a research hotspot in the field of photoelectrochemical water splitting (PEC-WS), but the low photogenerated carrier separation efficiency limits further application. The electronic structure regulation, such as element doping and organic functional groups with different electrical properties, is applied to alleviate the problems of poor electrical conductivity, interface defects, and band mismatch. Herein, α-Fe2O3 photoanodes are modified to regulate their electric structures and improve photogenerated carrier transport by the bimetallic metal-organic frameworks (MOFs), which are constructed with Fe/Ni and terephthalate (BDC) with 2-substitution of different organic functional groups (─H, ─Br, ─NO2 and ─NH2). The α-Fe2O3 photoanode loaded with FeNi-NH2BDC MOF catalyst exhibits the optimal photocurrent density (2 mA cm-2) at 1.23 VRHE, which is 2.33 times that of the pure α-Fe2O3 photoanode. The detailed PEC analyses demonstrate that the bimetallic synergistic effect between Fe and Ni can improve the conductivity and inhibit the photogenerated carrier recombination of α-Fe2O3 photoanodes. The ─NH2 group as an electron-donor group can effectively regulate the electron distribution and band structure of α-Fe2O3 photoanodes to prolong the lifetime of photogenerated holes, which facilitates photogenerated carrier transport and further enhances the PEC-WS performance of α-Fe2O3 photoanode.

2.
Inorg Chem ; 62(46): 18809-18813, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37943673

RESUMO

The design of a highly and photomodulated proton conductor is important for advanced potential applications in chemical sensors and bioionic functions. In this work, a metal-organic framework (MOF; Gd-NO2) with high proton conductivity is synthesized with a photosensitive ligand of 5-nitroisophthalic acid (BDC-NO2), and it provides remote-control photomodulated proton-conducting behavior. The proton conduction of Gd-NO2 reaches 3.66 × 10-2 S cm-1 at 98% relative humidity (RH) and 25 °C, while it decreases by ∼400 times after irradiation with a 355 nm laser. The newly generated and disappearing FT-IR characteristic peaks reveal that this photomodulated process is realized by the photoinduced transformation from BDC-NO2 to 5-nitroso-isophthalic acid (BDC-NO). According to density functional theory, the smaller electronegativity of the -NO group, the longer distance of the hydrogen bond between BDC-NO and H2O molecules, and the lower water adsorption energy of BDC-NO indicate that the irradiated sample possesses a poorer hydrophilicity and has difficulty forming rich hydrogen-bonded networks, which results in the remarkable decrease of proton conductivity.

3.
Int Orthop ; 47(3): 735-743, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36645475

RESUMO

PURPOSE: The purpose was to investigate the effect of different degrees of valgus deformity correction on patellar position and clinical outcome in patients with valgus knees after total knee arthroplasty (TKA). METHODS: We retrospectively analyzed and followed 118 patients with valgus knees. Based on the post-operative hip-knee-ankle (HKA), patients were divided into three groups: neutral (±3°), mild (3-6°), and severe (> 6°). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion (ROM), and Knee Society Score (KSS) were used to evaluate post-operative clinical efficacy. Also, the patellar tilt angle (ε-angle), congruence angle (θ-angle), and Insall-Salvati index (ISI) were used to represent the patellar position. Post-operative observation indicators included HKA, angle of the femur (α-angle), tibial angle (ß-angle), femoral component flexion angle (γ-angle), and tibial component posterior slope angle (δ-angle). RESULTS: All patients showed significant improvements in HKA, ROM, WOMAC, and KSS after operation (P < 0.001). Regarding patellar position, the ISI values decreased to varying degrees (P < 0.05). The patellar tilt angle was significantly increased in the severe valgus group compared to that in the mild valgus and neutral groups (P < 0.001). Univariate analysis showed that the degree of post-operative residual valgus was significantly affected by WOMAC, KSS, α-, ε-, and θ-angles. CONCLUSION: Minor valgus undercorrection did not affect the short-term outcome after TKA; however, when the residual valgus angle was > 6°, the post-operative scores were significantly reduced. Inadequate valgus correction does not result in significant changes in patellar height but may increase the risk of poor patellar tracking.


Assuntos
Artroplastia do Joelho , Osteoartrite do Joelho , Humanos , Artroplastia do Joelho/efeitos adversos , Estudos Retrospectivos , Osteoartrite do Joelho/cirurgia , Articulação do Joelho/cirurgia , Joelho/cirurgia
4.
Int J Mol Sci ; 24(16)2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37628905

RESUMO

This present study was conducted to provide evidence and an explanation for the apoptosis that occurs in the marine rotifer Brachionus plicatilis when facing 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) stress. Metabolomics analysis showed that aminoacyl-tRNA biosynthesis, valine, leucine and isoleucine biosynthesis, and arginine biosynthesis were the top three sensitive pathways to BDE-47 exposure, which resulted in the reduction in the amino acid pool level. Pyrimidine metabolism and purine metabolism pathways were also significantly influenced, and the purine and pyrimidine content were obviously reduced in the low (0.02 mg/L) and middle (0.1 mg/L) concentration groups while increased in the high (0.5 mg/L) concentration group, evidencing the disorder of nucleotide synthesis and decomposition in B. plicatilis. The biochemical detection of the key enzymes in purine metabolism and pyrimidine metabolism showed the downregulation of Glutamine Synthetase (GS) protein expression and the elevation of Xanthine Oxidase (XOD) activity, which suggested the impaired DNA repair and ROS overproduction. The content of DNA damage biomarker (8-OHdG) increased in treatment groups, and the p53 signaling pathway was found to be activated, as indicated by the elevation of the p53 protein expression and Bax/Bcl-2 ratio. The ROS scavenger (N-acetyl-L-cysteine, NAC) addition effectively alleviated not only ROS overproduction but also DNA damage as well as the activation of apoptosis. The combined results backed up the speculation that purine metabolism and pyrimidine metabolism alteration play a pivotal role in BDE-47-induced ROS overproduction and DNA damage, and the consequent activation of the p53 signaling pathway led to the observed apoptosis in B. plicatilis.


Assuntos
Rotíferos , Proteína Supressora de Tumor p53 , Animais , Espécies Reativas de Oxigênio , Éteres Difenil Halogenados , Apoptose
5.
Molecules ; 28(5)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36903282

RESUMO

Polybrominated diphenyl ethers (PBDEs) are classic and emerging pollutants that are potentially harmful to the human immune system. Research on their immunotoxicity and mechanisms suggests that they play an important role in the resulting pernicious effects of PBDEs. 2,2',4,4'-Tetrabrominated biphenyl ether (BDE-47) is the most biotoxic PBDE congener, and, in this study, we evaluated its toxicity toward RAW264.7 cells of mouse macrophages. The results show that exposure to BDE-47 led to a significant decrease in cell viability and a prominent increase in apoptosis. A decrease in mitochondrial membrane potential (MMP) and an increase in cytochrome C release and caspase cascade activation thus demonstrate that cell apoptosis induced by BDE-47 occurs via the mitochondrial pathway. In addition, BDE-47 inhibits phagocytosis in RAW264.7 cells, changes the related immune factor index, and causes immune function damage. Furthermore, we discovered a significant increase in the level of cellular reactive oxygen species (ROS), and the regulation of genes linked to oxidative stress was also demonstrated using transcriptome sequencing. The degree of apoptosis and immune function impairment caused by BDE-47 could be reversed after treatment with the antioxidant NAC and, conversely, exacerbated by treatment with the ROS-inducer BSO. These findings indicate that oxidative damage caused by BDE-47 is a critical event that leads to mitochondrial apoptosis in RAW264.7 macrophages, ultimately resulting in the suppression of immune function.


Assuntos
Éteres Difenil Halogenados , Mitocôndrias , Camundongos , Animais , Humanos , Espécies Reativas de Oxigênio/metabolismo , Éteres Difenil Halogenados/farmacologia , Mitocôndrias/metabolismo , Macrófagos/metabolismo
6.
Inflamm Res ; 71(2): 191-204, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35028708

RESUMO

OBJECTIVE: Inflammation is central to the development and progression of diabetic nephropathy (DN). Although the exact mechanisms of inflammation in the kidney have not been well elucidated, pyrin domain containing 3 (NLRP3) inflammasome activation is involved in the onset and progression of DN. Here, we investigated the underlying regulatory mechanisms of hyperglycaemia-induced NLRP3 inflammasome activation in the kidney. METHODS: HEK293T cells received high glucose, and the cell proliferation and apoptosis were detected. Biochemical indicators in db/db mice were tested by kits, and the morphological changes in the kidney were observed using staining methods and transmission electron microscopy. The interaction of Ras-related C3 botulinum toxin substrate 1 (RAC1) and NLRP3 inflammasome in cells and in mice was assessed by co-immunoprecipitation (Co-IP) and immunofluorescence. Expression of all proteins was examined by western blotting and immunohistochemistry. In additional, the directly combination of RAC1 and NLRP3 was evaluated by GST Pulldown. RESULTS: High-glucose and hyperglycaemia conditions resulted in Ras-related C3 botulinum toxin substrate 1 (RAC1) and NLRP3 inflammasome interactions in cells and in mice. Additionally, RAC1 promoted NLRP3 inflammasome activation and then induced cell damage, and morphological and functional abnormalities in the kidney. We also observed that RAC1 activates the NLRP3 inflammasome by directly binding to NLRP3. CONCLUSION: In the present study, we confirmed that RAC1 binding to NLRP3 is sufficient to activate the NLRP3 inflammasome in the kidney and accelerate DN pathological processes. These results elucidate the upstream cellular and molecular mechanisms of NLRP3 inflammasome activation and provide new therapeutic strategies for the treatment of DN.


Assuntos
Nefropatias Diabéticas/etiologia , Inflamassomos/fisiologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/fisiologia , Proteínas rac1 de Ligação ao GTP/fisiologia , Animais , Caspase 1/fisiologia , Células HEK293 , Humanos , Hiperglicemia/complicações , Interleucina-1beta/fisiologia , Rim/patologia , Masculino , Camundongos , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores
7.
Inorg Chem ; 61(23): 8685-8693, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35639458

RESUMO

Titanium oxo clusters (TOCs) with accurate molecular structures have potential applications in photocatalysis, such as photocatalytic degradation, hydrogen production, and water oxidation. The hydrolytic stability and light absorption ability of TOCs have important impacts on photocatalysis, where the selection of peripheral organic ligands plays a significant role. In this regard, salicylhydroxamic acid (abbreviated as H3L) attracts our attention, acting as a ligand for its multidentate and dye-functional features, which can increase the hydrolytic stability and broaden light absorption for TOCs. Herein, two TOCs were solvothermally synthesized and structurally characterized using H3L, formulated as [Ti8(µ2-O)2(µ3-O)2(OiPr)12(L)4]·2CH3CN (1) and [Ti16(µ2-O)10(µ3-O)4(PhCOO)14(L)6(HL)2]·4CH3CN·2iPrOH (2). Complex 2 was obtained by adding excessive benzoic acid over the reaction system of 1, resulting in enhanced hydrolytic stability via the replacement of all alkoxy ligands by multidentate ligands for protection. Interestingly, for the first time, the "three-in-one" structural building mode with {Ti6} + {Ti4} + {Ti6} by the common subunits in 2 was observed among all reported TOCs. Moreover, complex 2 can strongly absorb visible light reaching up to 700 nm and exhibit obvious activity for the photodegradation of methyl orange.


Assuntos
Benzoatos , Titânio , Ligantes , Salicilamidas , Titânio/química
8.
Phys Chem Chem Phys ; 22(14): 7306-7313, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32211650

RESUMO

A semiconductor underlayer(s) has been extensively used to improve the performance of photoelectrochemical (PEC) cells. Unfortunately, in many cases, the incorporation of underlayers leads to degraded system performances. A comprehensive study on the functions and manipulations of underlayers is therefore of high significance for achieving high-performance PEC cells. This study indicates that Sn-doped hematite photoanodes decorated with various underlayer materials show substantially distinguished photocurrent responses, leading to qualitatively different PEC cells. With an optimized TiO2 (ITO, Al2O3) underlayer, the photocurrent density at 1.23 V versus RHE can be enhanced from 0.25 to 0.71 (0.59, 0.42) mA cm-2, while it is decreased to 0.14 mA cm-2 by using NiO. Our further analysis reveals that the performance differences come mainly from the distinguished bulk and surface carrier recombination effects, i.e., (1) metal doping (i.e., Ti4+, In3+ and Al3+) from the underlayers improves the conductivity of hematite film and thus reduces the bulk recombination; (2) the underlayers of TiO2, ITO and Al2O3 can effectively suppress the carrier recombination at the bottom/top surfaces of the hematite layer, while the NiO underlayer leads to a higher surface recombination. Our work provides a basis for selecting an underlayer and a general guideline for the interface engineering for high performance photoelectrodes.

9.
Org Biomol Chem ; 17(5): 1191-1201, 2019 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-30648165

RESUMO

Here we describe the Cp*Rh(iii)-catalyzed cascade arylfluorination reactions of α-diazoketoesters with arylboronic acids and N-fluorobenzenesulfonimide for one-pot C(sp3)-C(aryl) and C(sp3)-F bond formation. The arylfluorination reaction can be accomplished with remarkable chemo- and regioselectivity. Our mechanistic investigation showed that the Rh-catalyzed arylfluorination of diazoacetates occurred by (1) transmetalation of arylboronic acids to form an arylrhodium(iii) complex, (2) coupling of diazomalonates with the arylrhodium(iii) complex to form carbene-rhodium, (3) migratory carbene insertion to form a diketonato-rhodium(iii) complex - probably via rearrangement of the putative σ-alkylrhodium(iii) complex, and (4) electrophilic fluorination of the diketonato-rhodium to form the α-aryl-α-fluoromalonates.

10.
Org Biomol Chem ; 14(28): 6821-5, 2016 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-27339710

RESUMO

A [Cp*Rh(iii)]-catalyzed electrophilic amination of arylboronic acids with diethyl azodicarboxylate (DEAD) was developed, and arylhydrazides were produced in excellent yields and selectivity. The analogous amination with the arylazocarboxylates afforded the corresponding N,N-diarylhydrazides. The electrophilic amination of arylboronic acids with azocarboxylates proceeds readily under mild conditions with excellent functional group tolerance. Up to 99% yields were obtained. Preliminary mechanistic studies revealed that prior formation of an arylrhodium(iii) intermediate for the azo coupling reaction can be ruled out.

11.
J Org Chem ; 80(14): 6968-75, 2015 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-26105579

RESUMO

A series of novel chiral phosphoramidite ligands based on chiral-bridged biphenyl backbones have been prepared conveniently and characterized. The ligands complexed with [IrCodCl]2 provided the first iridium catalyst system for the asymmetric addition of arylboronic acids to N-protected isatins with high efficiency. When performed in THF/H2O at 80 °C with 2 equiv of the arylboronic acids, the transformations acquired good to excellent results (up to 98% yield and 95% ee).


Assuntos
Ácidos Borônicos/química , Isatina/química , Compostos Organofosforados/síntese química , Catálise , Hidrogenação , Irídio , Ligantes , Estrutura Molecular , Compostos Organofosforados/química
12.
Chemistry ; 20(15): 4474-80, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24596116

RESUMO

A Rh(III) -catalyzed direct ortho-CH amidation/amination of benzoic acids with N-chlorocarbamates/N-chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent ortho-selectivity and functional-group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO2 Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N-chlorocarbamate afforded an amido-rhodium(III) complex, which was isolated and structurally characterized by X-ray crystallography. This finding confirmed that the CN bond formation results from the cross-coupling of N-chlorocarbamate with the aryl-rhodium(III) complex. Yet, the mechanistic details regarding the CN bond formation remain unclear; pathways involving 1,2-aryl migration and rhodium(V)- nitrene are plausible.

13.
Org Biomol Chem ; 12(24): 4112-6, 2014 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-24788558

RESUMO

A Rh(III)-catalyzed oxidative [4 + 1] cycloaddition of benzohydroxamic acids and α-diazoesters is achieved to afford benzolactams in up to 93% yields. With the N-OAc amido moiety as a directing group, the ortho-C-H is selectively functionalized and the catalytic reaction exhibits excellent tolerance to different functional substituents. A notable rhodacyclic complex is isolated and structurally characterized, suggesting that C-H/N-H cyclometallation is a key step in the catalytic cycle.

14.
Antioxidants (Basel) ; 13(4)2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38671912

RESUMO

The ionic properties of strontium (Sr), a significant artificial radionuclide in the marine environment, were estimated using a stable nuclide-substituting experimental system under controlled laboratory conditions. The bio-accumulation of Sr and its impacts, as well as any possible hidden mechanisms, were evaluated based on the physiological alterations of the sentinel blue mussel Mytilus edulis. The mussels were exposed to a series of stress-inducing concentrations, with the highest solubility being 0.2 g/L. No acute lethality was observed during the experiment, but sublethal damage was evident. Sr accumulated in a tissue-specific way, and hemolymph was the target, with the highest accumulating concentration being 64.46 µg/g wet weight (ww). At the molecular level, increases in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and changes in ROS components (H2O2, O2-, and -OH) and antioxidant system activity indicated that the redox equilibrium state in hemocytes was disturbed. Furthermore, the rise in the hemocyte micronucleus (MN) rate (4‱ in the high-concentration group) implied DNA damage. At the cellular level, the structures of hemocytes were damaged, especially with respect to lysosomes, which play a crucial role in phagocytosis. Lysosomal membrane stability (LMS) was also affected, and both acid phosphatase (ACP) and alkaline phosphatase (AKP) activities were reduced, resulting in a significant decline in phagocytosis. The hemolymph population structure at the organ level was disturbed, with large changes in hemocyte number and mortality rate, along with changes in component ratios. These toxic effects were evaluated by employing the adverse outcome pathway (AOP) framework. The results suggested that the disruption of intracellular redox homeostasis is a possible explanation for Sr-induced toxicity in M. edulis.

15.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 35(5): 533-537, 2023 May.
Artigo em Zh | MEDLINE | ID: mdl-37308237

RESUMO

OBJECTIVE: To establish a new emergency dynamic score (EDS) method based on modified early warning score (MEWS) combined with clinical symptoms, rapidly available examination results and bedside examination data in the emergency department, and to observe its applicability and feasibility in the clinical application of emergency department. METHODS: A total of 500 patients admitted to the department of emergency of Xing'an County People's Hospital from July 2021 to April 2022 were selected as research objects. After admission, EDS and MEWS scores were performed first, and then acute physiology and chronic health evaluation II (APACHE II) was performed retrospectively, and the prognosis of patients was followed up. The difference of short-term mortality in patients with different score segments of EDS, MEWS and APACHE II were compared. Receiver operator characteristic curve (ROC curve) was drawn to evaluate the prognostic value of various scoring methods in critically ill patients. RESULTS: The mortality of patients in different score groups of each scoring method increased with the increase of the score value [The mortality of 0-1, 2-3, 4-5, 6-7 and ≥ 8 of MEWS were 1.9% (3/159), 2.9% (6/208), 12.4% (11/89), 29.0% (9/31) and 61.5% (8/13), respectively. The mortality of EDS stage 1 weighted MEWS score 0-3, 4-6, 7-9, 10-12 and ≥ 13 were 0 (0/49), 3.2% (8/247), 6.6% (10/152), 31.9% (15/47) and 80.0% (4/5), respectively. The mortality of EDS stage 2 clinical symptom score 0-4, 5-9, 10-14, 15-19, ≥ 20 were 0 (0/13), 0.4% (1/235), 3.6% (6/165), 26.2% (17/65), 59.1% (13/22), respectively. The mortality of EDS stage 3 rapid test data score 0-6, 7-12, 13-18, 19-24 and ≥ 25 were 0 (0/16), 0.6% (1/159), 4.6% (6/131), 13.7% (7/51) and 65.0% (13/20), respectively. The mortality of patients with APACHE II score 0-6, 7-12, 13-18, 19-24 and ≥ 25 were 1.9% (1/53), 0.4% (1/277), 4.6% (5/108), 34.2% (13/38) and 70.8% (17/24), respectively, all P < 0.01]. When the MEWS score was more than 4, the specificity was 87.0%, the sensitivity was 67.6%, and the maximum Youden index was 0.546, which was the best cut-off point. When the weighted MEWS score of EDS in the first stage was greater than 7, the specificity of predicting the prognosis of patients was 76.2%, the sensitivity was 70.3%, and the maximum Youden index was 0.465, which was the best cut-off point. When clinical symptom score of EDS in the second stage was more than 14, the specificity and sensitivity of predicting the prognosis of patients were 87.7% and 81.1%, respectively, and the maximum Youden index was 0.688, which was the best cut-off point. When the third stage rapid test of EDS reached 15 points, the specificity of predicting the prognosis of patients was 70.9%, and the sensitivity was 96.3%, and the maximum Youden index was 0.672, which was the best cut-off point. When APACHE II score was higher than 16, the specificity was 87.9%, the sensitivity was 86.5%, and the maximum Youden index was 0.743, which was the best cut-off point. ROC curve analysis showed that: EDS score in the stage 1, 2 and 3, MEWS score and APACHE II score can predict the short-term mortality risk of critically ill patients. The area under the ROC curve (AUC) and 95% confidence interval (95%CI) were 0.815 (0.726-0.905), 0.913 (0.867-0.959), 0.911 (0.860-0.962), 0.844 (0.755-0.933) and 0.910 (0.833-0.987), all P < 0.01. In terms of the differential ability to predict the risk of death in the short-term, the AUC in the second and third stages of EDS were highly close to APACHE II score (0.913, 0.911 vs. 0.910), and significantly higher than MEWS score (0.913, 0.911 vs. 0.844, both P < 0.05). CONCLUSIONS: EDS method can dynamically evaluate emergency patients in stages, and has the characteristics of fast, simple, easy to obtain test and inspection data, which can facilitate emergency doctors to evaluate emergency patients objectively and quickly. It has strong ability to predict the prognosis of emergency patients, and is worth popularizing in emergency departments of primary hospitals.


Assuntos
Estado Terminal , Projetos de Pesquisa , Humanos , Estudos Retrospectivos , Hospitais , Serviço Hospitalar de Emergência
16.
Dalton Trans ; 52(32): 11203-11212, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37522640

RESUMO

As one of the most popular photoanode materials, hematite (α-Fe2O3) has obvious advantages in the field of photoelectrochemical water splitting (PEC-WS). However, it is difficult to achieve excellent PEC-WS performance without loading a cocatalyst serving as an electron/hole collector to promote photogenerated carrier separation. In this work, FTO/Sn@α-Fe2O3 photoanodes are modified with ZnCo-ZIF and ZnCoOOH bimetallic catalysts to obtain FTO/Sn@α-Fe2O3/Zn0.5Co0.5-ZIF and FTO/Sn@α-Fe2O3/Zn0.46Co0.54OOH photoanodes. Their photocurrent densities reach 2.6 mA cm-2 and 2.3 mA cm-2 at 1.23 VRHE, respectively. The detailed mechanism studies demonstrate that both ZnCoOOH and ZnCo-ZIF can effectively decrease the transfer resistance, increase the Fe2+/Fe3+ ratio and reduce the charge recombination of the α-Fe2O3 film, which synergistically improves the PEC-WS performance. Compared with ZnCoOOH, the ZnCo-ZIF exhibits better photogenerated carrier transfer efficiency and catalytic performance, which mainly can be attributed to the improved binding energy between the ZnCo-ZIF catalyst and the α-Fe2O3 film. This work provides a simple and feasible strategy for constructing bimetallic catalysts and deepens the understanding of different types of bimetallic catalysts for high-performance PEC-WS systems.

17.
Dalton Trans ; 52(35): 12308-12317, 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37591825

RESUMO

Surface catalyst engineering can effectively improve the photoelectrochemical water splitting (PEC-WS) performance of semiconductor photoelectrodes. In situ surface functional treatments can effectively reduce interface defects and improve photogenerated carrier transport. In this study, FTO/Sn@α-Fe2O3/FeOOH photoanodes were modified with in situ sulfide/nitride/phosphide treatments to improve their PEC-WS performance. Compared with the pure α-Fe2O3 photoanode, the photocurrent densities of FTO/Sn@α-Fe2O3/FeOOH photoanodes after sulfide/nitride/phosphide treatments increased from 0.88 to 3.38 mA cm-2 at 1.23 VRHE. The onset potential showed a cathode shift of 0.1 V. Photoelectrochemical analyses and theoretical calculation demonstrated that the surface engineering by sulfide/nitride/phosphide treatments can significantly reduce surface defects, enhance electrical conductivity and promote photogenerated carrier separation and transfer efficiency by regulating interface charge transfer, binding energy and internal electric field. The formation of an FeSx catalyst and N/P coordination complexes in the sulfide/nitride/phosphide processes on the surface of α-Fe2O3 photoanodes can effectively reduce photogenerated carrier recombination. This work provides experimental and theoretical support for surface structure design and improved photoelectric conversion performance of semiconductor photoelectrode materials.

18.
Sci Total Environ ; 885: 163766, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37146804

RESUMO

The energetic response of blue mussel Mytilus edulis when coping with tetrabromodiphenyl ether (BDE-47) exposure was evaluated from the perspective of alterations in energy supply mode, and the possible regulating mechanism was discussed based on a 21-day bioassay. The results showed that the energy supply mode changed with concentration: 0.1 µg/L BDE-47 decreased the activity of isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase and oxidative phosphorylation, suggesting inhibition of the tricarboxylic (TCA) acid cycle and aerobic respiration. The coincident increase in phosphofructokinase and the decrease in lactate dehydrogenase (LDH) indicated that glycolysis and anaerobic respiration were increased. When exposed to 1.0 µg/L BDE-47, M. edulis mainly utilized aerobic respiration, but lowered glucose metabolism as indicated by the decrease in glutamine and l-leucine was suggested to be involved in this process, which was differed from that in the control. The reoccurrence of IDH and SDH inhibition as well as LDH elevation indicated attenuation of aerobic and anaerobic respiration when the concentration increased to 10 µg/L, but severe protein damage was evidenced based on the elevation of amino acids and glutamine. Under the 0.1 µg/L BDE-47, activation of the AMPK-Hif-1a signaling pathway promoted the expression of glut1, which was the potential mechanism for the improvement of anaerobic respiration, and further activated glycolysis and anaerobic respiration. This study shows that the energy supply mode experienced a conversion from aerobic respiration under normal conditions to anaerobic mode in the low BDE-47 treatment and back to aerobic respiration with increasing BDE-47 concentrations, which may represent a potential mechanism for mussel physiological responses when faced with different levels of BDE-47 stress.


Assuntos
Mytilus edulis , Mytilus , Animais , Hemócitos , Glutamina , Éteres Difenil Halogenados/toxicidade
19.
J Am Chem Soc ; 134(33): 13565-8, 2012 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-22860697

RESUMO

A Rh-catalyzed intermolecular coupling of diazomalonates with arene C-H bonds is reported. The reaction is initiated by electrophilic C-H activation, which is followed by coupling of the arylrhodium(III) complex with the diazomalonate. In most cases, arenes with oximes, carboxylic acids, and amines as directing groups cross-couple with diazomalonates with excellent regioselectivities and functional group tolerance, and thus, this reaction offers a new route to α-aryl carbonyl compounds for specific applications.

20.
Inorg Chem ; 51(12): 6468-75, 2012 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-22670864

RESUMO

Ruthenium(II) terpyridine complexes containing the pyrrole-tagged 2,2'-dipyridylamine ligand PPP (where PPP stands for N-(3-bis(2-pyridyl)aminopropyl)pyrrole with the general formula [Ru(tpy)(PPP)X](n+) (1, X = Cl(-); 2, X = H(2)O; 3, X = CH(3)CN; tpy = 2,2':6',2"-terpyridine) have been synthesized and characterized by (1)H NMR, IR, UV-vis, mass spectrometry, and elemental analysis. 1 and 2 have been structurally characterized by X-ray crystallography. Both 1 and 2 were successfully immobilized onto glassy carbon electrode via anodic oxidation of the pyrrole moiety on the PPP ligand to give stable and highly electroactive polymer films. Cyclic voltammetric studies of 1 in acetonitrile revealed a Ru(III)/Ru(II) couple at 0.4 V vs Cp(2)Fe(+/0) initially, but another redox couple resulting from chloride substitution by acetonitrile developed at E(1/2) = 0.82 V upon repetitive potential scan. This ligand substitution was induced by the acidic local environment caused by the release of protons during pyrrole polymerization. The electropolymerization of 2 in aqueous medium allowed the observation of the formation of Ru(IV)═O species in polypyrrole film. As the film grew thicker, the size of the Ru(III)/(/)Ru(II) couple (E(1/2) = 0.8 V vs SCE at pH 1) of poly[Ru(tpy)(PPP)(OH(2))](n+) increased accordingly, whereas the growth of the Ru(IV)/Ru(III) couple (E(1/2) = 0.89 V vs SCE at pH 1) leveled off after the film had reached a certain thickness. The Pourbaix diagram of the E(1/2) of the Ru(III) /Ru(II) and Ru(IV)/Ru(III) couples vs pH of the electrolyte medium has been obtained. The resulting poly[Ru(tpy)(PPP)(OH(2))](n+) film is electrocatalytically active toward the oxidation of benzyl alcohol.


Assuntos
2,2'-Dipiridil/análogos & derivados , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Piridinas/química , Pirróis/química , Rutênio/química , 2,2'-Dipiridil/química , Cristalografia por Raios X , Eletroquímica , Ligantes , Modelos Moleculares , Estrutura Molecular
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