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1.
Small ; 20(29): e2311631, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38513241

RESUMO

Nanoparticles composed of high-entropy alloys (HEA NPs) exhibit remarkable performance in electrocatalytic processes such as hydrogen evolution and oxidations. In this study, two types of quinary HEA NPs of PtRhPdIrRu, are synthesized, featuring disordered and crystallized nanostructures, both with and without a boiling mixture. The disordered HEA NPs (d-HEA NPs) with a size of 3.5 nm is synthesized under intense boiling conditions, attributed to improved heat and mass transfer during reduction of precursors and particle growth. The disordered HEA NPs displayed an exceptionally high turnover frequency of 33.1 s-1 at an overpotential of 50 mV, surpassing commercial Pt NPs in acidic electrolytes by 5.4 times. Additionally, d-HEA NPs exhibited superior stability at a constant electrolyzing current of 50 mA cm-2 compared to commercial Pt NPs. When employed as the anodic catalyst in an H2-O2 fuel cell, d-HEA NPs demonstrated a remarkable high current power density of 15.3 kW per gram of noble metal. Consequently, these findings highlight the potential of d-HEA NPs in electrochemical applications involving hydrogen.

2.
Environ Res ; 252(Pt 2): 118890, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38615791

RESUMO

The human health risk assessment through the dermal exposure of metal (loid)s in dust from low latitude and high geological background plateau cities was largely unknown. In this study, the road dust samples were harvested from a typical low-latitude plateau provincial capital city Kunming, Southwest China. The total concentration and dermal bioaccessibility of heavy metal (loid)s in road dust were determined, and their health risks as well as cytotoxicity on human skin keratinocytes were also assessed. The average concentrations of As (28.5 mg/kg), Cd (2.65 mg/kg), Mn (671 mg/kg), and Zn (511 mg/kg) exceeded the soil background values. Arsenic had the highest bioaccessibility after 2 h (3.79%), 8 h (4.24%), and 24 h (16.6%) extraction. The dermal pathway when bioaccessibility is considered has a higher hazard quotient than the conventional method using total metal(loid)s in the dust. In addition, toxicological verification suggested that the dust extracts suppressed the cell viability, increased the reactive oxygen species (ROS) level and DNA damage, and eventually activated the mitochondria-mediated apoptosis pathway, evidenced by the upregulation of Caspase-3/9, Bax, and Bak-1. Cadmium was positively correlated with the mRNA expression of Bax. Taken together, our data indicated that both dermal bioaccessibility and cytotoxicity should be considered for accurate human skin health risk assessment of heavy metal(loid)s in road dust, which may provide new insight for accurate human health risk assessment and environmental management.


Assuntos
Poeira , Metais Pesados , Poeira/análise , Humanos , Medição de Risco , Metais Pesados/análise , Metais Pesados/toxicidade , China , Cidades , Exposição Ambiental , Queratinócitos/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/metabolismo , Monitoramento Ambiental/métodos
3.
Chaos ; 34(7)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38980383

RESUMO

Because of the manufacturing variations of circuit elements and the effects of parasitic parameters, the switching elements of parallel-connected modules cannot be synchronously switched. Consequently, the characteristics of these converters, which are multi-mode, high-order systems, cannot be comprehensively described using reduced-order models based on the symmetry of circuit topology and parameters. It is also difficult to fully describe the characteristics of these systems using discrete mapping models and averaged models. Therefore, we developed a smooth, sigmoid function-based continuous-time model for systems comprising parallel-connected buck converters with average current-sharing control. The proposed model provides a unified description of the continuous and discontinuous conduction modes of the system. The criteria for ensuring the stability of the system were derived based on the Floquet theory. The nonlinear dynamic behavior of the system and the effects of the key parameters on the stability of the system were investigated. The results showed that the system may undergo period doubling bifurcation, border collision bifurcation, and Neimark-Sacker bifurcation as the system parameters varied. The theoretical analysis and simulation results were verified experimentally. Our results provide a basis for the configuration of controller parameters.

4.
J Liposome Res ; : 1-13, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38563474

RESUMO

ABSTACTThe medicinal properties of genetic drugs are highly dependent on the design of delivery systems. Ionizable cationic lipids are considered core materials in delivery systems. However, there has not yet been a widespread consensus on the relationship between the wide diversity of lipid structure design and gene delivery efficiency. The aims of the research work were to synthesize ionizable cholesterol derivatives (iChol-lipids) and to evaluate their potential applications as gene delivery vector. A series of iChol-lipids with different head groups were synthesized with carbamate bond spacer. The chemical structures were characterized by 1H NMR, MS, melting range, and pKa. The interactions between iChol-lipids and MALAT1-siRNA were studied by molecular dynamics simulations and compared with market available DC-Chol, which revealed that hydrogen bonds, salt-bridge, and electrostatic interaction were probably involved. The self-assemble behaviors of these lipids were intensively investigated and evaluated by dynamic laser scattering in the presence of different helper lipids and PEGylated lipids. Their plasmid binding ability, transfection efficiency, hemolytic toxicity, and cytotoxicity were fully studied. IZ-Chol-LNPs was proved to be highly potential to effectively complex with DNA, and endosome escape mechanisms mediated by proton sponge effect was verified by pH-sensitive fluorescence probe BCFL.

5.
Environ Geochem Health ; 46(8): 286, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967819

RESUMO

The vacuum preloading coupling flocculation treatment is a widely employed method for reinforcing soils with high water content in practical construction. However, uneven distribution and accumulation of flocculants pose significant damage to the soil environment and result in uneven soil consolidation, leading to severe issues in subsequent soil development and exploitation. To address these concerns, an evolved leaching with vacuum method is developed for facilitating soil consolidation while preventing the accumulation of flocculant in the soil. In this study, five model tests are conducted in which FeCl3 is chosen as the typical flocculant to promote soil consolidation, and deionized water is used for leaching. The final discharged water, settlement, water content and penetration resistance of soil are obtained to evaluate the soil reinforcement effect, while the flocculant removal effect is evaluated by the Fe3+ content in the filtrate and soil. The comprehensive reinforcement and flocculant removal effect show that this method is extremely effective compared to traditional vacuum preloading. The two leaching is clarified as the best choice, resulting in a 22% decrease in the soil water content and a 25% in soil penetration resistance, meanwhile a 12.8% removal rate of the flocculant. The test results demonstrate that leaching with vacuum preloading can contribute to promoting soil consolidation and reducing the accumulation of flocculant in the soil, ensuring the safe and eco-friendly use of the soil for future applications. The conclusions obtained are of significant theoretical value and technical support for practical construction and sustainable development.


Assuntos
Floculação , Solo , Solo/química , Vácuo , Poluentes do Solo/química , Compostos Férricos/química , Cloretos/química
6.
J Liposome Res ; 33(4): 353-367, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36974836

RESUMO

tLyP-1 peptide is verified to recognize neuropilin (NRP) receptors overexpressed on the surface of both glioma cells and endothelial cells of angiogenic blood vessels. In the present study, tLyP-1 was conjugated with DSPE-PEG2000 to prepare tLyP-1-DSPE-PEG2000, which was further employed to prepare tLyP-1 functionalized nanoliposome (tLyP-1-Lip) to achieve enhancing target of glioblastoma. Process parameters were systematically studied to investigate the feasibility of tuning the internal water phase of nanoliposomes and encapsulating more Temozolomide (TMZ). The particle size, Zeta potential, and encapsulation efficiency of tLyP-1-Lip/TMZ were fully characterized in comparison with conventional nanoliposomes (Lip-TMZ) and PEGylated nanoliposomes (PEG-Lip/TMZ). The release behaviors of TMZ from PEG-Lip/TMZ and tLyP-1-Lip/TMZ are similar and slower than TMZ-Lip in acidic solutions. The tLyP-1-Lip/TMZ demonstrated the strongest cytotoxicity in comparison with TMZ-Lip and PEG-Lip/TMZ in both U87 and HT22 cells, and displayed the highest cellular internalization. The pharmacokinetic studies in rats revealed that tLyP-1-Lip/TMZ showed a 1.4-fold (p < 0.001) increase in AUCINF_obs and a 1.4-fold decrease (p < 0.01) in clearance compared with PEG-Lip/TMZ. We finally confirmed by in vivo imaging that tLyP-1-Lip were able to penetrate the brains and tumors of mice.


Assuntos
Células Endoteliais , Glioma , Ratos , Camundongos , Animais , Lipossomos , Glioma/tratamento farmacológico , Polietilenoglicóis/química , Temozolomida , Linhagem Celular Tumoral
7.
Environ Toxicol ; 38(3): 694-700, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36454668

RESUMO

2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), as an emerging disinfection by-product, has been frequently detected in waters, posing potential health risk on public health. Although some studies have pointed out that 2,6-DCBQ exposure can induce cytotoxicity, limited information is available for underlying mechanism for 2,6-DCBQ-induced cytotoxicity. To explore this mechanism, we assessed the levels of reactive oxygen species (ROS), acridine orange (AO) staining, and the mRNA transcriptions of genes (Chk2, Cdk2, Ccna, Ccnb and Ccne) involved in cell-cycle and genes (p53, bax, bcl-2 and caspase 3) involved in apoptosis in zebrafish embryo, after exposed to different concentrations (10, 30, 60, 90 and 120 µg/L) of 2,6-DCBQ for 72 h. Our results indicated that 2,6-DCBQ exposure induced ROS generation and cell apoptosis, and disturbed the mRNA transcription of genes related to cell cycle and apoptosis in zebrafish embryo. Moreover, we also found that 30 ~ 60 µg/L 2,6-DCBQ is the important transition from cell-cycle arrest to cell apoptosis. These results provided novel insight into 2,6-DCBQ-induced cytotoxicity.


Assuntos
Apoptose , Peixe-Zebra , Animais , Espécies Reativas de Oxigênio/metabolismo , Peixe-Zebra/metabolismo , Apoptose/genética , Pontos de Checagem do Ciclo Celular , RNA Mensageiro/metabolismo
8.
Pharm Biol ; 61(1): 790-798, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37161881

RESUMO

CONTEXT: Acacetin is reported as a potential drug candidate for the treatment of atrial fibrillation. However, clinical applications are limited by poor water solubility, limited ethanol solubility, and extremely low oral bioavailability. OBJECTIVE: The present study prepared and evaluated acacetin-loaded microemulsion (ME) to achieve efficient pharmacokinetics together with no or minimal invasiveness for transdermal delivery. MATERIALS AND METHODS: The formulation of ME was determined by the water titration method based on solubility results. The optimized formulation was achieved by the simplex lattice experiment design. The optimized ME formulations FA, FB and FC (FA with 10% and 50% DMSO as enhancers, respectively) were evaluated by ex vivo permeation with Franz diffusion cell and excised mice skin. In vivo pharmacokinetic studies were also performed at 8 mg/kg in rats within 6 h by transdermal administration. RESULTS: The optimal ME (FA) was comprised of 12.2% caprylic acid decanoate monoditriglyceride (MCF-NF), 39.8% Smix (RH40: Trans = 2:1 w/w) and 48% water, respectively. Acacetin-loaded FA with particle size 36.0 ± 3.6 nm and drug solubility 803.7 ± 32.1 mg/g was prepared. FB had significantly higher cumulative amounts and higher AUC0-∞ (196.6 ± 11.0 min × µg/mL, p < 0.05) than that FA alone (121.4 ± 33.1 min × µg/mL). DISCUSSION AND CONCLUSIONS: The formulation of ME combined with the penetration enhancer can effectively improve the solubility and percutaneous absorption efficiency of acacetin, providing a new option for the non-invasive delivery of acacetin.


Assuntos
Flavonas , Camundongos , Animais , Ratos , Administração Cutânea , Disponibilidade Biológica , Água
9.
J Liposome Res ; 32(1): 92-103, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34890290

RESUMO

In the present study, nanoliposomes with tuneable structure elasticity were prepared by reverse-phase evaporation. Both Fluorescence Polarization and Fluorescence Resonance Energy Transfer was employed to characterize the structural elasticity of resultant nanoliposomes. Temozolomide, a kind of hydrophilic drug as the first-line treatment choice for glioblastoma, was encapsulated into nanoliposomes. The results showed that the flexibility of nanoliposomes gradually increased with sodium cholate, while decreasing with cholesterol, Labrafac CC and Labrafac PG adding. Furthermore, the structural flexibility of nanoliposomes was positively correlated with the encapsulation efficiency and release rate and cellular uptake. Our research reveals the structural flexibility of nanoliposomes could affect in vitro characteristics and thereafter in vivo behaviors of nanoliposomes.


Assuntos
Lipossomos , Nanopartículas , Antioxidantes/química , Colesterol/química , Lipossomos/química , Nanopartículas/química , Tamanho da Partícula
10.
Sensors (Basel) ; 22(17)2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36081102

RESUMO

As a result of human activity and environmental changes, several types of damages may occur to ancient mural paintings; indeed, lacunae, which refer to the area of paint layer loss, are the most prevalent kind. The presence of lacuna is an essential sign of the progress of mural painting deterioration. Most studies have focused on detecting and removing cracks from old paintings. However, lacuna extraction has not received the necessary consideration and is not well-explored. Furthermore, most recent studies have focused on using deep learning for mural protection and restoration, but deep learning requires a large amount of data and computational resources which is not always available in heritage institutions. In this paper, we present an efficient method to automatically extract lacunae and map deterioration from RGB images of ancient mural paintings of Bey's Palace in Algeria. Firstly, a preprocessing was applied using Dark Channel Prior (DCP) to enhance the quality and improve visibility of the murals. Secondly, a determination of the training sample and pixel's grouping was assigned to their closest sample based on Mahalanobis Distance (MD) by calculating both the mean and variance of the classes in three bands (R, G, and B), in addition to the covariance matrix of all the classes to achieve lacuna extraction of the murals. Finally, the accuracy of extraction was calculated. The experimental results showed that the proposed method can achieve a conspicuously high accuracy of 94.33% in extracting lacunae from ancient mural paintings, thus supporting the work of a specialist in heritage institutions in terms of the time- and cost-consuming documentation process.


Assuntos
Pinturas , Argélia , Humanos , Aumento da Imagem/métodos , Pintura
11.
Int J Mol Sci ; 22(11)2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073595

RESUMO

Urolithins (hydroxylated 6H-benzo[c]chromen-6-ones) are the main bioavailable metabolites of ellagic acid (EA), which was shown to be a cognitive enhancer in the treatment of neurodegenerative diseases. As part of this research, a series of alkoxylated 6H-benzo[c]chromen-6-one derivatives were designed and synthesized. Furthermore, their biological activities were evaluated as potential PDE2 inhibitors, and the alkoxylated 6H-benzo[c]chromen-6-one derivative 1f was found to have the optimal inhibitory potential (IC50: 3.67 ± 0.47 µM). It also exhibited comparable activity in comparison to that of BAY 60-7550 in vitro cell level studies.


Assuntos
Benzopiranos , Desenho de Fármacos , Inibidores Enzimáticos , Exonucleases/antagonistas & inibidores , Benzopiranos/síntese química , Benzopiranos/química , Benzopiranos/farmacologia , Linhagem Celular , Avaliação de Medicamentos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Exonucleases/metabolismo , Humanos , Estrutura Molecular , Relação Estrutura-Atividade
12.
Pharm Biol ; 59(1): 418-423, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33847209

RESUMO

CONTEXT: Resveratrol has shown anti-stress and anti-depressant-like abilities involved in inhibiting phosphodiesterase-4 (PDE4) enzyme. However, its application is limited due to its low efficacy, bioavailability and selectivity. OBJECTIVE: This study synthesized a new resveratrol derivative RES003 and evaluated its PDE4 inhibitory and anti-depressant-like activities in vitro and in vivo, respectively. MATERIALS AND METHODS: PDEs inhibitory activities were evaluated by radioactive tracer method. Anti-depressant-like activities of novel resveratrol analogue (RES003) at doses of 2.5, 5.0 and 10 mg/kg was investigated by sugar water consumption and forced swimming tests using male ICR mice under chronic unpredictable stress procedure for 10 days. A total of 84 mice were randomly distributed into seven groups (n = 12). Drugs and vehicle were administered (intra-gastric or intra-peritoneal) once a day from the first to the last day. The molecular mechanisms were identified by western blot. RESULTS: RES003 showed more potent PDE4 inhibitory activity (half maximal inhibitory concentration (IC50), 0.87 µM) and better selectivity than resveratrol (IC50, 18.8 µM). RES003 could significantly increase the consumption of sugar water (p < 0.01) and immobility time (p < 0.01) compared to vehicle-treated stressed groups at doses of 5 and 10 mg/kg. Furthermore, RES003 could significantly increase the levels of cyclic adenosine monophosphate response element binding protein phosphorylation (10 mg/kg, p < 0.05) and brain-derived neurotrophic factor (BDNF) expression (5 and 10 mg/kg, p < 0.05 and 0.01) in mouse brain. DISCUSSION AND CONCLUSIONS: RES003 could ameliorate chronic stress induced depression-like behaviours through inhibition of PDE4 and activation of cAMP-triggered phosphorylation of cAMP response element binding protein/BDNF signalling pathway. Consequently, RES003 is a promising lead compound for the treatment of depression.


Assuntos
Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Inibidores da Fosfodiesterase 4/farmacologia , Resveratrol/farmacologia , Animais , Antidepressivos/administração & dosagem , AMP Cíclico/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Concentração Inibidora 50 , Masculino , Camundongos , Camundongos Endogâmicos ICR , Inibidores da Fosfodiesterase 4/administração & dosagem , Resveratrol/análogos & derivados , Transdução de Sinais/efeitos dos fármacos , Estresse Psicológico/tratamento farmacológico
13.
Bioorg Med Chem Lett ; 30(9): 127097, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32171616

RESUMO

A series of novel rutaecarpine derivatives were synthesized and subjected to pharmacological evaluation as PDE5 inhibitors. The structure-activity relationships were discussed and their binding conformation and simultaneous interaction mode were further clarified by the molecular docking studies. Among the 25 analogues, compound 8i exhibited most potent PDE5 inhibition with IC50 values about 0.086 µM. Moreover, it also produced good effects against scopolamine-induced cognitive impairment in vivo. These results might bring significant instruction for further development of potential PDE5 inhibitors derived from rutaecarpine as a good candidate drug for the treatment of Alzheimer's disease.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Disfunção Cognitiva/induzido quimicamente , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Alcaloides Indólicos/química , Inibidores da Fosfodiesterase 5/síntese química , Inibidores da Fosfodiesterase 5/farmacologia , Quinazolinas/química , Animais , Antagonistas Colinérgicos/toxicidade , Disfunção Cognitiva/tratamento farmacológico , Relação Dose-Resposta a Droga , Camundongos , Modelos Moleculares , Estrutura Molecular , Teste do Labirinto Aquático de Morris , Inibidores da Fosfodiesterase 5/administração & dosagem , Inibidores da Fosfodiesterase 5/química , Conformação Proteica , Escopolamina/toxicidade
14.
Bioorg Med Chem Lett ; 29(3): 481-486, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30554955

RESUMO

Phosphodiesterase 2 (PDE2) has received much attention for the potential treatment of the central nervous system (CNS) disorders. Herein, based on the existing PDE2 inhibitors and their binding modes, a series of purin-6-one derivatives were designed, synthesized and evaluated for PDE2 inhibitory activities, which led to the discovery of the best compounds 6p and 6s with significant inhibitory potency (IC50: 72 and 81 nM, respectively). Docking simulation was performed to insert compound 6s into the crystal structure of PDE2 at the active site to determine the binding mode. Furthermore, compound 6s significantly protected HT-22 cells against corticosterone-induced cytotoxicity and rescued corticosterone-induced decreases in cAMP and cGMP levels. It also produced anxiolytic-like effect in the elevated plus-maze test and exhibited favorable pharmacokinetic properties in vivo. These results might bring significant instruction for further development of potent PDE2 inhibitors.


Assuntos
Ansiolíticos/farmacologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 2/antagonistas & inibidores , Desenho de Fármacos , Fármacos Neuroprotetores/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Purinonas/farmacologia , Animais , Ansiolíticos/síntese química , Ansiolíticos/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 2/metabolismo , Relação Dose-Resposta a Droga , Humanos , Camundongos , Estrutura Molecular , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/química , Purinonas/síntese química , Purinonas/química , Relação Estrutura-Atividade
15.
Environ Sci Technol ; 53(4): 2036-2044, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30653306

RESUMO

Traditional processes usually cannot enable efficient water decontamination from toxic heavy metals complexed with organic ligands. Herein, we first reported the removal of Cu(II)-EDTA by a UV/chlorine process, where the Cu(II)-EDTA degradation obeyed autocatalytic two-stage kinetics, and Cu(II) was simultaneously removed as CuO precipitate. The scavenging experiments and EPR analysis indicated that Cl• accounted for the Cu(II)-EDTA degradation at diffusion-controlled rate (∼1010 M-1 s-1). Mechanism study with mass spectrometry evidence of 11 key intermediates revealed that the Cu(II)-EDTA degradation by UV/chlorine was an autocatalytic successive decarboxylation process mediated by the Cu(II)/Cu(I) redox cycle. Under UV irradiation, Cu(I) was generated during the photolysis of the Cl•-attacked complexed Cu(II) via ligand-to-metal charge transfer (LMCT). Both free and organic ligand-complexed Cu(I) could form binary/ternary complexes with ClO-, which were oxidized back to Cu(II) via metal-to-ligand charge transfer (MLCT) with simultaneous production of Cl•, resulting in the autocatalytic effect on Cu(II)-EDTA removal. Effects of chlorine dosage and pH were examined, and the technological practicability was validated with authentic electroplating wastewater and other Cu(II)-organic complexes. This study shed light on a new mechanism of decomplexation by Cl• and broadened the applicability of the promising UV/chlorine process in water treatment.


Assuntos
Cloro , Purificação da Água , Ácido Edético , Raios Ultravioleta , Águas Residuárias
16.
J Environ Sci (China) ; 54: 231-238, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28391934

RESUMO

Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol (4-BP) by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH (6.1-10) and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing N2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br-, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process.


Assuntos
Retardadores de Chama , Modelos Químicos , Fenóis/química , Raios Ultravioleta , Halogenação , Cinética , Sulfitos/química
17.
Proc Natl Acad Sci U S A ; 110(34): 13774-9, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23918373

RESUMO

Understanding of the mechanisms driving our daily face-to-face encounters is still limited; the field lacks large-scale datasets describing both individual behaviors and their collective interactions. However, here, with the help of travel smart card data, we uncover such encounter mechanisms and structures by constructing a time-resolved in-vehicle social encounter network on public buses in a city (about 5 million residents). Using a population scale dataset, we find physical encounters display reproducible temporal patterns, indicating that repeated encounters are regular and identical. On an individual scale, we find that collective regularities dominate distinct encounters' bounded nature. An individual's encounter capability is rooted in his/her daily behavioral regularity, explaining the emergence of "familiar strangers" in daily life. Strikingly, we find individuals with repeated encounters are not grouped into small communities, but become strongly connected over time, resulting in a large, but imperceptible, small-world contact network or "structure of co-presence" across the whole metropolitan area. Revealing the encounter pattern and identifying this large-scale contact network are crucial to understanding the dynamics in patterns of social acquaintances, collective human behaviors, and--particularly--disclosing the impact of human behavior on various diffusion/spreading processes.


Assuntos
Cidades , Atividades Humanas/estatística & dados numéricos , Relações Interpessoais , Dinâmica Populacional , Humanos , Modelos Teóricos , Veículos Automotores/estatística & dados numéricos , Fatores de Tempo
18.
Chemosphere ; 349: 140912, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38065259

RESUMO

Nanoscale hydrated zirconium oxide (HZO) holds great potential in groundwater purification due to its ability to form inner-sphere coordination with arsenate. Despite being frequently used, especially as encapsulations in host materials for practical application in water treatment, the adsorption mechanisms of solutes on HZO are not appropriately explored, in particular for arsenate adsorption. In this study, we investigated the Zr-As coordination configuration and identified the most credible Zr-As configuration using surface complexation modeling (SCM), XPS and FT-IR analysis. The corresponding intrinsic coordination constants (Kintr) values was calculated by SCM, and the nanoconfinement effects were distinguished by comparing bare HZO with the HZO nanoparticles (NPs) encapsulated inside the strongly basic anion exchanger D201. Potentiometric titration suggests that the surface Zirconium hydroxyl groups (≡ZrOH) mainly exist in protonated form (≡ZrOH2+). Batch adsorption experiments demonstrate that the D201 hosts could adsorb As(V) through ion exchange by the quaternary ammonium groups under the low ionic strength (≤0.01 M NaNO3) and at pH > 6. The nanocomposite (HZO@D201) exhibits a higher adsorption capacity in a wide range of pH (3-10) and ionic strength (0.001-0.1 M NaNO3) than bare HZO. SCM simulations reveal that the coordination configuration of diprotonated monodentate mononuclear (MM-H2) dominates at pH 3-6, while deprotonated bidentate binuclear (BB-H0) dominates at pH > 7. For each configuration, the intrinsic coordination constants (Kintr) of HZO@D201 (10-0.66 and 10-16.10, respectively) are significantly higher than those of bare HZO (10-12.24 and 10-44.42, respectively), indicating a superior chemical bonding affinity caused by nanoconfinement. The obtained Kintr values are used to predict arsenate adsorption isotherms in pH 3 and 9, and the results align with the SCM simulation outcomes. This study may offer a feasible method for investigating the nanoconfinement effect of emerging nanocomposite adsorbents from a thermodynamic perspective, and provide reference coordination equilibrium constants of HZO for research and practical application.


Assuntos
Arseniatos , Poluentes Químicos da Água , Zircônio , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Adsorção , Óxidos , Concentração de Íons de Hidrogênio
19.
Artigo em Inglês | MEDLINE | ID: mdl-38956918

RESUMO

Diabetes mellitus is a common chronic metabolic disease characterized by a high incidence and disability rate. Intestinal flora refers to the microbial community that lives in the intestines and plays a crucial role in maintaining intestinal health and the human immune system. In recent years, an increasing body of research has revealed a close relationship between intestinal flora and diabetes. The pathophysiological mechanisms between them have also been constantly uncovered, and the regulation of intestinal flora has shown promising efficacy in the adjuvant treatment of diabetes. This study mainly summarized the characteristics and mechanisms of intestinal flora in patients with diabetes in recent years, as well as the methods of regulating intestinal flora to prevent and treat diabetes, and prospected the future research direction. This will offer a theoretical basis for the clinical adjuvant treatment of diabetes with intestinal flora and the development of new drugs.

20.
Spectrochim Acta A Mol Biomol Spectrosc ; 318: 124468, 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-38761475

RESUMO

Rapid and quantitative detection of 2,4,6-trinitrophenol (TNP) is very crucial for homeland security, military application, and environment protection. Herein, a nine-metal Zn(II)-Nd(III) nanoring 1 with a diameter of 2.3 nm was constructed by the use of a long-chain Schiff base ligand, which shows ratiometric fluorescence response to TNP with high selectivity and sensitivity. The fluorescence sensing behavior of 1 to TNP is expressed by a first-order equation I1060nm/I560nm = -0.0128*[TNP] + 0.9723, which can be used to quantitatively analyze TNP concentrations in solution. The limits of detection (LODs) to TNP based on the ligand-centered (LC) and Nd(III) emissions of 1 are 5.93 µM and 3.18 µM, respectively. The fluorescence response mechanism to TNP is attributed to the competitive absorption effect and photoinduced electron transfer (PET). The luminescence quenching of 1 is dominated by static process.

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