Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
ACS Nano ; 18(14): 10063-10073, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38533795

RESUMO

We developed an intrinsic hydrophilic single-atom iron nanobowl (Fe-SANB) for magnetic resonance imaging (MRI)-guided tumor microenvironment-triggered cancer therapy. Benefiting from the sufficient exposure of Fe single atoms and the intrinsic hydrophilicity of the bowl-shaped structure, the Fe-SANBs exhibited a superior performance for T1-weighted MRI with an r1 value of 11.48 mM-1 s-1, which is 3-fold higher than that of the commercial Gd-DTPA (r1 = 3.72 mM-1 s-1). After further coembedding Gd single atoms in the nanobowls, the r1 value can be greatly improved to 19.54 mM-1 s-1. In tumor microenvironment (TME), the Fe-SANBs can trigger pH-induced Fenton-like activity to generate highly toxic hydroxyl radicals for high-efficiency chemodynamic therapy (CDT). Both the MRI and CDT efficiency of these nanobowls can be optimized by tuning the ratio of Fe(II)/Fe(III) in the Fe-SANBs via controlling the calcination temperature. Furthermore, the generation of •OH at the tumor site can be accelerated via the photothermal effect of Fe-SANBs, thus promoting CDT efficacy. Both in vitro and in vivo results confirmed that our nanoplatform exhibited high T1-weighted MRI contrast, robust biocompatibility, and satisfactory tumor treatment, providing a potential nanoplatform for MRI-guided TME-triggered precise cancer therapy.


Assuntos
Nanopartículas , Neoplasias , Humanos , Compostos Férricos , Imageamento por Ressonância Magnética , Meios de Contraste , Microambiente Tumoral , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Compostos Ferrosos , Linhagem Celular Tumoral , Peróxido de Hidrogênio
2.
ACS Appl Mater Interfaces ; 16(2): 2606-2613, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38175744

RESUMO

Constructing heterostructures of dual quantum-dots (QDs) is a promising way to achieve high performance in photocatalysis, but it still faces substantial synthetic challenges. Herein, we developed an in situ transformation strategy to coassemble ZnS QDs and C QDs into dual-quantum-dot heterostructural nanofibers (ZnS/C-DQDH). Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results revealed the formation of strong Zn-O-C bonds at the interface between ZnS QDs and C QDs, improving the separation efficiency of photogenerated charge carriers. The ZnS/C-DQDH demonstrated remarkable photocatalytic activity in H2O2 production, with generation rates of 2896.4 µmol gcat-1 h-1 without sacrificial agents and 9879.3 µmol gcat-1 h-1 with ethanol as the sacrificial agent, significantly higher than the QD counterparts and surpassed state-of-the-art photocatalysts. Moreover, due to the nanofibrous feature, ZnS/C-DQDH demonstrated excellent stability and facile recyclability. This work provides a facile and large scalable method to gain dual-quantum-dot heterostructures and a promising alternative for photocatalytic H2O2 production.

3.
Molecules ; 27(8)2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35458658

RESUMO

Herein, novel visible light active graphitic carbon nitride (g-C3N4)/sepiolite fiber (CN/SS) composites were fabricated via a facile calcination route, exploiting melamine and thiourea as precursors, and sepiolite fiber as support, for efficient degradation of organic dye methylene blue (MB). The as-prepared CN/SS composites were characterized by various characterization techniques based on structural and microstructural analyses. The effects of CN loading amount, catalyst dosage and initial concentration of dye on the removal rate of dye under visible light were systematically studied. The removal rate of MB was as high as 99.5%, 99.6% and 99.6% over the composites when the CN loading amount, catalyst dosage and initial concentration of dye were 20% (mass percent), 0.1 g, and 15 mg/L in 120 min, respectively. The active species scavenging experiments and electron paramagnetic resonance (EPR) measurement indicated that the holes (h+), hydroxyl radical (·OH) and superoxide radicals (·O2-) were the main active species. This study provides for the design of low-cost, environmentally friendly and highly efficient catalysts for the removal of organic dye.


Assuntos
Luz , Silicatos de Magnésio , Catálise , Azul de Metileno/química
4.
Chemistry ; 28(26): e202104247, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35191569

RESUMO

Nanomaterials with oxidase- and peroxidase-like activities have potential in antibacterial therapy. The optimal activity of most nanozymes occurred in acidic pH (3.0-5.0), while the pH in biological systems is mostly near neutral. Herein, a general system using 9-fluorenylmethoxycarbonyl-modified diphenylalanine (Fmoc-FF) hydrogel for enhancing oxidase- and peroxidase-like activities of Pt NPs and other typical enzyme-like nanomaterials at neutral or even alkaline pH is proposed. In this system, Fmoc-FF hydrogel provides an acidic microenvironment for Pt NPs due to hydrogen protons (H+ ) produced by the dissociation of F at neutral pH. As a result, Pt NPs exhibits 6-fold enhanced oxidase-like and 26-fold peroxidase-like activity after being encapsulated into Fmoc-FF hydrogel at pH 7.0. Based on outstanding enzymatic activities and the antibacterial activity of Fmoc-FF hydrogel itself, Pt-Fmoc-FF hydrogel realizes excellent antibacterial effect. This design provides a universal strategy to break pH limitation of nanozymes and promotes the biological applications of nanozymes.


Assuntos
Hidrogéis , Peroxidase , Antibacterianos/farmacologia , Corantes , Concentração de Íons de Hidrogênio , Oxirredutases , Fenilalanina
5.
Nat Aging ; 1(1): 87-100, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-37118004

RESUMO

Lifelong sex- and age-related trajectories of the human gut microbiota remain largely unexplored. Using metagenomics, we derived the gut microbial composition of 2,338 adults (26-76 years) from a Han Chinese population-based cohort where metabolic health, hormone levels and aspects of their lifestyles were also recorded. In this cohort, and in three independent cohorts distributed across China, Israel and the Netherlands, we observed sex differences in the gut microbial composition and a shared age-related decrease in sex-dependent differences in gut microbiota. Compared to men, the gut microbiota of premenopausal women exhibited higher microbial diversity and higher abundances of multiple species known to have beneficial effects on host metabolism. We also found consistent sex-independent, age-related gut microbial characteristics across all populations, with the presence of members of the oral microbiota being the strongest indicator of older chronological age. Our findings highlight the existence of sex- and age-related trajectories in the human gut microbiota that are shared between populations of different ethnicities and emphasize the pivotal links between sex hormones, gut microbiota and host metabolism.


Assuntos
Microbioma Gastrointestinal , Microbiota , Humanos , Feminino , Adulto , Masculino , Microbioma Gastrointestinal/genética , Fezes , Etnicidade , Metagenômica
6.
Chem Commun (Camb) ; 57(6): 769-772, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33355561

RESUMO

Encapsulating metal nanoparticles with a graphitic carbon shell to remit the loss of active sites has drawn attention in catalysis. Herein, we report the development of a facile strategy to prepare graphitic carbon encapsulated Cu nanoparticle (Cu@C) nanofibers by in situ pyrolysis of organic-layered copper hydroxides, which exhibited superior activity and durability for water splitting.

7.
J Diabetes ; 13(6): 512-520, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33249774

RESUMO

OBJECTIVE: To explore the impact of ferritin level on the disassociation of glycated hemoglobin A1c (HbA1c) and mean plasma glucose (MPG). RESEACH DESIGN AND METHODS: We used a 2012-2013 cross-sectional survey conducted in Pinggu district, Beijing including 3095 Chinese participants aged 25-75 years. We categorized their glycemic status by interviewing for diagnosed diabetes and by measuring HbA1c, fasting plasma glucose (FPG), and 2-hours post-load plasma glucose (2-hours PPG). We fitted a multivariable regression model to explore the impact of ferritin on the association of HbA1c or glycated albumin (GA) and mean plasma glucose. RESULTS: A total of 5.65% of participants were diagnosed as diabetes using HbA1c criteria, and 9.79% using oral glucose tolerance test criteria. Compared with males, females had significantly lower hemoglobin levels (159.82 ± 11.56 vs 135.93 ± 12.62) and lower ferritin levels (113.00 [68.55, 185.50] vs 33.40 [12.40, 70.13]). Linear regression analysis performed in different groups classified by different diagnose criterion indicated that the correlation between MPG and HbA1c differs in different tertiles of ferritin (lowest vs middle vs highest: R2 = 0.507 vs 0.645 vs 0.687 in female; R2 = 0.415 vs 0.715 vs 0.615 in male), and the association between MPG and HbA1c diminished in the lowest tertile of ferritin. CONCLUSIONS: Ferritin level might affect the association between glucose and HbA1c, which should be taken into account when using HbA1c as a diagnosis criterion for diabetes and prediabetes.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus/sangue , Ferritinas/sangue , Hemoglobinas Glicadas/metabolismo , Adulto , Idoso , Pequim/epidemiologia , Biomarcadores/sangue , Estudos Transversais , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
8.
Diabetes Metab Syndr Obes ; 13: 2001-2011, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606859

RESUMO

PURPOSE: We aimed to ascertain the association between thyrotropin (TSH) levels in euthyroid state and the prevalence of metabolic syndrome (MetS) in a community-based Chinese population. PARTICIPANTS AND METHODS: Based on a large and well-characterized community cohort in Beijing, China, 1831 men and 1742 women with serum TSH levels within the reference range (0.50-4.78 µIU/mL) were stratified by quartiles of TSH (Q1-4). MetS was identified according to the criteria of International Diabetes Federation guidelines. Poisson regression models were used to estimate the association between serum TSH and the prevalence of MetS and its components before and after adjustment for potential confounding factors. The reported association was measured using the prevalence ratio (PR) with its respective 95% confidence interval (95% CI). RESULTS: The prevalence of MetS in euthyroid population across TSH quartiles (Q1-4) was 38.9%, 44.6%, 41.0%, and 47.7%, respectively, in men (P = 0.045), and 47.7%, 46.6%, 46.9%, and 54.6%, respectively, in women (P = 0.032). Compared with the reference group TSH-Q1, the prevalence of MetS was higher among TSH-Q4 group both in men (PR = 1.27; 95% CI: 1.09, 1.48, P = 0.002) and women (PR = 1.21; 95% CI: 1.07, 1.37, P = 0.003) even after adjustment for age, lifestyle factors, serum levels of free triiodothyronine (FT3), and free thyroxine (FT4). Most of the components of MetS were common in higher serum TSH levels within the normal range. CONCLUSION: The prevalence of MetS and most of its components increased in the higher TSH group in euthyroid Chinese population.

9.
Metab Syndr Relat Disord ; 18(6): 284-290, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32460629

RESUMO

Objective: To investigate the morbidity and comorbidity of nonalcoholic fatty liver disease (NAFLD) and different glucose intolerance strata in a community-based population and to explore the association between glucose tolerance levels and NAFLD. Methods: A community-based cohort established for Pinggu Metabolic Disease Study in a suburb of Beijing, China, was established from September 2013 to July 2014 using a random sampling method. Participants were eligible if they were born in Pinggu and had been living there for at least 5 years within the age range of 26-76 years. A 75 grams oral glucose tolerance test was used to determine the strata of glucose tolerance. Unenhanced abdominal computed tomography scan was performed to identify NAFLD. Results: A total of 3122 subjects were included in this analysis. The prevalence of NAFLD was 22.68% (27.58% vs. 19.97% among men and women). The prevalence of type 2 diabetes (T2D) was 18.03% (20.83% vs. 16.22% among men and women). Up to 7.21% of residents had both T2D and NAFLD. 39.96% of diabetic patients and 28.77% of prediabetic patients combined with NAFLD. Compared with adults with normal glucose tolerance, the incidence of NAFLD in T2D patients was more than three times higher after adjusting for sex, age, body mass index (BMI), sedentary time, and dietary habit [odds ratio (OR) = 3.58, confidence interval (95% CI) 2.80-4.58, P < 0.001]. NAFLD was also more common in individuals with prediabetes, especially patients with impaired glucose tolerance (IGT) (OR = 2.27, 1.75-2.95) or impaired fasting glucose+IGT (OR = 2.78, 1.92-4.03). Conclusions: The morbidity and comorbidity of NAFLD and glucose intolerance are high in the Pinggu population in northern China, highlighting the importance of early prevention and treatment of these two diseases at the same time.


Assuntos
Glicemia/análise , Intolerância à Glucose/epidemiologia , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Adulto , Idoso , Pequim/epidemiologia , Biomarcadores/sangue , Comorbidade , Feminino , Intolerância à Glucose/sangue , Intolerância à Glucose/diagnóstico , Teste de Tolerância a Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Prevalência , Medição de Risco , Fatores de Risco , Tomografia Computadorizada por Raios X
10.
Chem Commun (Camb) ; 56(34): 4680-4683, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32211705

RESUMO

For the first time, electrochemiluminescence (ECL) emission was observed from black phosphorus quantum dots (BPQDs) in the presence of K2S2O8 as the co-reactant. The potential application of BPQDs ECL in analytical chemistry was also demonstrated using Cu2+ as an example.

11.
BMC Public Health ; 19(1): 1498, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31706298

RESUMO

BACKGROUND: The prevalence of type 2 diabetes has grown significantly in China. However, little is known about the survival outcome of people with type 2 diabetes and diabetic kidney disease (DKD). The purpose of this study is to examine the survival of this population and the risk factors for mortality in one suburb cohort of Beijing, China. METHODS: Four hundred and forty-five people with DKD (48.8% male, age at onset of diabetes 48.8 ± 11.0 years, age at enrollment 57.5 ± 11.6 years) were enrolled in one suburb of Beijing, China between January 1st, 2003 and December 31st, 2015. Mortality ascertainment was censored by December 31st, 2015. Survival analysis was performed by Kaplan-Meier analysis, and Cox proportional hazards regression models were served for risk factor analysis of mortality. The Chiang method was used to estimate life expectancy by age. RESULTS: A total of 78 deaths were identified during the 3232 person-years of follow-up. Multivariate Cox regression analysis showed significantly higher risks of mortality with respect to older age, higher systolic blood pressure (SBP), lower body mass index (BMI) and lower estimated glomerular filtration rate (eGFR). The life expectancy at age of 50 was estimated to be 12.3 (95%, CI: 9.0-16.1) years. Circulatory disease was the leading cause of death in this population (accounting for 43.6% of all deaths), followed by diabetic complications (33.3%) and respiratory disease (6.4%). CONCLUSIONS: Data from one Chinese cohort from 2003 through 2015 showed that people with DKD faced higher risk of death and shorter life expectancy. Factors significantly increasing risk of death included older age, higher SBP, lower BMI and lower eGFR. There is an urgent need to early detection, closely monitoring and effective intervention on DKD.


Assuntos
Complicações do Diabetes/mortalidade , Diabetes Mellitus Tipo 2/mortalidade , Nefropatias Diabéticas/mortalidade , Adulto , Idoso , Povo Asiático/estatística & dados numéricos , Índice de Massa Corporal , China/epidemiologia , Feminino , Seguimentos , Taxa de Filtração Glomerular , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Taxa de Sobrevida
12.
Artif Cells Nanomed Biotechnol ; 47(1): 3548-3558, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31456420

RESUMO

The extensive relevance of nanoparticles arouses the requirement for manufacturing although the predictable technique are frequently perilous and energy saving. In the current study, zinc oxide nanoparticles manufactured from Allium cepa avert UVB radiation interceded irritation in human epidermal keratinocytes (HaCaT cells). In the current study, the zinc oxide nanoparticles (ZnO-NPs) was synthesized from the extract of A. cepa. The optimized ZnO-NPs hence attained and was enumerated and exemplified by UV visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscope (SEM) and EDAX impending analysis. In addition, amalgamated ZnO-NPs were experienced for cell viability (MTT), formation of reactive oxygen species (ROS), apoptosis, and antioxidant and lipid peroxidation (TBARS) levels. Also, we explored the effect of A. cepa ZnO-NPs in molecular level by evaluating the inflammatory and apoptotic markers, in which ZnO-NPs reinstated the interleukins 6, 10 and related signaling molecules like iNOS, COX-2 levels. Ultimately, ZnO-NPs induce apoptotic markers (Bax, Bcl-2) and also recommended that ZnO-NPs might aggravate cancer cell apoptosis in HaCaT cells.


Assuntos
Epiderme/metabolismo , Queratinócitos/efeitos dos fármacos , Queratinócitos/efeitos da radiação , Cebolas/metabolismo , Raios Ultravioleta/efeitos adversos , Óxido de Zinco/química , Óxido de Zinco/farmacologia , Animais , Linhagem Celular , Humanos , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Inflamação/prevenção & controle , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Espaço Intracelular/efeitos da radiação , Queratinócitos/citologia , Queratinócitos/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Protetores contra Radiação/química , Protetores contra Radiação/metabolismo , Protetores contra Radiação/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Óxido de Zinco/metabolismo
13.
Analyst ; 144(11): 3635-3642, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31073579

RESUMO

The exploitation of highly soluble and responsive AIEgens is essential for further expansion of their practical applications. In this study, dipropyltrimethylammonium bromide-substituted TPE (denoted as o-TPEDTA), a homolateral and dicationic AIEgen, was synthesized and applied for the turn-on detection of casein via hydrophobic interactions. The rapid and sensitive detection of casein was achieved using the designed o-TPEDTA probe with the limit of detection of 0.05 µg mL-1. The satisfying selectivity of over 1000-fold concentration of other probably existing chemicals, including amino acids, sugars and salts, was achieved due to the strong binding affinity between o-TPEDTA and casein. The evaluation of casein in milk powder samples with small relative standard deviations was realized using the o-TPEDTA probe. The accuracy of the o-TPEDTA probe-based detection method was validated by the consistency of the casein detection results with those obtained via a national standard casein evaluation approach.

14.
Chin Med J (Engl) ; 132(9): 1015-1022, 2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-30925549

RESUMO

BACKGROUND: Large-nerve fiber dysfunction, as assessed by vibration perception threshold (VPT) predicts risks of ulceration, amputation, and mortality in diabetes. Serum uric acid (UA) is closely associated with various metabolic disorders, especially diabetes. Thus, we sought to investigate the clinical relevance of UA to large-nerve fiber dysfunction, among patients with type 2 diabetes (T2D). METHODS: Medical records of consecutive patients with T2D who were admitted to Beijing Friendship Hospital Pinggu Campus between May 2014 and December 2016 were collected. Data for the 824 eligible patients included in the final analysis were extracted using a structured form. A VPT value ≥15 in either foot was defined as abnormal. We compared the clinical characteristics between patients with abnormal VPT and those with normal VPT (VPT value <15 in both feet) in the overall population and in gender subgroups. Logistic regression analysis was performed to explore the association of abnormal VPT with UA level. One-way analysis of variance was used to compare VPT values across four UA quartiles. RESULTS: UA levels were significantly lower in T2D patients with abnormal VPT than in those with normal VPT (294.5 ±â€Š84.0 vs. 314.9 ±â€Š92.8 µmol/L, P < 0.01), especially among male patients (311.7 ±â€Š85.2 vs. 336.9 ±â€Š89.6 µmol/L, P < 0.01). From the logistic regression analysis, hyperuricemia (males >420 µmol/L; females >360 µmol/L) was associated with a reduced risk of abnormal VPT (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.39-0.91; P < 0.05). This association was robust in male patients (OR, 0.43; 95% CI, 0.24-0.76; P < 0.01) but not in female patients (OR, 0.92; 95% CI, 0.47-1.82; P = 0.816), even after adjustment for confounding factors. For the younger male subgroup (age <65 years), VPT values decreased as the UA level increased (P for trend = 0.002), but this trend was not significant in older male subgroup (age ≥65 years; P for trend = 0.400). CONCLUSIONS: Low serum UA levels showed a significant association with an increased risk of large-nerve fiber dysfunction in male patients with T2D, but not in female patients with T2D. In addition, in only the younger subgroup of male patients (<65 years), lower levels of UA also correlated with higher VPT values.


Assuntos
Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/patologia , Fibras Nervosas/patologia , Ácido Úrico/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/sangue , Doenças do Sistema Nervoso Periférico/patologia , Adulto Jovem
15.
J Hazard Mater ; 369: 408-415, 2019 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-30784970

RESUMO

Fenton/Fenton-like reaction is often used as an efficient method to generate hydroxyl radicals (HO) for bacteria inactivation in aqueous solution. However, inactivation efficiency of bacteria in aqueous solution using Fenton/Fenton-like reactions needs to further improve as a result of transient generation of HO. In this paper, we found that the formation of Tris-Co(II) complexes could decrease the redox potential of Co(III)/Co(II), facilitating the transformation of Tris-Co(III) complexes into Tris-Co(II) complexes. Therefore, HO could be generated continuously in the presence of H2O2. Especially, Tris-Co(II) complexes are apt to combine with Escherichia Coli cells by electrostatic interactions, inducing a higher utilization ratio of the generated HO. Therefore, the proposed Tris-Co(II) complex-H2O2 system could be employed as a high-efficiency sterilizing reagent for inactivation of E. Coli. This work provides a promising strategy for bacterial inactivation via an economic and eco-friendly manner.


Assuntos
Antibacterianos/síntese química , Escherichia coli/efeitos dos fármacos , Radical Hidroxila , Ligantes , Química Orgânica , Cobalto/química , Corantes , Eletroquímica , Espectroscopia de Ressonância de Spin Eletrônica , Peróxido de Hidrogênio/química , Ferro/farmacologia , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Oxirredução , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Trometamina/química
16.
ACS Omega ; 4(26): 21704-21711, 2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31891049

RESUMO

The development of simple Fenton/Fenton-like systems with durative hydroxyl radical (•OH) generation characteristics is significant to rapid organic pollutant degradation and cost-effective water treatment. In this study, a tris(hydroxymethyl)aminomethane (Tris)-incorporated Co(II)-H2O2 Fenton-like system has been successfully constructed for efficient Sunset Yellow (SY, a typical anionic azo dye) degradation under alkaline conditions. The mechanism of the enhanced degradation consists of two parts: first, the Tris-Co(II) complex triggers the durative generation of highly oxidized hydroxyl radicals; second, electrostatic attraction between SY and the Tris-Co(II) complex shortens the radical-SY interaction time and facilitates the degradation of SY. With the introduction of Tris to this proposed system, the decolorization rate of SY can be increased from 37.0 to 98.0% after 50 min and efficient SY degradation with a high total organic carbon removal efficiency (>59.0%) is achieved under a wide initial pH from 8.7 to 12.0. Moreover, the universality of the designed system for anionic azo dye degradation is verified with reactive red and congo red.

17.
Chem Commun (Camb) ; 55(5): 679-682, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30565598

RESUMO

Luminol tablet-Tris-Co(ii) complex-PVP-H2O2 systems exhibit 13 hours of intensive and stable chemiluminescence (CL) due to the continuous generation of ˙OH and sustained-release. Multicolored chemical lights were prepared through CL resonance energy transfer. This work presents a new method for the fabrication of bright chemical lights in aqueous solution for emergencies.

18.
RSC Adv ; 8(29): 15999-16003, 2018 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35542221

RESUMO

Hollow hierarchical Ni@C nanocomposites with highly dispersed Ni nanoparticles (NPs) embedded in well-graphitized carbon matrix have been synthesized by solid-state pyrolysis of simple, well-defined organic-inorganic layered nickel hydroxide. The integration of highly dispersed Ni NPs, high Ni NPs content (up to ∼88.01 wt%), well-graphitized carbon as well as strong Ni/carbon interaction in the Ni@C make them display excellent catalytic activity and stable magnetic recyclability toward the reduction of 4-nitrophenol by NaBH4.

19.
Inorg Chem ; 53(24): 12841-7, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25423999

RESUMO

New pink organic-inorganic layered cobalt hydroxide nanofibers intercalated with benzoate ions [Co(OH)(C6H5COO)·H2O] have been synthesized by using cobalt nitrate and sodium benzoate as reactants in water with no addition of organic solvent or surfactant. The high-purity nanofibers are single-crystalline in nature and very uniform in size with a diameter of about 100 nm and variable lengths over a wide range from 200 µm down to 2 µm by simply adjusting reactant concentrations. The as-synthesized products are well-characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), fast Fourier transforms (FFT), X-ray diffraction (XRD), energy dispersive X-ray spectra (EDX), X-ray photoelectron spectra (XPS), elemental analysis (EA), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), and UV-vis diffuse reflectance spectra (UV-vis). Our results demonstrate that the structure consists of octahedral cobalt layers and the benzoate anions, which are arranged in a bilayer due to the π-π stacking of small aromatics. The carboxylate groups of benzoate anions are coordinated to Co(II) ions in a strong bridging mode, which is the driving force for the anisotropic growth of nanofibers. When NaOH is added during the synthesis, green irregular shaped platelets are obtained, in which the carboxylate groups of benzoate anions are coordinated to the Co(II) ions in a unidentate fashion. Interestingly, the nanofibers exhibit a reversible transformation of the coordination geometry of the Co(II) ions between octahedral and pseudotetrahedral with a concomitant color change between pink and blue, which involves the loss and reuptake of unusual weakly coordinated water molecules without destroying the structure. This work offers a facile, cost-effective, and green strategy to rationally design and synthesize functional nanomaterials for future applications in catalysis, magnetism, gas storage or separation, and sensing technology.

20.
Dalton Trans ; 43(22): 8254-60, 2014 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-24695765

RESUMO

Individual CoFe alloy nanoparticles and CoFe-MgO nanocomposites were prepared through thermal reduction of single-source layered double hydroxide (LDH) precursors at various temperatures. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) analyses to investigate the influence of reduction temperature on the composition, particle size and size distribution, as well as the magnetic properties of the resulting materials. XRD and SEM results show that the as-prepared CoFe alloy nanoparticles and CoFe-MgO nanocomposites display high crystallinity and high purity. The average particle size of individual CoFe nanoparticles increases with the increase of reduction temperature. In the presence of the MgO matrix, uniform CoFe alloy nanoparticles with a narrow diameter distribution (8-11 nm) were obtained. Magnetic measurements indicate that the saturation magnetization strength (Ms) of the resulting materials increases with reduction temperature. The individual CoFe alloy nanoparticles exhibit excellent soft magnetic behavior with an extremely high Ms value (213 emu g(-1) at 800 °C), comparable to that of bulk CoFe alloy (230 emu g(-1)). For CoFe-MgO nanocomposites, small Ms values were obtained due to the small CoFe alloy particle size and low percentage of magnetic component. However, the coercivities are greatly enhanced (663 Oe at 450 °C) for the composites, implying their potential applications in data storage and other magnetic devices.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...