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1.
Food Res Int ; 163: 112211, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36596142

RESUMO

Natural superoxide dismutase (SOD), consisting of proteins and metal cofactors, is widely used in food preservation because of its good antioxidant activity. However, due to the poor stability of SOD enzyme, its activity was reduced in the process of moving into the film, resulting in limited application. Based on the structure of the active site of the natural enzyme, Cu2+ was used to functionalize the melanin nanoparticles (NMPs) in ink of cuttlefish, and an SOD-like nanozyme (Cu-NMPs) with high stability, high activity and strong free radical scavenging capacity was constructed. In order to apply the constructed simulated enzyme to food preservation, the simulated enzyme was embedded into carrageenan (Carr) films to prepare the composite film for food packaging. The results showed that when the concentration of Cu-NMPs was 10 µg/mL, the ·O2- rate could reach more than 80 %, the activity exceeded that of 60 U/mL natural SOD. In addition, the fresh-keeping test of cherry tomatoes showed that Carr/Cu-NMPs composite film extended the storage time of cherry tomatoes by more 3 days. Therefore, the present work showed that nanozymes with advanced catalytic capabilities can be constructed by metal ions and NMPs, thus successfully combined with food packaging for food preservation.


Assuntos
Melaninas , Nanopartículas , Tinta , Superóxido Dismutase/metabolismo , Conservação de Alimentos , Metais
2.
Chemosphere ; 314: 137728, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36603679

RESUMO

A variety of photocatalytic systems have emerged as the effective methods for the degradation of organic pollutants. In this research, a novel photocatalytic system, named CNC-PDS has been proposed, which couples a metal-free carbon/g-C3N4 (CNC) photocatalyst with persulfate (PDS), and applied for efficient degradation of paracetamol (PCM) under simulated sunlight. The CNC-PDS system exhibited excellent photocatalytic capability, where the PCM was completely degraded in 40 min under simulated sunlight. The degradation rate of CNC-PDS system was 9.5 times compared with the g-C3N4 and PDS coupled systems. The CNC-PDS system can efficiently degrade other representative pollutants in neutral solutions, such as pharmaceuticals, endocrine disrupting compounds (EDCs), azo dyes. The excellent catalytic activity of CNC-PDS system should be ascribed to the two aspects: a) the increased light absorption range led to more photo-induced electron-hole pairs generation compared with the original g-C3N4. Meanwhile, the charge separation efficiency of the CNC photocatalyst was drastically enhanced which was proved by the results of PL and EIS analysis. These results represented the carbon/g-C3N4 might offer more e- to promote PDS activation. b) The introduction of CO and the improved specific surface area provided more active sites for PDS activation. In addition, the EPR analysis and quenching experiments indicated that O2.-, h+ and 1O2 were the main active species for PCM in the CNC-PDS system under simulated sunlight, and the contribution order was O2.->1O2>h+. The degradation pathways of PCM in the CNC-PDS system are proposed based on the results of HPLC-MS. The novel CNC-PDS photocatalytic system has provided a viable option for treatment of contaminated water by organic pollutants.


Assuntos
Carbono , Luz , Metais , Compostos Azo
3.
Proc Natl Acad Sci U S A ; 120(3): e2216241120, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36634139

RESUMO

Perturbative considerations account for the properties of conventional metals, including the range of temperatures where the transport scattering rate is 1/τtr = 2πλT, where λ is a dimensionless strength of the electron-phonon coupling. The fact that measured values satisfy λ ≲ 1 has been noted in the context of a possible "Planckian" bound on transport. However, since the electron-phonon scattering is quasielastic in this regime, no such Planckian considerations can be relevant. We present and analyze Monte Carlo results on the Holstein model which show that a different sort of bound is at play: a "stability" bound on λ consistent with metallic transport. We conjecture that a qualitatively similar bound on the strength of residual interactions, which is often stronger than Planckian, may apply to metals more generally.


Assuntos
Elétrons , Metais , Movimento Celular , Método de Monte Carlo , Fônons
5.
J Orthop Surg Res ; 18(1): 24, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36627685

RESUMO

BACKGROUND: The risks of metal release due to fretting and corrosion at the head-neck junction and consequent adverse local tissue reaction (ALTR) have concerns in metal-on-polyethylene (MoP) total hip arthroplasty (THA). Although trunnions have become thinner in diameter to increase the range of motion, it has remained unclear whether this change affects metal release and ALTR in vivo. This study aimed to investigate serum metal concentrations and the prevalence of ALTR in MoP THA with a 9/10-mm stem trunnion. PATIENTS AND METHODS: A consecutive series of 37 hips that underwent THA using MoP grafted with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) with a 9/10-mm trunnion stem were retrospectively reviewed. Serum metal levels were assessed and compared with those in MoP THA with a 10/12-mm trunnion stem. ALTR was diagnosed with serum metal levels and cross-sectional images. The factors associated with serum metal levels were also assessed. RESULTS: The median serum cobalt and chromium levels were 1.5 µg/L and 1.0 µg/L in the 9/10-mm group and 0.2 µg/L and 0.4 µg/L in the 10/12-mm group, respectively. ALTR was found in 5 hips of 3 patients. Revision surgery was performed in 4 hips, and all stem trunnions and femoral heads showed severe corrosion. Postoperative walking ability was associated with serum metal levels. CONCLUSION: It was found that a 9/10-mm stem trunnion with MoP grafted with PMPC had high risks of metal release in primary THA. Careful follow-up and cross-sectional imaging are needed to detect ALTR for early revision.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Humanos , Artroplastia de Quadril/efeitos adversos , Polietileno , Prótese de Quadril/efeitos adversos , Estudos Retrospectivos , Falha de Prótese , Metais , Cobalto , Reoperação/efeitos adversos , Desenho de Prótese
6.
Int J Mol Sci ; 24(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36614210

RESUMO

The present work describes an efficient reaction of electrochemical phosphorylation of phenylacetylene controlled by the composition of catalytic nanoparticles based on non-noble-metals. The sought-after products are produced via the simple synthetic protocol based on room temperature, atom-economical reactions, and silica nanoparticles (SNs) loaded by one or two d-metal ions as nanocatalysts. The redox and catalytic properties of SNs can be tuned with a range of parameters, such as compositions of the bimetallic systems, their preparation method, and morphology. Monometallic SNs give phosphorylated acetylene with retention of the triple bond, and bimetallic SNs give a bis-phosphorylation product. This is the first example of acetylene and phosphine oxide C-H/P-H coupling with a regenerable and recyclable catalyst.


Assuntos
Nanopartículas , Óxidos , Metais/química , Alcinos
7.
Molecules ; 28(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36615548

RESUMO

This study processes a facile and green approach for the Markovnikov-selective hydroamination of styrene with naphthylamine through irradiation with UV LED light (365 nm) via an electron donor-acceptor complexation between naphthylamines and oxygen in situ. This protocol showcases the synthetic potential for aerobic C-N bond formation without using a metal catalyst and photosensitizer. Three naphthylamines were examined and afforded desired C-N bond formation product in moderate yield.


Assuntos
Elétrons , Estireno , Estireno/química , Aminas/química , Aminação , Metais
8.
Chemosphere ; 316: 137797, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36634713

RESUMO

Transition metal doped WO3 mixed oxides (named as W-M-O, M = Nb, Fe, Cr, Cu, Ti or Sn, respectively) with high structure stability were synthesized by modified sol-gel method using citric acid as organic crosslinking agent, and were evaluated for catalytic elimination of low-concentration toluene, monochlorobenzene and 1,2-dichloroethance with high toxicity and relatively stable molecule structure, as the typical examples for the pollutants of various volatile organic compounds (VOCs). Results of the structure-property-performance relationship research showed that mesoporous structure and nanocrystalline/amorphous state were formed, and binary metal components were dispersed into each other, which contributed to promoting the metal/metal electron interaction and adjusting the physicochemical properties of mixed metal oxides. The sequence of apparent catalytic activity for toluene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Cu-O>W-Ti-O>W-Sn-O>WO3, and the sequence for monochlorobenzene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Ti-O>W-Cu-O>W-Sn-O>WO3. There existed cooperative catalytic effect: mesopore and surface acid sites of catalysts facilitated adsorption, activation and breakage of the C-X bond, and then redox sites of catalysts promoted deep oxidation of a series of reaction intermediates to transform into CO2 and H2O. Especially, the optimized W-Nb-O catalyst deserved more attention, since it represented remarkable catalytic activity, selectivity and durability for three typical VOCs degradation along with good resistance to water vapor and corrosion of HCl.


Assuntos
Poluentes Ambientais , Elementos de Transição , Óxidos/química , Clorobenzenos , Oxirredução , Metais/química , Catálise , Tolueno/química
9.
Nat Commun ; 14(1): 385, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36693843

RESUMO

The Zrt-/Irt-like protein (ZIP) family consists of ubiquitously expressed divalent metal transporters critically involved in maintaining systemic and cellular homeostasis of zinc, iron, and manganese. Here, we present a study on a prokaryotic ZIP from Bordetella bronchiseptica (BbZIP) by combining structural biology, evolutionary covariance, computational modeling, and a variety of biochemical assays to tackle the issue of the transport mechanism which has not been established for the ZIP family. The apo state structure in an inward-facing conformation revealed a disassembled transport site, altered inter-helical interactions, and importantly, a rigid body movement of a 4-transmembrane helix (TM) bundle relative to the other TMs. The computationally generated and biochemically validated outward-facing conformation model revealed a slide of the 4-TM bundle, which carries the transport site(s), by approximately 8 Å toward the extracellular side against the static TMs which mediate dimerization. These findings allow us to conclude that BbZIP is an elevator-type transporter.


Assuntos
Proteínas de Bactérias , Proteínas de Transporte de Cátions , Proteínas de Bactérias/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Metais/metabolismo , Zinco/metabolismo , Ferro/metabolismo
10.
Dalton Trans ; 52(4): 1021-1029, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36601998

RESUMO

Low-dimensional organic-inorganic hybrid halides, as an important branch of metal halide materials, have attracted much attention due to their excellent photoelectric properties. Herein, we designed one new hybrid cadmium chloride [C5H14NO]CdCl3 based on combinations of the d10 metal cation (Cd2+) and choline chloride molecules. [C5H14NO]CdCl3 single crystals belong to the orthorhombic Pna21 space group and show a one-dimensional (1D) structure with distorted [CdCl5O]5- octahedra. The second harmonic generation (SHG) response of [C5H14NO]CdCl3 exhibits an intensity of approximately 0.4 × KDP. Moreover, the photoluminescence properties of the [C5H14NO]CdCl3 crystal are activated by doping with Sn2+ ions having stereochemically active lone pair 5s2 electrons. Under UV excitation conditions, bright greenish-yellow light emission can be observed, and the quantum efficiency (PLQY) is as high as 91.27%. The luminescence mechanism is revealed by combining the results of temperature dependent luminescence and density functional theory (DFT) calculation. This work can serve as a guide for the design and synthesis of emerging optical materials.


Assuntos
Compostos Inorgânicos , Metais , Elétrons , Colina , Luminescência
11.
Chem Commun (Camb) ; 59(8): 1042-1045, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36602269

RESUMO

Two multichromophoric FRET macrocycles M1 [1+1] and M2 [2+2] with red emission (λem ∼ 721 nm) composed of perylenediimide (PDI) as the energy donor and aza-BODIPY (ABDP) as the energy acceptor were synthesized by click reaction in a metal-free fashion. M1 and M2 exhibited distinct reversible ratiometric temperature responsive emission with temperature sensitivities of 0.09-0.14% °C-1 and owing to the redox active chromophores, they showed solution phase redox responsive reversible colour changes.


Assuntos
Transferência Ressonante de Energia de Fluorescência , Imidas , Metais
12.
Chem Commun (Camb) ; 59(8): 1066-1069, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36606800

RESUMO

A Li6PS5Cl-rich composite is prepared using a PEG-borate ester solid-state polymer electrolyte (BSPE). BSPE is a highly accessible compound with high ionic conductivity and excellent electrochemical stability against Li metal. Thereby, the stability of the Li6PS5Cl-rich composite with BSPE improved significantly.


Assuntos
Boratos , Eletrólitos , Íons , Lítio , Metais , Ésteres , Polímeros
13.
Inorg Chem ; 62(3): 1226-1233, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36622297

RESUMO

Inspired by the unique catalytic properties of enzymes, numerous biomimetic catalysts have been developed with the intention to realize activation of unreactive reactants under mild conditions; however, the requirement of harsh activation conditions heavily deters their practical applications. We report herein a porous metal silicate (PMS) material PMS-12 that consists of redox-active copper and vanadium metal sites, which exhibits similar catalytic behaviors of enzymes by synergistically activating different reactant molecules and generating local redox potential to facilitate electron and charge transfer, demonstrating the highest catalytic efficiency for aerobic oxidation of phenols to produce highly value-added benzoquinones under mild conditions. Therefore, this work paves a practically applicable strategy for developing high-performance heterogeneous catalysts, which could activate unreactive reactant molecules to produce highly value-added chemicals under mild conditions.


Assuntos
Metais , Fenóis , Fenóis/química , Porosidade , Oxirredução , Cobre/química
14.
Inorg Chem ; 62(3): 1210-1217, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36626658

RESUMO

Metal-organic frameworks (MOFs) have attracted significant attention over the past 2 decades due to their wide applicability as functional materials. However, targeted synthesis of novel MOFs remains problematic as their formation mechanisms are poorly understood, which forces us to rely on serendipity in the synthesis of novel MOFs. Here, we demonstrate a workflow employing the artificial force induced reaction (AFIR) method to investigate the self-assembly process of the node of the SIFSIX-3-Zn MOF, [Zn(pyz)4(SiF6)2]2- (pyz = pyrazine), in an automated manner. The workflow encompassing AFIR calculations, generation of extensive reaction path networks, propagation simulations of intermediates, and further refinements of identified formation pathways showed that the nodal structure can form through multiple competing pathways involving interconvertible intermediates. This finding provides a plausible rationale for the stochastic multistage processes believed to be key in MOF formation. Furthermore, this work represents the first application of an automated reaction mechanism discovery method to a MOF system using a general workflow that is applicable to study the formation of other MOF motifs as well.


Assuntos
Estruturas Metalorgânicas , Metais , Pirazinas , Zinco
15.
Biomed Phys Eng Express ; 9(2)2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36645907

RESUMO

We propose a technique for metal artefact reduction in digital tomosynthesis reconstruction. Although the problem was addressed earlier in the literature, we suggest another approach, which is, in our opinion, simpler, and easier to implement. It is a two-stage algorithm. At the first stage, attenuation images are segmented by decomposing their intensity distributions into gaussian-like components. Statistical information contained in each component is used for pixel classification. Components corresponding to metallic objects are identified, and a pixel threshold value separating regions occupied by metal objects from the rest of the image is found. Based on this value, at the second stage, a smooth mapping of image intensity is applied. This makes dense regions transparent, resulting in the artefact reduction in reconstruction. The methodology is demonstrated by several examples.


Assuntos
Artefatos , Tomografia Computadorizada por Raios X , Tomografia Computadorizada por Raios X/métodos , Radiografia , Algoritmos , Metais
16.
Int J Mol Sci ; 24(2)2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36674772

RESUMO

Biometals are all metal ions that are essential for all living organisms. About 40% of all enzymes with known structures require biometals to function correctly. The main target of damage by biometals is the central nervous system (CNS). Biometal dysregulation (metal deficiency or overload) is related to pathological processes. Chronic occupational and environmental exposure to biometals, including iron and copper, is related to an increased risk of developing Parkinson's disease (PD). Indeed, biometals have been shown to induce a dopaminergic neuronal loss in the substantia nigra. Although the etiology of PD is still unknown, oxidative stress dysregulation, mitochondrial dysfunction, and inhibition of both the ubiquitin-proteasome system (UPS) and autophagy are related to dopaminergic neuronal death. Herein, we addressed the involvement of redox-active biometals, iron, and copper, as oxidative stress and neuronal death inducers, as well as the current metal chelation-based therapy in PD.


Assuntos
Doença de Parkinson , Oligoelementos , Humanos , Doença de Parkinson/patologia , Cobre , Metais , Ferro , Estresse Oxidativo , Oxirredução , Neurônios Dopaminérgicos/patologia , Quelantes/farmacologia , Quelantes/uso terapêutico
17.
Molecules ; 28(2)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36677845

RESUMO

In recent years, the importance of "environmentally friendly manufacturing" has been increasing toward the establishment of a resource-recycling society. In organic synthesis, as well, it is becoming increasingly important to develop new synthetic strategies with resource conservation and the recycling of elemental resources in mind, rather than just only synthesis. Many studies on the construction of frameworks of functional molecules using ionic reactions and transition-metal-catalyzed reactions have been reported, but most of them have focused on the formation of carbon-carbon bonds. However, it is essential to introduce appropriate functional groups at appropriate positions in molecules in order for the molecules to express their functions, and furthermore, the highly selective preparation of multiple functional groups is considered important for the creation of new functional molecules. In this review, we focus on radical reactions with high functional group selectivity and overview the recent progress in practical methods for the simultaneous introduction of multiple functional groups and propose future synthetic strategies that emphasize the recycling of elemental resources and environmental friendliness.


Assuntos
Elementos de Transição , Elementos de Transição/química , Metais , Carbono/química , Técnicas de Química Sintética
18.
Sci Rep ; 13(1): 1212, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681770

RESUMO

The replacement of metals in catalytic processes is highly demanded to improve sustainability and economic growth. Poor stability and metal leaching are the main drawbacks of metal-based catalytic reactions. This work represented the use of nitrogen and sulfur-co-doped mesoporous carbon material ((N, S)-MPC) as a metal-free catalyst for the degradation of 4-nitrophenol (4-NP) as a priority pollutant announced by the Environmental Protection Agency through the persulfate-based advanced oxidation process. A low amount of (N, S)-MPC catalyst (0.3 g/L) exhibited superior performance for the degradation of 4-NP within 3 h at room temperature and unadjusted pH. The COD removal was calculated to be 76% using (N, S)-MPC catalyst. Interestingly, the degradations kinetics of 4-NP followed the zero-order kinetics with the rate constant of 0.505 min-1. The radical quenching experiment was accomplished to investigate the activation pathway of degradation. A real sample from an oil and gas company was treated with the (N, S)-MPC catalyst, which showed excellent total decontamination of 61%. The recyclability and stability of the catalyst have been evaluated for three runs. Owing to the obvious benefits such as high efficiency, metal-free nature, and recyclability, the presented catalyst can improve pollutant removal from aqueous media and practical environmental remediation.


Assuntos
Carbono , Poluentes Ambientais , Nitrogênio , Porosidade , Metais , Enxofre , Estresse Oxidativo
19.
Chemosphere ; 315: 137692, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36596328

RESUMO

Metal pollution has raised negative impact on microbes, but little is known about the distribution and co-occurrence pattern of bacterial, fungal and archaeal communities along the soil profiles at multiple metal contamination sites. Here, we characterized the variations of metal concentrations and microbial communities with soil depth along five deep bores at the Tanghe Sewage Reservoir, a typical metal contamination area on the North China Plain. Co, Cd, Mg, Se, and Li were identified as the major contaminants in this area, and the pollution load index was 1.88, 1.54 and 1.62 in the shallow layer (0-0.6 m), deep layer (>2.0 m) and middle layer (0.6-2.0 m), respectively. The diversities and compositions of bacterial, archaeal and fungal communities varied significantly along the soil profiles. Deterministic process played a crucial role in shaping the difference of microbial community compositions among different soil layers, in which metal levels contributed more than soil physiochemical parameters. Furthermore, the interspecific co-occurrence network was most complex in the middle layer, indicating that metal pollution could decrease microbial network complexity. Bacterial keystone species in the co-occurrence networks showed both positive and negative correlations with polluted metals, whereas most archaeal and fungal keystone species were negatively related to multiple metals. These findings increased our understanding of distribution patterns, co-occurrence networks and environmental drivers of microbial communities in metal pollution soils.


Assuntos
Micobioma , Poluentes do Solo , Archaea , Solo/química , Poluentes do Solo/análise , Bactérias , Metais/farmacologia , Microbiologia do Solo
20.
J Chromatogr A ; 1689: 463772, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36610186

RESUMO

Algae toxins pose a severe threat to human health all over the world. In this study, magnetic metal/nitrogen-doped carbon nanotubes (M-NCNTs) were facilely synthesized based on one-step carbonization and applied for magnetic solid-phase extraction of okadaic acid (OA) from seawater followed by high performance liquid chromatographic tandem mass spectrometry (HPLC-MS/MS) analyses. Differences in the physicochemical properties of the three prepared materials (Fe/Co/Ni-NCNTs) were investigated to confirm the best extraction material. Among them, Ni-NCNTs demonstrated a faster extraction rate (10 min) and higher adsorption capacity (223.5 mg g-1), mainly due to the higher specific surface area, suitable pore structure and more abundant pyridine nitrogen ring. Under the optimal conditions, the calibration curve was linear over the range (1.0-800.0 pg mL-1) with good determination coefficients (R) of 0.9992. The limit of detection (LOD) obtained in multiple replicates was 0.4 pg mL-1. Three seawater samples were measured by the developed method, 12.3 pg mL-1 of OA was detected with a satisfying recovery (88.6%-106.7%) and acceptable repeatability (RSD ≤ 4.8%, n = 6). The results demonstrate that M-NCNTs materials are a promising candidate for magnetic solid-phase extraction. Benefiting from its high extraction and interference resistance, the established analytical method is expected to be extended to detect other marine environmental pollutions.


Assuntos
Nanotubos de Carbono , Humanos , Ácido Okadáico/análise , Nanotubos de Carbono/química , Espectrometria de Massas em Tandem/métodos , Nitrogênio , Água do Mar/química , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão , Metais , Fenômenos Magnéticos
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