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1.
Food Chem ; 319: 126432, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32172045

RESUMO

The main aim of the present study was the measurement of nickel metal ion in the real samples of crab, oyster and rice by the designed magnetic nano adsorbent silk fibroin-EDTA ligand (SF-Fe3O4-EDTA). Due to the structure of silk fibroin (possessing lots of functional groups which are suitable for attachment of ligands and high surface area), it was used in the structure of fabricated nano-adsorbent. To follow the fabrication processes of the magnetic nano-adsorbent, different techniques of fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Visible), vibrating sample magnetometer (VSM), and field emission scanning electron microscopy (FE-SEM) were used. The optimization processes were performed with the chemometric method of response surface modeling with sufficient accuracy and precision. Using this chemometric method, the optimum values of pH, absorption time, the concentration of nano-adsorbent and temperature were calculated to be 6, 21 min, 4 mg L-1 and 28 °C, respectively. Due to the magnetic nature of the constructed nano-adsorbent, a magnet bar was used to separate the nano-adsorbent from the solution and then inject to the furnace atomic absorption device. Using the magnetic nano-adsorbent of silk fibroin-EDTA ligand and furnace atomic absorption a detection limit of 0.0017 µg L-1 and a linear range of 0.0030-5.0 µg L-1 for determination of nickel metal ion were obtained. The determination of nickel metal ion in the crab tissue, oyster tissue and rice samples were performed and the obtained results revealed the successful applicability of the designed method for determination of nickel metal ion in the real samples.


Assuntos
Braquiúros/química , Fibroínas/química , Níquel/análise , Oryza/química , Frutos do Mar , Animais , Ácido Edético/química , Ligantes , Limite de Detecção , Magnetismo , Imãs , Espectrofotometria Atômica
2.
Int J Comput Dent ; 23(1): 39-48, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32207460

RESUMO

BACKGROUND: The Dental Motion Decoder system (DMS-System) is a medical device based on magnetic field technology that records mandible movements. The data can be used to program an articulator or can be directly processed over a computer-aided design (CAD) interface. The present study aimed to assess the reproducibility of this system in vitro and in vivo. MATERIAL AND METHODS: Protrusive and laterotrusive movements were simulated in vitro using an articulator (SAM SE) (Group M) and in vivo (Group P) on one test individual. Measurements were carried out in two ways: 1) Measurements were taken after initializing and referencing the system using the reference points (RPs) once, followed by 30 protrusive and laterotrusive movements (M1 and P1); and 2) Thirty individual measurements were recorded using the RPs before each measurement (M2 and P2). Values for the sagittal condylar path inclination angle (sCPIA) and the Bennett angle (BA) were exported and analyzed. The reproducibility of the system was evaluated using the standard deviations (SDs) of the measurement series (sCPIA and BA for M1, M2, P1, and P2). RESULTS: In vitro tests M1 (SD: sCPIA = 0.08 degrees; BA = 0.06 degrees) and M2 (SD: sCPIA = 0.26 degrees; BA = 0.11 degrees) showed significantly higher reproducibility (P < 0.001) compared with the in vivo measurements P1 (SD: sCPIA = 0.61 degrees; BA = 0.45 degrees) and P2 (SD: sCPIA = 1.4 degrees; BA = 0.65 degrees). CONCLUSION: Within the limitations of the present study, the deviation in vitro, representing the reproducibility of the DMD-System, is smaller than the biologic variance observed in vivo. Therefore, reliable measurements under clinical conditions can be assumed.


Assuntos
Articuladores Dentários , Côndilo Mandibular , Humanos , Registro da Relação Maxilomandibular , Imãs , Movimento , Reprodutibilidade dos Testes
3.
Chemosphere ; 248: 126042, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32032878

RESUMO

For the practical capture of heavy metal ions from wastewater, fabricating environmental friendly adsorbents with high stability and super adsorption capacity are pursuing issue. In this work, we develop magnetic supramolecular polymer composites (M-SMP) by using a simple two-step hydrothermal method. Systematical characterizations of morphological, chemical and magnetic properties were conducted to confirm the formation of M-SMP composites. The resulting M-SMP composites were applied to remove Pb(II) from aqueous solution and from real battery wastewater, and easy separation was achieved using a permanent magnet. By investigating the effects of various parameters, we optimized their operating condition for Pb(II) adsorption by the M-SMP. The uptake of Pb(II) onto M-SMP fitted well the pseudo-second-order and Langmuir isotherm models, and favourable thermodynamics showed a spontaneous endothermic process. The SMP endowed M-SMP with ultrahigh adsorption capacity for Pb(II) (946.9 mg g-1 at pH = 4.0, T = 298 K), remarkable selectivity, satisfactory stability and desirable recyclability. In Pb-contaminated lead-acid battery industrial wastewater, the concentration of Pb(II) declined from 18.070 mg L-1 to 0.091 mg L-1, which meets the current emission standard for the battery industry. These merits, combined with simple synthesis and convenient separation, make M-SMP an outstanding scavenger for the elimination of industrial Pb(II) wastewater.


Assuntos
Chumbo/química , Polímeros/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Fontes de Energia Elétrica , Concentração de Íons de Hidrogênio , Cinética , Chumbo/análise , Fenômenos Magnéticos , Magnetismo , Imãs , Metais Pesados , Termodinâmica , Águas Residuárias/química , Água/química , Poluentes Químicos da Água/análise
4.
Chemosphere ; 244: 125457, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32050323

RESUMO

The wide range of applications of rare earth elements (REE) is leading to their occurrence in worldwide aquatic environments. Among the most popular REE is Neodymium (Nd), being widely used in permanent magnets, lasers, and glass additives. Neodymium-iron-boron (NdFeB) magnets is the main application of Nd since they are used in electric motors, hard disk drives, speakers and generators for wind turbines. Recent studies have already evaluated the toxic potential of different REE, but no information is available on the effects of Nd towards marine bivalves. Thus, the present study evaluated the biochemical alterations caused by Nd in the mussel Mytilus galloprovincialis exposed to this element for 28 days. The results obtained clearly demonstrated that Nd was accumulated by mussels, leading to mussel's metabolic capacity increase and GLY expenditure, in an attempt to fuel up defense mechanisms. Antioxidant and biotransformation defenses were insufficient in the elimination of ROS excess, resulting from the presence of Nd and increased electron transport system activity, which caused cellular damages (measured by lipid peroxidation) and loss of redox balance (assessed by the ratio between reduced and oxidized glutathione). The results obtained clearly highlight the potential toxicity of REEs and, in particular of Nd, with impacts at cellular level, which may have consequences in mussel's survival, growth and reproduction, affecting mussel's population.


Assuntos
Imãs/química , Metais Terras Raras/toxicidade , Mytilus/efeitos dos fármacos , Neodímio/toxicidade , Animais , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Metais Terras Raras/farmacologia , Mytilus/metabolismo , Oxirredução , Poluentes Químicos da Água/toxicidade
5.
Quintessence Int ; 51(2): 152-154, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31942575

RESUMO

The health risks associated with aspiration and ingestion of foreign bodies in children are well known. The increased availability of magnetic toys have added to these risks. A 7-year-old girl presented at the Department of Maxillofacial and Oral Surgery at the University of Pretoria Oral and Dental Hospital with a complaint of pain under the tongue. Examination revealed that magnetic balls had been lodged on either side of the lingual frenum. The patient experienced pain and was unable to dislodge the magnets. This case report documents patient presentation and management and concludes with a brief discussion of potential complications associated with the oral intake of magnets. Though multiple cases documenting the complications associated with ingestion of magnets have been reported, reports of primary oral complications are scant. This case contributes to existing evidence for the dangers associated with high strength magnets used as toys by children.


Assuntos
Corpos Estranhos , Freio Lingual , Anquiloglossia , Criança , Feminino , Humanos , Fenômenos Magnéticos , Imãs
7.
Talanta ; 209: 120542, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31891994

RESUMO

Several magnetic ionic liquids (MILs), [P6,6,6,14+][FeCl4-], [P6,6,6,14+]2[MnCl42-], [P6,6,6,14+]2[CoCl42-] and [P6,6,6,14+]2[NiCl42-] were synthesized and applied for the extraction of six estrogens (estrone, estradiol, 17-α-hydroxyprogesterone, chloromadinone 17-acetate, megestrol 17-acetate and medroxyprogesterone 17-acetate) in dispersive liquid-liquid microextraction (DLLME). The [CoCl42-]-based MIL was selected as extraction solvent for the separation and concentration of estrogens from milk and cosmetics due to its visual recognition, no sign of hydrolysis, solution acquisition easier and the highest extraction capacity. In addition, the [CoCl42-]-based MIL with low UV absorbance allows direct analysis of the extraction solvent by HPLC-UV. The influence of the mass of MIL, extraction time, salt concentration, and the pH of the sample solution was investigated to obtain optimized extraction efficiency. Besides, extraction conditions including salt concentration, mass of MIL and extraction time were further optimized by the Box-Behnken design through the response surface method. Under optimized conditions, the limits of detection (LODs) of all estrogens were ranged from 5 ng mL-1 to 15 ng mL-1. The recoveries ranging from 98.5% to 109.3% in milk and from 96.3% to 111.4% in cosmetics were also studied, respectively. Furthermore, the proposed method were statistically compared with the reported conventional IL-DLLME method and the National standard methods of food safety and cosmetics. The experimental results showed that the functionalized MIL could successfully applied for extraction, separation and pretreatment of estrogens in milk and cosmetics.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cosméticos/análise , Estrogênios/análise , Líquidos Iônicos/química , Leite/química , Animais , Cromatografia Líquida de Alta Pressão/economia , Limite de Detecção , Imãs/química , Fatores de Tempo
8.
Talanta ; 209: 120555, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31892075

RESUMO

A novel magnetic surface molecular imprinted polymers with 2, 4, 6-trisacrylamido-3, 5-triazine (TAT) as a functional monomer was successfully synthesized and used for the enrichment and determination of zearalenone. The molecular imprinting is reported herein at first time for application of zearalenone in wheat. The magnetic imprinted materials possessed excellent magnetism and uniform appearance, which were characterized by fourier transform infared spectroscopy and transmission electron microscope. The results proved the magnetic molecular imprinted polymers was successfully prepared. The magnetic molecular imprinted polymers exhibited satisfactory sensitivity, stability and potential reusability. The binding affinity was investigated by selectivity experiment, which possessed high selectivity. To obtain the optimal application conditions, the amount of adsorption, extraction time, elution solvent and time were optimized. The limited detection of zearalenone was 0.55 ng g-1 and the recoveries of zearalenone were 92.1-96.0%. The relative standard deviation was lower than 5.4%. This indicated that a simple, efficient and low-cost method was established and successfully applied in spiked wheat sample.


Assuntos
Imãs/química , Impressão Molecular/métodos , Polímeros/química , Triticum/química , Zearalenona/análise , Acrilamidas/química , Adsorção , Cromatografia Líquida de Alta Pressão/métodos , Triazinas/química , Zearalenona/isolamento & purificação
9.
Biomed Chromatogr ; 34(2): e4763, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31770450

RESUMO

Target biomolecule-immobilized magnetic beads could be used as a powerful tool for screening active compounds present in natural products. Low damage rates of the target proteins, associated with the availability of diverse automated online approaches for analysis, make it a valuable tool for affinity studies. RAW264.7 cells (a kind of murine macrophage cell line) were used in this study. These cellular membranes were immobilized onto the surface of MBs and were used for screening the active compounds of Polygonatum sibiricum. Combining this technique with HPLC led to the identification of an active compound and its biological activity was confirmed. This is the first report establishing the use of RAW264.7 cellular membrane-coated magnetic bead fishing followed by HPLC analysis for screening active compounds from natural products.


Assuntos
Membrana Celular/química , Cromatografia Líquida de Alta Pressão/métodos , Imãs/química , Extratos Vegetais , Polygonatum/química , Animais , Membrana Celular/metabolismo , Descoberta de Drogas , Camundongos , Compostos Fitoquímicos , Extratos Vegetais/análise , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Células RAW 264.7
10.
J Surg Res ; 245: 249-256, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31421370

RESUMO

BACKGROUND: Technical improvement of gastrojejunostomy is critical in bariatric and metabolic surgery. In this study, a novel magnetic compression approach for gastrojejunostomy was evaluated. MATERIALS AND METHODS: Both cylindrical and rectangular magnets were used in rabbits, and the magnets were named according to their location. All the magnets were perorally introduced into the stomach. The position of the jejunal magnet was controlled by a connecting line. When the jejunal magnet spontaneously entered the jejunum, the gastric magnet was introduced into the stomach. An extracorporeal magnet was used to guide these two magnets together, and the magnet pair was left to create a side-to-side anastomosis. The state of the animals and extrusion time of the magnets were observed. The anastomoses were evaluated by burst pressure and histology. RESULTS: Gastrojejunostomy was successfully established in all animals. Cylindrical and rectangular magnets spontaneously entered the jejunum through the pylorus within 2.4 ± 0.5 and 6.0 ± 0.8 d, respectively (P < 0.01). The cylindrical and rectangular magnet pairs fell off within 15.3 ± 0.8 and 11.9 ± 1.1 d, respectively (P < 0.01). The burst pressures were statistically similar between the two types of magnets (P > 0.05). Histological examination showed sealed anastomoses with mild inflammation of the mucosa and fibrosis within the submucosa. CONCLUSIONS: The feasibility and efficacy of establishing gastrojejunostomy by guidewire introduction of magnets, which were guided together with an extracorporeal magnet, were confirmed in rabbits. In humans, with the clinical use of this procedure, surgery would be greatly simplified.


Assuntos
Derivação Gástrica/instrumentação , Gastrostomia/instrumentação , Jejunostomia/instrumentação , Imãs , Animais , Desenho de Equipamento , Estudos de Viabilidade , Feminino , Derivação Gástrica/efeitos adversos , Derivação Gástrica/métodos , Gastrostomia/efeitos adversos , Gastrostomia/métodos , Jejunostomia/efeitos adversos , Jejunostomia/métodos , Masculino , Modelos Animais , Pressão , Coelhos
11.
Talanta ; 207: 120300, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594586

RESUMO

A "signal-on" chemiluminescence biosensor was established for detecting thrombin. The thrombin aptamer1-functionalized magnetic sodium alginate (Malg-Apt1) hydrogel was synthesized by physical interaction between sodium alginate and Ca2+, and it was used in the biosensor for separating and enriching thrombin. Ethylenediamine tetraacetic acid (EDTA) was used to chelate with Ca2+ to dissolve the hydrogel and release thrombin. A metalloporphyrinic metal-organic framework nanosheet, named as Cu-TCPP(Co) MOFs, was prepared as signal amplification strategy. Cu-TCPP(Co) MOFs/Au-ssDNA (ssDNA: single-strand DNA) was synthesized for controllable further amplification of chemiluminescent signal. The thrombin aptamer2-functionalized magnetic carbon nanotubes (MCNTs-Apt2) were used as a matrix, and Cu-TCPP(Co) MOFs/Au-ssDNA was adsorbed on the MCNTs by the complementary pairing of the partial bases between ssDNA and Apt2. Compared with ssDNA, Apt2 has a stronger interaction with thrombin. Therefore, thrombin can trigger the release of Cu-TCPP(Co) MOFs/Au-ssDNA to achieve signal amplification. Under the optimal conditions, the biosensor could detect thrombin as low as 2.178 × 10-13 mol/L with the range from 8.934 × 10-13 to 5.956 × 10-10 mol/L and exhibited excellent selectively. Moreover, the "signal-on" chemiluminescence biosensor showed potential application for the detection of thrombin in body fluids.


Assuntos
Alginatos/química , Técnicas Biossensoriais/métodos , DNA de Cadeia Simples/química , Hidrogéis/química , Estruturas Metalorgânicas/química , Nanotubos de Carbono/química , Trombina/análise , Adsorção , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Sequência de Bases , DNA de Cadeia Simples/genética , Medições Luminescentes , Imãs/química , Modelos Moleculares , Conformação Molecular , Porfirinas/química , Trombina/metabolismo
12.
Talanta ; 207: 120290, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594607

RESUMO

Human T-lymphotropic virus type II (HTLV-II) is a crucial retrovirus that is closely associated with a variety of human diseases. Herein, an ultrasensitive fluorescent HTLV-II DNA detection strategy was developed for the first time based on magnetic nanoparticles (MNPs) and atom transfer radical polymerization (ATRP) amplification. In this approach, hairpin DNA probes (pDNA) labelled with 5' thiol and 3' azide group terminally were immobilized on amino group modified MNPs surface through sulfo-N-succinimidyl-4-maleimidobutyrate sodium salt (sulfo-GMBS) cross-linkers. In the presence of target DNAs (tDNA), pDNA hybridized with tDNA to form double-stranded DNA, and therefore its azide group was away from the MNPs surface. Subsequently, to initiate ATRP reaction, initiators were introduced into the pDNA by a Cu (I)-catalyzed alkyne-azide cycloaddition (CuAAC). Then, large numbers of 9-anthracenylmethyl methacrylate polymer (pAMMA) were successfully labelled on the MNPs surface, resulting in significant amplification of the fluorescence signal. Under optimized conditions, the fluorescence signal was proportional to the logarithm of the concentration of tDNA over the range from 1 fM to 1 nM, with a detection limit of 0.22 fM. Moreover, this strategy was capable of discriminating mismatched bases and detecting HTLV-II DNA in human serum samples. By virtue of the high sensitivity, selectivity, simplicity and economy, this ultrasensitive biosensor demonstrates great potential for biomedical research and early clinical diagnosis.


Assuntos
Técnicas Biossensoriais/métodos , DNA Viral/análise , Vírus Linfotrópico T Tipo 2 Humano/genética , Limite de Detecção , Imãs/química , Nanopartículas/química , Polimerização , DNA Viral/sangue , DNA Viral/química , Humanos , Hibridização de Ácido Nucleico , Espectrometria de Fluorescência
13.
Talanta ; 207: 120284, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594616

RESUMO

Magnetic carbon nanotubes (CNTs) with encapsulated Co nanoparticles (Co@CNTs), was synthesized by exploiting the one-step pyrolysis strategy using ZIF-67 as template. The as-synthesized Co@CNTs is provided with the nanopores, a large specific surface area, and strong magnetic response. The obtained Co@CNTs was used as magnetic solid-phase extraction adsorbents to extract two profens including flurbiprofen and ketoprofen. The parameters of extraction efficiency, involving extraction time, sample solution volume, ionic strength, pH and the conditions of desorption efficiency, were optimized in detail. After determined by high-performance liquid chromatography-ultraviolet (HPLC-UV), the results evinced that Co@CNTs showed a high extraction efficiency with high enrichment factors of 832 and 672. The good linear range of both flurbiprofen and ketoprofen were all 5.0-1000 ng L-1, with the limit of detection were 0.60 ng L-1 and 0.70 ng L-1, respectively. Furthermore, a valid method for the extraction of flurbiprofen and ketoprofen from human serum was established. The spiking recoveries of two profens were between 86.74% and 97.22%, and the relative standard deviation was less than 6.55%. Co@CNTs can be repeatedly used at least 10 times, indicating its excellent regeneration and reusability. The results demonstrated that the Co@CNTs materials exhibits high enrichment ability and extraction efficiency, playing great promise in MSPE.


Assuntos
Flurbiprofeno/isolamento & purificação , Cetoprofeno/isolamento & purificação , Imãs/química , Nanotubos de Carbono/química , Compostos Organometálicos/química , Extração em Fase Sólida/métodos , Adsorção , Cobalto/química , Flurbiprofeno/sangue , Flurbiprofeno/química , Humanos , Imidazóis/química , Cetoprofeno/sangue , Cetoprofeno/química , Nanopartículas Metálicas/química
14.
Carbohydr Polym ; 229: 115512, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826502

RESUMO

In recent decades, increased industrial activities have led to the release of various pollutants, such as toxic heavy metals, inorganic anions, and organics. It is imperative but challenging to develop an eco-friendly treatment technology with easy operation, low cost, and high efficiency. Here, we describe a design of magnetic purifier, which has biomass-based structure by blending attapulgite/chitosan (ATP/CS) composite with bacterial cellulose nanofibrils (BCNs). Compared to similar materials reported previously, our product exhibited efficient adsorption capacities towards various metal ions including Pb2+, Cu2+, and Cr6+, and anionic organic dyes including Congo red. The adsorption process could be well fitted by Langmuir isotherm and pseudo-second order equation. Additionally, the adsorption capacity only decreased less than 8% after five adsorption-desorption cycles. We expect our design will inspire more efforts to build a multifunctional water purifier with simple operation, and hopefully effectively remove pollutants from wastewater in future practical applications.


Assuntos
Bactérias/química , Celulose/química , Corantes/química , Compostos de Magnésio/química , Imãs/química , Metais Pesados/química , Compostos de Silício/química , Poluentes Químicos da Água/química , Adsorção , Corantes/isolamento & purificação , Água Doce/química , Cinética , Metais Pesados/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
15.
Otolaryngol Clin North Am ; 53(1): 57-71, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31685238

RESUMO

Over the past 50 years, incredible progress has been made with implantable devices. Management can become complex, as unique issues arise with interaction of these devices with other devices and technologies. The cochlear implant (CI) is the most commonly implanted device in the head and neck. Because of its internal magnet, CIs can interfere with MRI, causing imaging artifacts, pain, and device complications. Other implants demonstrate similar issues with imaging and co-implantation. This article provides an overview of special considerations regarding neurostimulation devices within the head and neck. We focus on interactions between implantable devices and other technologies or devices.


Assuntos
Implantes Cocleares , Imãs , Segurança , Artefatos , Humanos , Imagem por Ressonância Magnética
16.
Biosens Bioelectron ; 148: 111819, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31678825

RESUMO

In this paper, a sensor based on a magnetic surface molecularly imprinted membrane (MMIP) was prepared for the highly sensitive and selective determination of acetaminophen (AP). Before the experiment, the appropriate functional monomers and solvents required for the polymer were screened, and the molecular electrostatic potentials (MEPs) were calculated by the DFT/B3LYP/6-31 + G method. MMIP with high recognition of AP was synthesized based on Fe3O4@SiO2nanoparticles (NPs) with excellent core-shell structure. Next, a carbon paste electrode (CPE) was filled with a piece of neodymium-iron-boron magnet to make magnetic electrode (MCPE), and MMIP/MCPE sensor was obtained by attaching a printed polymer to the surface of the electrode under the strong magnetic. Due to the stable molecular structure of the electrode surface, the sensor is highly effective and accurate for detection of AP using DPV. The DPV response of the sensor exhibited a linear dependence on the concentration of AP from 6 × 10-8 to 5 × 10-5 mol L-1 and 5 × 10-5 to 2 × 10-4 mol L-1, with a detection limit based on the lower linear range of 1.73 × 10-8 mol L-1(S/N = 3). When used for determination of AP in actual samples, the recovery of the sensor to the sample was 95.80-103.76%, and the RSD was 0.78%-3.05%.


Assuntos
Acetaminofen/análise , Analgésicos não Entorpecentes/análise , Técnicas Eletroquímicas/métodos , Imãs/química , Impressão Molecular/métodos , Polímeros/química , Acetaminofen/sangue , Acetaminofen/urina , Analgésicos não Entorpecentes/sangue , Analgésicos não Entorpecentes/urina , Técnicas Biossensoriais/métodos , Humanos , Limite de Detecção , Membranas Artificiais , Comprimidos
17.
Anal Chim Acta ; 1096: 193-202, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31883587

RESUMO

Specific recognition of caffeic acid (CA) from Taraxacum mon-golicum Hand.-Mazz. was successfully performed using a new pH responsive magnetic molecularly imprinted polymers (pH-MMIPs) by simple surface molecular imprinting polymerization. The pH-MMIPs were prepared on the surface of the Fe3O4@SiO2@MPS particles using CA as a template, 2-(dimethylamino) ethyl methacrylate (DMA) as the pH responsive functional monomer, 4-vinylpyridine (4-VP) as an assisting functional monomer, ethylene glycol dimethyl acrylate (EGDMA) as cross-linker, 2,2'-azobisisobutyronitrile (AIBN) as initiator and methanol-H2O (1:1, v/v) as the porogen. The resultant polymers were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), vibrating sample magnetometry (VSM) and x-ray diffraction (XRD). The adsorption experiments revealed that the pH-MMIPs performed high adsorption ability (11.5 mg g-1) by changing solution pH. Successful selective adsorption of CA was achieved with distribution coefficient of 0.12 and 0.21 towards ferulic acid and chlorogenic acid. Furthermore, pH-MMIPs were employed as adsorbents for extraction and enrichment of CA from Taraxacum mon-golicum Hand.-Mazz. extract. The recoveries of CA in the Taraxacum mon-golicum Hand.-Mazz. ranged from 90.47% to 98.97%. The results proved that the polymers have the potential to provide a selective recognition of CA in complex samples by simple pH regulation.


Assuntos
Ácidos Cafeicos/isolamento & purificação , Impressão Molecular/métodos , Polímeros/química , Taraxacum/química , Adsorção , Óxido Ferroso-Férrico/química , Concentração de Íons de Hidrogênio , Imãs/química , Metacrilatos/química , Polimerização , Piridinas/química , Dióxido de Silício/química
18.
Food Chem ; 306: 125455, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31629968

RESUMO

The present research reported a facile strategy for the synthesis of a novel magnetic covalent organic frameworks (Fe3O4@COF(TpDA)) material and applied it as a sorbent for magnetic solid phase extraction of plant growth regulators from fruits and vegetables. The prepared Fe3O4@COF materials showed many attractive features involving large specific surface area (180.2 m2/g) and high saturation magnetization (62.3 emu/g), which enabled it an ideal sorbent for sample pretreatment. The experimental conditions affecting the extraction performance were optimized systematically, including eluent, amount of sorbent, adsorption time and desorption time. The extracted samples were detected by HPLC-DAD. Under the optimized conditions, the proposed method exhibited good linearity (R ≥ 0.9990) and low limits of detection (4.68-7.51 µg/L). Satisfactory recoveries were calculated to be 83.0-105.0%. Finally, the proposed method was successfully applied to determination of plant growth regulators in fruits and vegetables, indicating the potential prospect of the Fe3O4@COF(TpDA) materials in sample pretreatment.


Assuntos
Frutas/química , Estruturas Metalorgânicas/análise , Reguladores de Crescimento de Planta/análise , Verduras/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Magnetismo/métodos , Imãs , Extração em Fase Sólida/métodos
19.
Arch. Soc. Esp. Oftalmol ; 94(12): 605-608, dic. 2019. ilus
Artigo em Espanhol | IBECS | ID: ibc-190013

RESUMO

Los cuerpos extraños intraorbitarios (CEIO) son objetos que se sitúan en la órbita, normalmente metálicos, que pueden llegar a provocar serios daños estructurales y funcionales en el ojo y en el contenido orbitario. Presentamos el caso de un paciente con un CEIO metálico de localización anterior que se extrajo con la ayuda de un electroimán ocular externo tipo Livingston-Mansfield. A pesar de tratarse de un instrumento que podría considerarse «del pasado», sigue teniendo cabida en nuestro medio en determinadas circunstancias


Intraorbital Foreign Bodies (IOFB) are objects, usually of metallic nature, located outside the orbit cavity, and can potentially cause serious damage to ocular and orbital structures. The case is presented of a patient with an anterior metallic IOFB that was extracted with the aid of a Livingston-Mansfield ocular external electromagnet. Despite being an instrument «of the past», we believe that the electromagnet can still be useful in certain circumstances


Assuntos
Adulto , Corpos Estranhos/terapia , Órbita/diagnóstico por imagem , Imãs , Corpos Estranhos/diagnóstico por imagem , Tomografia Computadorizada por Raios X
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