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1.
J Environ Manage ; 270: 110839, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32721303

RESUMO

We aim at fabricating a ternary magnetic recyclable Bi2WO6/BiOI@Fe3O4 composite that could be applied for photodegradation of tetracycline (TC) from synthetic wastewater. To identify any changes with respect to the composite's morphology and crystal structure properties, ΧRD, FTIR, FESEM-EDS, PL and VSM analyses are carried out. The effects of Fe3O4 loading ratio on the Bi2WO6/BiOI for TC photodegradation are evaluated, while operational parameters such as pH, reaction time, TC concentration, and photocatalyst's dose are optimized. Removal mechanisms of the TC by the composite and its photodegradation pathways are elaborated. With respect to its performance, under the same optimized conditions (1 g/L of dose; 5 mg/L of TC; pH 7; 3 h of reaction time), the Bi2WO6/BiOI@5%Fe3O4 composite has the highest TC removal (97%), as compared to the Bi2WO6 (63%). After being saturated, the spent photocatalyst could be magnetically separated from solution for subsequent use. In spite of three consecutive cycles with 71% of efficiency, the spent composite still has reasonable photocatalytic activities for reuse. Overall, this suggests that the composite is a promising photocatalyst for TC removal from aqueous solutions.


Assuntos
Antibacterianos , Tetraciclina , Fenômenos Magnéticos , Magnetismo , Fotólise
2.
Huan Jing Ke Xue ; 41(2): 815-822, 2020 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608742

RESUMO

Antibiotic resistance genes (ARGs) in municipal wastewater pose a potential threat to the environment. In this study, the change in absolute and relative abundance of ARGs, metal resistance genes (MRGs), and mobile genetic elements (MGTs) were investigated during an emergent municipal wastewater treatment by the magnetic separation process. Results indicate that all the concentrations of targeted ARGs, MRGs, and MGTs decreased significantly in the primary and secondary stirring tank. However, the absolute abundance of some ARGs and MRGs increased in the effluent, which is likely caused by the presence of ample MGTs, in the order of int1 (2.00×1010 copies·mL-1) > int2 (1.91×108 copies·mL-1) > Tn 916/1545e(5.38×108 copies·mL-1). The results obtained from network and PCA analysis showed that the removal of ARGs and MRGs were significantly associated with variations in the microbial community and common pollutants in urban wastewater, such as suspended solids, phosphorus, and COD, which are important factors for affecting the removal efficiency of antibiotic resistance genes and metal heavy resistance genes. These results show that magnetic separation can effectively reduce common pollutants in urban wastewater and might further restrict the transmission and transfer of ARGs. Moreover, it is necessary to strengthen the subsequent management of magnetic separation effluent and dehydrated sludge by disinfection technologies to lessen the risk of antimicrobial contamination.


Assuntos
Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Magnetismo , Águas Residuárias , Purificação da Água/métodos , Antibacterianos , Metais Pesados
3.
J Environ Manage ; 270: 110816, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32501235

RESUMO

Disinfection using chlorine has paramount importance in the treatment of either drinking water or sewage since it can kill and inhibit all waterborne pathogens, but it may result in carcinogenic substances when interacting with organic matter. An eco-friendly sol-gel process with citrate was used to prepare the nano-cubic activated nickel-zinc ferrite magnetic nanostructures (Ni0.6Zn0.4Fe2O4 and Ni0.6Zn0.2Ce0.2Fe2O4). The activated nanomagnetic samples were characterized using XRD, HR-TEM, HR-SEM, FTIR, and VSM techniques. The structural and magnetic results showed that the nano-cubes magnetic-structures exhibited higher crystalline degrees and an increase in the total magnetization, enabling spinel nano-ferrite to possess potentials for excellent industry various applications. Likewise, the VSM results reveal that Ce2O3 had a significant influence on the magnetic behavior such as the coercivity (Hc; 69.226-133.15) saturation and magnetization (Ms; 24.562-52.174). The results revealed that all Magnetic nanoparticles (MNPs) had an outstanding inhibitory effect on microbes tested. The manufactured particles showed a remarkable ability to eliminate pathogenic bacteria in real sewage samples. The results obtained endorsed that the manufactured magnetic nanoparticles (MNPs) are powerful nano-weapons with an excellent anticipated output for the deactivation of pathogenic microbes during sewage treatment, with, nickel-zinc-cerium ferrite being more effective in inhibiting microbial growth than nickel-zinc-cerium ferrite.


Assuntos
Nanopartículas , Nanoestruturas , Fenômenos Magnéticos , Magnetismo , Esgotos
5.
Br J Radiol ; 93(1111): 20200113, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32496816

RESUMO

MRI developed during the last half-century from a very basic concept to an indispensable non-ionising medical imaging technique that has found broad application in diagnostics, therapy control and far beyond. Due to its excellent soft-tissue contrast and the huge variety of accessible tissue- and physiological-parameters, MRI is often preferred to other existing modalities. In the course of its development, MRI underwent many substantial transformations. From the beginning, starting as a proof of concept, much effort was expended to develop the appropriate basic scanning technology and methodology, and to establish the many clinical contrasts (e.g., T1, T2, flow, diffusion, water/fat, etc.) that MRI is famous for today. Beyond that, additional prominent innovations to the field have been parallel imaging and compressed sensing, leading to significant scanning time reductions, and the move towards higher static magnetic field strengths, which led to increased sensitivity and improved image quality. Improvements in workflow and the use of artificial intelligence are among many current trends seen in this field, paving the way for a broad use of MRI. The 125th anniversary of the BJR is a good point to reflect on all these changes and developments and to offer some slightly speculative ideas as to what the future may bring.


Assuntos
Invenções/tendências , Imagem por Ressonância Magnética/tendências , Inteligência Artificial/tendências , Meios de Contraste , Aprendizado Profundo/tendências , Humanos , Imagem por Ressonância Magnética/instrumentação , Imagem por Ressonância Magnética/métodos , Magnetismo , Fluxo de Trabalho
6.
Water Sci Technol ; 81(3): 585-595, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32385212

RESUMO

Various magnetic carbon nanotubes (CNTs) Co0.5M0.5Fe2O4-CNTs (M = Cu, Mn, Ni, Zn) were successfully prepared and applied for treatment of pentachlorophenol (PCP) with adsorption and microwave irradiation process. The Co0.5M0.5Fe2O4-CNTs were characterized by transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry, and microwave absorption spectroscopy. The adsorption experiment results showed the adsorption capacity for PCP was in the following order: Co0.5Cu0.5Fe2O4-CNTs > Co0.5Mn0.5Fe2O4-CNTs > Co0.5Ni0.5Fe2O4-CNTs > Co0.5Zn0.5Fe2O4-CNTs. After adsorption, the Co0.5M0.5Fe2O4-CNTs was separated by magnetic field and regenerated by microwave irradiation at 850 W for 180 s. It was confirmed that after six adsorption and microwave regeneration cycles, the regeneration efficiency maintained over 90%. In particular, Co0.5Cu0.5Fe2O4-CNTs exhibited excellent adsorption capacity and reusability. These results can open a new avenue for treatment of chlorinated organic compounds with efficiently and non-secondary pollution.


Assuntos
Nanotubos de Carbono , Pentaclorofenol , Adsorção , Magnetismo , Micro-Ondas
7.
Int J Nanomedicine ; 15: 2583-2603, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368042

RESUMO

Introduction: Over the past several years, nano-based therapeutics were an effective cancer drug candidate in order to overcome the persistence of deadliest diseases and prevalence of multiple drug resistance (MDR). Methods: The main objective of our program was to design organosilane-modified Fe3O4/SiO2/APTS(~NH2) core magnetic nanocomposites with functionalized copper-Schiff base complex through the use of (3-aminopropyl)triethoxysilane linker as chemotherapeutics to cancer cells. The nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), TEM, and vibrating sample magnetometer (VSM) techniques. All analyses corroborated the successful synthesis of the nanoparticles. In the second step, all compounds of magnetic nanoparticles were validated as antitumor drugs through the conventional MTT assay against K562 (myelogenous leukemia cancer) and apoptosis study by Annexin V/PI and AO/EB. The molecular dynamic simulations of nanoparticles were further carried out; afterwards, the optimization was performed using MM+, semi-empirical (AM1) and Ab Initio (STO-3G), ForciteGemo Opt, Forcite Dynamics, Forcite Energy and CASTEP in Materials studio 2017. Results: The results showed that the anti-cancer activity was barely reduced after modifying the surface of the Fe3O4/SiO2/APTS nanoparticles with 2-hydroxy-3-methoxybenzaldehyde as Schiff base and then Cu(II) complex. The apoptosis study by Annexin V/PI and AO/EB stained cell nuclei was performed that apoptosis percentage of the nanoparticles increased upon increasing the thickness of Fe3O4 shell on the magnetite core. The docking studies of the synthesized compounds were conducted towards the DNA and Topoisomerase II via AutoDock 1.5.6 (The Scripps Research Institute, La Jolla, CA, USA). Conclusion: Results of biology activities and computational modeling demonstrate that nanoparticles were targeted drug delivery system in cancer treatment.


Assuntos
Cobre/química , Compostos Férricos/síntese química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Propilaminas/síntese química , Bases de Schiff/síntese química , Silanos/síntese química , Dióxido de Silício/síntese química , Apoptose , Núcleo Celular/metabolismo , DNA/química , DNA Topoisomerases Tipo II/química , Compostos Férricos/química , Humanos , Células K562 , Magnetismo , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/ultraestrutura , Propilaminas/química , Bases de Schiff/química , Silanos/química , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
8.
J Chromatogr A ; 1622: 461137, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32414518

RESUMO

In this study, conventional Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was modified by magnetic solid-phase extraction (MSPE) for purification/pre-concentration of eleven estrogens and estrogen mimics from the extracts of pork and chicken muscles, prior to dansyl chloride (DNS-Cl) derivatization coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay. Dual octadecyl- and 2-aminoethyl-3-aminopropyl- groups functionalized mesoporous silica core-shell magnetic nanoparticles (C18/NH2-Fe3O4@mSiO2 MNPs) were synthesized and employed as MSPE sorbent with remarkable aqueous compatibility in comparison with conventional C18 functionalized sorbent. The proposed MSPE is easier to handle than the traditional SPE purification process in QuEChERS method. The lab-prepared MNPs were characterized by transmission electron microscope (TEM), brunner-emmet-teller (BET), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). Pre-column derivatization was conducted to significantly enhance the sensitivity of the analytes in MS/MS via analyzing their derivatives in positive ion mode instead of analyzing their original forms in negative ion mode. Under the optimal sample pretreatment and instrumental analysis conditions, the approach showed low limits of detection (LODs, 0.02‒3.00 µg kg-1), appropriate recoveries (81.1‒115.4%) and acceptable precisions (0.48‒15.1%, n = 6), with good feasibility and future prospect of trace compounds analysis in complex food samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Estrogênios/análise , Magnetismo , Carne Vermelha/análise , Extração em Fase Sólida/economia , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adsorção , Animais , Galinhas , Concentração de Íons de Hidrogênio , Limite de Detecção , Nanopartículas de Magnetita/ultraestrutura , Concentração Osmolar , Dióxido de Silício/química , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Suínos , Fatores de Tempo
9.
Anticancer Res ; 40(4): 1809-1815, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32234869

RESUMO

BACKGROUND/AIM: Wire-guided localisation (WGL) remains the most widely used technique for the localisation of non-palpable breast lesions; however, recent technological advances have resulted in non-wire, non-radioactive alternatives, such as magnetic seeds (Magseeds). The aim of this pooled analysis was to determine whether Magseeds are an effective tool for localising non-palpable breast lesions. MATERIALS AND METHODS: Various databases were searched for publications which reported data on the localisation and placement rates of Magseed. Data on re-excision rates under use of Magseed and WGL were also collected. RESULTS: Sixteen studies, spanning the insertion of 1,559 Magseeds, were analysed. The pooled analysis showed a successful placement rate of 94.42% and a successful localisation rate of 99.86%. Four studies were analysed in a separate pooled analysis and showed no statistically significant difference between re-excision rates using Magseeds and WGL. CONCLUSION: The use of Magseeds is an effective, non-inferior alternative to WGL that overcomes many of the limitations of the latter.


Assuntos
Neoplasias da Mama/terapia , Mama/efeitos da radiação , Terapia de Campo Magnético , Campos Magnéticos , Mama/patologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Feminino , Humanos , Magnetismo , Mastectomia Segmentar
10.
Food Chem ; 321: 126673, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278983

RESUMO

In this work, a novel method was developed, for isolation of S. aureus from complex (food) samples using molecular imprinting.  Dopamine was used as a functional monomer and fluorescence microscopy was used for detection. Conditions for preparation of molecularly imprinted polymers (MIPs), adsorption performance, adsorption kinetic, and selectivity of the polymeric layers were investigated. The various procedures were combined in a single extraction process, with the imprinted layer on the surface of the magnetic particles (magnetic MIPs). Subsequently, MIPs were used for extraction of S. aureus from milk and rice. Moreover, raw milk from cows with mastitis was tested successfully. Using this novel MIP-based method, it was possible to detect bacteria in milk at 1 × 103CFU·ml-1, which corresponds to the limit set in European Union legislation for microbial control of food.


Assuntos
Leite/microbiologia , Impressão Molecular/métodos , Staphylococcus aureus/isolamento & purificação , Adsorção , Animais , Bovinos , Fenômenos Magnéticos , Magnetismo , Polímeros/química , Extração em Fase Sólida
11.
Nat Commun ; 11(1): 2060, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32345978

RESUMO

Single-molecule methods using recombinant proteins have generated transformative hypotheses on how mechanical forces are generated and sensed in biological tissues. However, testing these mechanical hypotheses on proteins in their natural environment remains inaccesible to conventional tools. To address this limitation, here we demonstrate a mouse model carrying a HaloTag-TEV insertion in the protein titin, the main determinant of myocyte stiffness. Using our system, we specifically sever titin by digestion with TEV protease, and find that the response of muscle fibers to length changes requires mechanical transduction through titin's intact polypeptide chain. In addition, HaloTag-based covalent tethering enables examination of titin dynamics under force using magnetic tweezers. At pulling forces < 10 pN, titin domains are recruited to the unfolded state, and produce 41.5 zJ mechanical work during refolding. Insertion of the HaloTag-TEV cassette in mechanical proteins opens opportunities to explore the molecular basis of cellular force generation, mechanosensing and mechanotransduction.


Assuntos
Conectina/metabolismo , Endopeptidases/genética , Especificidade de Órgãos , Animais , Fenômenos Biomecânicos , Conectina/química , Feminino , Proteínas Imobilizadas/metabolismo , Magnetismo , Camundongos , Músculos/metabolismo , Músculos/ultraestrutura , Pinças Ópticas , Fenótipo , Dobramento de Proteína , Análise Espectral
12.
PLoS One ; 15(4): e0232136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330188

RESUMO

Determining the East-West position was a classical problem in human sea navigation until accurate clocks were manufactured and sailors were able to measure the difference between local time and a fixed reference to determine longitude. Experienced night-migratory songbirds can correct for East-West physical and virtual magnetic displacements to unknown locations. Migratory birds do not appear to possess a time-different clock sense; therefore, they must solve the longitude problem in a different way. We showed earlier that experienced adult (but not juvenile) Eurasian reed warblers (Acrocephalus scirpaceus) can use magnetic declination (the difference in direction between geographic and magnetic North) to solve this problem when they were virtually displaced from Rybachy on the eastern Baltic coast to Scotland. In this study, we aimed to test how general this effect was. Adult and juvenile European robins (Erithacus rubecula) and adult garden warblers (Sylvia borin) under the same experimental conditions did not respond to this virtual magnetic displacement, suggesting significant variation in how navigational maps are organised in different songbird migrants.


Assuntos
Migração Animal/fisiologia , Aves Canoras/fisiologia , Navegação Espacial/fisiologia , Animais , Campos Magnéticos , Magnetismo , Orientação , Passeriformes/fisiologia , Fenômenos Físicos , Escócia
14.
Sci Total Environ ; 720: 137621, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32146403

RESUMO

Innovative iron-based nanoparticles were synthesized, characterized and tested for the first time for harvesting single and mixed algal culture from real wastewater. The tailor-made magnetic nanoparticles (MNPs; Fe-MNP-I and Fe-MNP-II) achieved a percentage algae harvesting efficiency (%AHE) higher than 95% using a concentration of MNPs (CMNP) of 25 ± 0.3 (std. dev = 0.08) mg.L-1, mixing speed (Mspeed) of 120 ± 2 (std. dev = 0.10) rpm, short contact time (Ct) of 7 ± 0.1 (std. dev = 0.05) min and separation time (SPt) of 3 ± 0.1 (std. dev = 0.09) min. The optimum operational conditions for harvesting of Chlorella vulgaris (C.v) were determined at (CMNP = 40 ± 0.4 (std. dev = 0.5) gMNPs.L-1, SPt = 2.5 ± 0.4 (std. dev = 0.1) min, Mspeed = 145 ± 3 (std. dev = 1.50) rpm and Ct = 5 ± 0.3 (std. dev = 0.10) min using surface response methodology. Langmuir model describes better the adsorption behavior of algae-Fe-MNP-I system, while both Langmuir and Freundlich fit well the adsorption behavior of algae-Fe-MNP-II. The maximum adsorption capacity of Spirulina platensis (SP.PL) (18.27 ± 0.07 (std. dev = 0.19) mgDWC.mgparticles-1) was higher than that for Chlorella vulgaris (C.v) (11.52 ± 0.01 (std. dev = 0.34) mgDWC.mgparticles-1) and mixed algal culture (M.X) (17.20 ± 0.07 (std. dev = 0.54) mgDWC.mgparticles-1) over Fe-MNP-I. Zeta potential measurements revealed that the adsorption mechanism between MNPs and algal strains is controlled by electrostatic interaction. The synthesized MNPs were recycled 10 times using alkaline-ultrasonic regeneration procedure.


Assuntos
Chlorella vulgaris , Nanopartículas de Magnetita , Adsorção , Análise Custo-Benefício , Fenômenos Magnéticos , Magnetismo
15.
Chemosphere ; 251: 126384, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32143082

RESUMO

Aminosilane materials, with their low cost and ease of modification, have exhibited great potential for the adsorption of perfluorinated compounds (PFCs) from water. However, this kind of material may be facing two drawbacks during its application: low resistance to hydrolysis and difficulties in separation from the water matrix. This work proposed a strategy of grafting N-(2-aminoethyl) aminopropyltrimethoxysilane (AE-APTMS) on the surface of magnetic γ-Fe2O3 nanoparticles by full utilization of the sorption sites provided by the aminosilane and the magnetism by γ-Fe2O3. The FTIR and XRD results verified the formation of the magnetic AE-APTMS nanocomposite. The core-shell nanocomposite showed a superparamagnetic property and an isoelectric point at pH = 8.2. Particularly, compared to the aminopropyltriethoxysilane (APTES) nanocomposite, the AE-APTMS nanocomposite exhibited improved hydrolytic stability with 60% less loss of the amine groups during the 48 h adsorption process, as the longer alkyl chain hindered the aminosilane detachment. The AE-APTMS nanocomposite exhibited a rapid adsorption with the removal efficiency of 78% for perfluorooctane sulfonate (PFOS) and 65% for perfluorooctanoate (PFOA) due to the electrostatic interaction and hydrophobic interaction. The regeneration and reuse of the magnetic AE-APTMS nanocomposite were conveniently realized with the removal efficiency higher than 70% for both PFOS and PFOA even after 15 adsorption-desorption cycles. The stable magnetic aminosilane nanocomposite with the ease of separation may provide a new strategy to achieve the economical and effective removal of typical PFCs from water.


Assuntos
Ácidos Alcanossulfônicos/química , Caprilatos/química , Fluorcarbonetos/química , Nanocompostos/química , Poluentes Químicos da Água/química , Adsorção , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Magnetismo , Propilaminas , Silanos , Água , Poluentes Químicos da Água/análise , Purificação da Água/métodos
16.
Mol Biol (Mosk) ; 54(1): 114-127, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32163395

RESUMO

The factors that affect the labeling of NIH 3T3 murine fibroblasts with Fe3O4-based magnetic nanoparticles (MNPs) were studied using MNPs produced by the gas condensation and solution precipitation methods and MNPs surface-modified with 3-aminopropylsilane or L-lysine. The production method, surface modifications, the particle concentration and size, the state of the cell population, and the method of MNP introduction were found to substantially affect the efficiency of MNP binding by cells. In particular, large MNP clusters may occur in MNP suspensions in DMSO, and their disruption by sonication increased the percent yield of magnetically labeled cells. Static incubation of a cell suspension led to a more efficient labeling as compared with continuous agitation. Cells attached to a plastic support could be labeled to a higher degree than cells in suspension, but required substantially longer incubations with MNPs. MNP centrifugation on cell layers (magnetic spinoculation) significantly increased the rate and efficiency of labeling. The stability of magnetic labeling was shown to depend on the MNP dose during labeling. Electron microscopy studies demonstrated that MNPs were associated with the cell surface after 20-min incubation with cells and were mostly in the cell interior after 4-h incubation. The results of the study may be useful for preparation and application of magnetized cell samples.


Assuntos
Separação Celular/métodos , Nanopartículas de Magnetita/análise , Nanopartículas de Magnetita/química , Coloração e Rotulagem/métodos , Animais , Magnetismo , Camundongos , Células NIH 3T3
17.
PLoS One ; 15(3): e0229142, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32134934

RESUMO

Migratory birds can detect the direction of the Earth's magnetic field using the magnetic compass sense. However, the sensory basis of the magnetic compass still remains a puzzle. A large body of indirect evidence suggests that magnetic compass in birds is localized in the retina. To confirm this point, an evidence of visual signals modulation by magnetic field (MF) should be obtained. In a previous study we showed that MF inclination impacts the amplitude of ex vivo electroretinogram (ERG) recorded from isolated pigeon retina. Here we present the results of an analysis of putative MF effect on one component of ERG, the photoreceptor's response, isolated from the total ERG by adding sodium aspartate and barium chloride to the perfusion solution. Photoresponses were recorded from isolated retinae of domestic pigeons Columba livia. The retinal samples were placed in MF that was modulated by three pairs of orthogonal Helmholtz coils. Light stimuli (blue and red) were applied under two inclinations of MF, 0° and 90°. In all the experiments, preparations from two parts of retina were used, red field (with dominant red-sensitive cones) and yellow field (with relatively uniform distribution of cone color types). In contrast to the whole retinal ERG, we did not observe any effect of MF inclination on either amplitude or kinetics of pharmacologically isolated photoreceptor responses to blue or red half-saturating flashes. A possible explanations of these results could be that magnetic compass sense is localized in retinal cells other than photoreceptors, or that photoreceptors do participate in magnetoreception, but require some processing of compass information in other retinal layers, so that only whole retina signal can reflect the response to changing MF.


Assuntos
Migração Animal/fisiologia , Columbidae/anatomia & histologia , Campos Magnéticos , Orientação Espacial/fisiologia , Células Fotorreceptoras de Vertebrados/fisiologia , Retina/anatomia & histologia , Resposta Táctica/fisiologia , Animais , Cor , Eletrorretinografia/veterinária , Fundo de Olho , Luz , Magnetismo , Estimulação Luminosa , Células Fotorreceptoras de Vertebrados/citologia , Retina/citologia , Retina/diagnóstico por imagem , Células Fotorreceptoras Retinianas Cones/citologia , Células Fotorreceptoras Retinianas Cones/fisiologia
18.
Chemosphere ; 252: 126529, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32220718

RESUMO

Magnetic ferrite/biochar composites are a kind of promising adsorbents due to their high adsorption efficiency and facile magnetic separation; however, their synthesis is associated with high cost and secondary environmental impacts. In this study, a novel Mn-Zn ferrite/biochar composite (MZF-BC) is synthesized via a green two-step biocheaching and hydrothermal method using waste batteries and pine sawdust. Characterization results indicate that the introduced Mn-Zn ferrite particles are successfully embedded and coated on biochar (BC), and synthesized MZF-BC50 with 50% BC content exhibits best performance with a specific surface area of 138.5 m2 g-1, the saturation magnetization of 27.5 emu g-1 and CEC value of 53.2 mmol 100 g-1. The maximum adsorption capacity of Pb2+ is 99.5 mg g-1 based on the Langmuir sorption isotherm study at 298 K, and pseudo-second-order model accurately describes the adsorption process. Regeneration test suggests that MZF-BC50 can be efficiently reused for 6 cycles. In addition, it exhibits a good selective Pb2+ and Cd2+ removal performance in lead-acid battery wastewater. The results illustrate that this newly developed material has low cost and rapid remediation of Pb2+ as good application potential.


Assuntos
Fontes de Energia Elétrica , Chumbo/química , Eliminação de Resíduos/métodos , Adsorção , Carvão Vegetal/química , Compostos Férricos/química , Química Verde , Cinética , Magnetismo , Águas Residuárias , Poluentes Químicos da Água/análise , Madeira/química , Zinco
20.
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
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