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1.
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
2.
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
3.
J Chromatogr A ; 1625: 461343, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709308

RESUMO

A simple magnetic dispersive solid-phase extraction (MDSPE) methodology based on mesoporous Fe3O4@ succinic acid nanospheres and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has been developed to determine kanamycin (KNM) and neomycin (NEO) contents in Measles, Mumps, and Rubella (MMR) vaccine products. The monodispersed mesoporous Fe3O4 nanospheres with self-assembled carboxyl terminated shell have been prepared via a simple solvothermal method. These as-synthesized mesoporous Fe3O4 nanospheres showed a high magnetic saturation value (Ms = 46 emu g-1) and large specific surface area (111.12 m2 g-1) which made them potential candidates as sorbents in magnetic solid-phase extraction. The adsorption experimental data fitted well with the Freundlich-Langmuir isotherm and followed a pseudo-second-order kinetic model. Moreover influential parameters on extraction efficiency were investigated and optimized. Under optimal conditions, the limits of detection for KNM and NEO were 1.0 and 0.1 ng mL-1, respectively. Recovery assessments using real samples exhibited recoveries in the range of 96.0 ± 4.3 to 101.5 ± 7.1 %, with relative standard deviations of <10.7% (for intra- day) and <14.6% (for inter- day). The proposed method was successfully applied for different spiked and un-spiked MMR vaccine samples. The presented extraction method provides a fast, selective, robust and practical platform for the detection of KNM and NEO in MMR vaccine samples.


Assuntos
Dextranos/química , Canamicina/análise , Nanopartículas de Magnetita/química , Vacina contra Sarampo/análise , Caxumba/imunologia , Nanosferas/química , Neomicina/análise , Vacina contra Rubéola/análise , Espectrometria de Massas em Tandem/métodos , Adsorção , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Cinética , Limite de Detecção , Magnetismo , Nanosferas/ultraestrutura , Reprodutibilidade dos Testes , Extração em Fase Sólida , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Ácido Succínico/química , Fatores de Tempo , Água/química
5.
J Chromatogr A ; 1624: 461229, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540071

RESUMO

This work describes a sensitive and rapid analytical method for trace determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic samples. The proposed method is based on stir bar sorptive-dispersive microextraction (SBSDME). A magnetic composite made of CoFe2O4 magnetic nanoparticles embedded into reduced graphene oxide sheets is used as sorbent phase. After the extraction, the target analytes are desorbed in toluene and then analyzed by gas chromatography-mass spectrometry (GC-MS). The main parameters involved in the extraction procedure (i.e., composite amount, extraction time and desorption time) were evaluated and optimized to provide the best extraction efficiency. The method was successfully validated under the selected conditions, showing a linear range of at least up to 125 ng mL-1, instrumental and method limits of detection from 0.02 to 2.50 ng mL-1 and from 0.15 to 24.22 ng g-1, respectively, and relative standard deviations (RSD) below 10 % for all the target analytes. Standard addition combined with internal standard calibration was employed for quantification. The proposed method was successfully applied to the analysis of ten PAHs in four cosmetic products of different matrix. Several analytes between 14 and 464 ng g-1 were found, some of them prohibited in cosmetic products. This work expands the analytical potential of SBSDME technique to other analytes and to the use of new sorbent phases, showing the great versatility of this approach depending on the characteristics of the analytes.


Assuntos
Cosméticos/análise , Cromatografia Gasosa-Espectrometria de Massas , Grafite/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Microextração em Fase Sólida/métodos , Cobalto/química , Compostos Férricos/química , Limite de Detecção , Magnetismo , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação
7.
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
8.
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
9.
Biosens Bioelectron ; 165: 112356, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32510339

RESUMO

Circle-to-circle amplification (C2CA) is a specific and precise cascade nucleic acid amplification method consisting of more than one round of padlock probe ligation and rolling circle amplification (RCA). Although C2CA provides a high amplification efficiency with a negligible increase of false-positive risk, it contains several step-by-step operation processes. We herein demonstrate a homogeneous and isothermal nucleic acid quantification strategy based on C2CA and optomagnetic analysis of magnetic nanoparticle (MNP) assembly. The proposed homogeneous circle-to-circle amplification eliminates the need for additional monomerization and ligation steps after the first round of RCA, and combines two amplification rounds in a one-pot reaction. The second round of RCA produces amplicon coils that anneal to detection probes grafted onto MNPs, resulting in MNP assembly that can be detected in real-time using an optomagnetic sensor. The proposed methodology was applied for the detection of a synthetic complementary DNA of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2, also known as 2019-nCoV) RdRp (RNA-dependent RNA polymerase) coding sequence, achieving a detection limit of 0.4 fM with a dynamic detection range of 3 orders of magnitude and a total assay time of ca. 100 min. A mathematical model was set up and validated to predict the assay performance. Moreover, the proposed method was specific to distinguish SARS-CoV and SARS-CoV-2 sequences with high similarity.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Infecções por Coronavirus/diagnóstico , DNA Complementar/análise , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Pneumonia Viral/diagnóstico , Técnicas Biossensoriais/métodos , Desenho de Equipamento , Estudos de Viabilidade , Humanos , Limite de Detecção , Magnetismo/instrumentação , Magnetismo/métodos , Nanopartículas de Magnetita/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Pandemias
10.
Environ Sci Pollut Res Int ; 27(27): 34311-34321, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32542569

RESUMO

This study investigates the impact of an engineered magnetic nanoparticle (MNP) on a crop plant. For this purpose, a sonochemical synthetic approach was utilized in order to dope magnetic elements (Co and Nd) into technologically important iron oxide NPs. After being characterized by using TEM, SEM, and XRD instruments, the MNPs were hydroponically applied to barley plants with varying doses (from 125 to 1000 mg/L) both in germination (4 days) and early growing stages (3 weeks). Physiological responses, as well as expression of photosystem marker genes, were assessed. Compared to the untreated control, MNP treatment enhanced germination rate (~ 31%), tissue growth (8% in roots, 16% in shoots), biomass (~ 21%), and chlorophyll (a, b) (~ 20%), and carotenoids (~ 22%) pigments. In general, plants showed the highest growth enhancement at 125 or 250 mg/L treatment. However, higher doses diminished the growth indices. Compared to the control, the catalase activity was significantly reduced in the leaves (~ 33%, p < 0.005) but stimulated in the roots (~ 46%, p < 0.005). All tested photosystem marker genes (BCA, psbA, and psaA) were overexpressed in MNP-treated leaves than non-treated control. Moreover, the gene expressions were found to be proportionally increased with increasing MNP doses, indicating a positive correlation between MNPs and the photosynthetic machinery, which could contribute to the enhancement of plant growth.


Assuntos
Nanopartículas de Magnetita , Nanopartículas , Clorofila , Hordeum , Magnetismo , Folhas de Planta , Raízes de Plantas
11.
Environ Sci Pollut Res Int ; 27(29): 37011-37021, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32577974

RESUMO

A large number of iron ore tailings (IOTs) are produced in steel industry, posing threat to the environment during its storage and disposal. To effectively reutilize Fe in IOTs, we propose a comprehensive utilization scheme: (1) most Fe in IOTs is extracted by concentrated hydrochloric acid to form FeCl3 flocculants; (2) after separation from the FeCl3 flocculants, a small amount of Fe is absorbed on the residue solids, which is further washed out to synthesize micron Fe3O4 as magnetic seeds. Results show that the as-synthetic FeCl3 flocculants meet the product standard for FeCl3 flocculants in China (GB/T 4482-2018) after a series of treatments including rotary evaporation, neutralization, and dilution and have comparable performance with commercial polyaluminum chloride (PAC) and polyaluminum ferric chloride (PAFC). Moreover, the addition of synthetic superparamagnetic Fe3O4 (as magnetic seeds) doubled the flocculation rate compared with as-synthetic FeCl3 flocculants alone. Finally, the reutilization of Fe in IOTs can create a direct economic value of ¥ 1.27/kg IOTs, and produce 745 g high-silicon residues for further reutilization, which indicates that our comprehensive utilization scheme is of great application potential.


Assuntos
Ferro , Magnetismo , China , Floculação , Fenômenos Magnéticos
12.
PLoS One ; 15(6): e0234136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520947

RESUMO

Groundwater treatment sludge is a Fe/Mn-bearing waste that is mass produced in groundwater treatment plant. In this study, sludge was converted to a magnetic adsorbent (MA) by adding ascorbate. The sludge was weakly magnetised in the amorphous form with Fe and Mn contents of 28.8% and 8.1%, respectively. After hydrothermal treatment, Fe/Mn oxides in the sludge was recrystallised to siderite and rhodochrosite, with jacobsite as the intermediate in the presence of ascorbate. With an increment in ascorbate dosage, the obtained magnetic adsorbent had a significant increase in chromate adsorption but a decrease in magnetisation. When the Mascorbate/MFe molar ratio was 10, the produced MA-10 was a dumbbell-shaped nanorod with a length of 2-5 µm and a diameter of 0.5-1 µm. This MA-10 showed 183.2 mg/g of chromate adsorption capacity and 2.81 emu/g of magnetisation. The mechanism of chromate adsorption was surface coprecipitation of the generated Cr3+ and Fe3+/Mn4+ from redox reaction between chromate and siderite/rhodochrosite on MA-10, separately. This study demonstrated an efficient recycling route of waste sludge from groundwater treatment to produce MA for treating chromate-bearing wastewater.


Assuntos
Cromatos/química , Magnetismo , Nanotubos/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Carbonatos/química , Compostos Férricos/química , Ferro/química , Cinética , Manganês/química , Oxirredução , Óxidos/química
13.
PLoS One ; 15(6): e0231854, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32479545

RESUMO

UltraPrep is an open-source, two-step method for purification of cell-free DNA that entails extraction of total DNA followed by size-selective enrichment of the smaller fragments that are characteristic of DNA originating from fragmentation between nucleosome. The advantages of the two related protocols that are described are that they can easily accommodate a wide range of sample input volumes, they rely on simple, magnetic bead-based technology, the yields of cfDNA are directly comparable to the most popular methods for cfDNA purification, and they dramatically reduce the cost of cfDNA isolation relative to currently available commercial methods. We provide a framework for physical and molecular quality analysis of purified cfDNA and demonstrate that the cfDNA generated by UltraPrep meets or exceeds the quality metrics of the most commonly used procedure. In addition, our method removes high molecular weight genomic DNA (hmwgDNA) that can interfere with downstream assay results, thereby addressing one of the primary concerns for preanalytical collection of blood samples.


Assuntos
Ácidos Nucleicos Livres/isolamento & purificação , Extração em Fase Sólida/métodos , Ácidos Nucleicos Livres/sangue , Humanos , Biópsia Líquida , Magnetismo , Nucleossomos/genética , Dióxido de Silício/química , Extração em Fase Sólida/economia
14.
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
15.
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
16.
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
17.
Nat Commun ; 11(1): 2637, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32457457

RESUMO

Metachronal waves commonly exist in natural cilia carpets. These emergent phenomena, which originate from phase differences between neighbouring self-beating cilia, are essential for biological transport processes including locomotion, liquid pumping, feeding, and cell delivery. However, studies of such complex active systems are limited, particularly from the experimental side. Here we report magnetically actuated, soft, artificial cilia carpets. By stretching and folding onto curved templates, programmable magnetization patterns can be encoded into artificial cilia carpets, which exhibit metachronal waves in dynamic magnetic fields. We have tested both the transport capabilities in a fluid environment and the locomotion capabilities on a solid surface. This robotic system provides a highly customizable experimental platform that not only assists in understanding fundamental rules of natural cilia carpets, but also paves a path to cilia-inspired soft robots for future biomedical applications.


Assuntos
Células Artificiais , Cílios/fisiologia , Células Artificiais/ultraestrutura , Cílios/ultraestrutura , Simulação por Computador , Hidrodinâmica , Magnetismo , Modelos Biológicos , Movimento (Física) , Impressão Tridimensional/instrumentação , Robótica/instrumentação
18.
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
19.
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
20.
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
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