Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
1.
Anal Chem ; 96(21): 8484-8491, 2024 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-38753368

RESUMO

It is challenging to prepare a highly selective mass spectrometry (MS) ion source for the rapid and highly sensitive detection of analytes, especially mycotoxins. In this study, an amino and tetrazine bifunctionalized multiarm PEG derivative (NH2HCl-4armPEG10K-(MTz)3), which can be easily immobilized on the substrate by the addition reaction between amino and polydopamine, was used for the preparation of MS ionization substrate. NH2HCl-4armPEG10K-(MTz)3 can also be used as a linker to immobilize sufficient streptavidin (SA) on the surface of the substrate by a click reaction. The process further promotes the immobilization of broad-spectrum antibodies (3D4), which were used as the recognition element for ZEN and its metabolites. The prepared SSS-Au-PDA-4armPEG10K-SA-3D4 not only can rapidly enrich ZEN and its metabolites with high selectivity but also shows good antifouling properties in the matrix. After simple sample preparation, the prepared SSS-Au-PDA-4armPEG10K-SA-3D4 can be directly coupled with MS to achieve high sensitivity (LODs: 0.18-0.66 ng/mL, LOQs: 0.5-1.0 ng/mL) and selective detection of ZEN and its metabolites in the matrix. At the same time, satisfactory recoveries (83.60-97.80%) and precision (RSD: 2.80-9.10%) can also be obtained. The prepared SSS-Au-PDA-4armPEG10K-SA-3D4 is expected to provide a powerful tool for the rapid and highly sensitive determination of multiple targets by MS.


Assuntos
Polietilenoglicóis , Polietilenoglicóis/química , Espectrometria de Massas , Animais , Incrustação Biológica/prevenção & controle , Limite de Detecção
2.
Anal Chem ; 96(31): 12817-12826, 2024 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-39052489

RESUMO

Single-cell analysis by mass spectrometry (MS) is emerging as a powerful tool that not only contributes to cellular heterogeneity but also offers an unprecedented opportunity to predict pathology onset and facilitates novel biomarker discovery. However, the development of single-cell MS analysis techniques with a focus on sample extraction, separation, and ionization methods for volume-limited samples and complexity of cellular samples are still a big challenge. In this study, we present a high-throughput approach to inkjet drop on demand printing single-cell MS for rapid screening of biomarkers of polycyclic aromatic hydrocarbon (PAH) exposure at the KYSE-150 cell, aiming to elucidate the pathogenesis of PAH-induced esophageal cancer. With an analytical bulk KYSE-150 cell throughput of up to 51 cells per minute, the method provides a new opportunity for simultaneous single-cell analysis of multiple biomarkers. We screened 930 characteristic ions from 3,683 detected peak signals and identified 91 distinctive molecules that exhibited significant differences under various concentrations of PAH exposure. These molecules have potential as clinical diagnostic biomarkers. Additionally, the current study identifies specific biomarkers that behave completely opposite in single-cell and multicell lipidomics as the concentration of PAH changes. These biomarkers potentially subdivide KYSE-150 cells into PAH-sensitive and PAH-insensitive types, providing a basis for revealing PAH toxicity and disease pathogenesis from the heterogeneity of cellular metabolism.


Assuntos
Espectrometria de Massas , Hidrocarbonetos Policíclicos Aromáticos , Análise de Célula Única , Hidrocarbonetos Policíclicos Aromáticos/análise , Humanos , Biomarcadores/metabolismo , Biomarcadores/análise , Linhagem Celular Tumoral , Impressão , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/análise
3.
Virol J ; 21(1): 35, 2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38297280

RESUMO

BACKGROUND: Progressive hepatitis B virus (HBV) infection can result in cirrhosis, hepatocellular cancer, and chronic hepatitis. While antiviral drugs that are now on the market are efficient in controlling HBV infection, finding a functional cure is still quite difficult. Identifying host factors involved in regulating the HBV life cycle will contribute to the development of new antiviral strategies. Zinc finger proteins have a significant function in HBV replication, according to earlier studies. Zinc finger protein 148 (ZNF148), a zinc finger transcription factor, regulates the expression of various genes by specifically binding to GC-rich sequences within promoter regions. The function of ZNF148 in HBV replication was investigated in this study. METHODS: HepG2-Na+/taurocholate cotransporting polypeptide (HepG2-NTCP) cells and Huh7 cells were used to evaluate the function of ZNF148 in vitro. Northern blotting and real-time PCR were used to quantify the amount of viral RNA. Southern blotting and real-time PCR were used to quantify the amount of viral DNA. Viral protein levels were elevated, according to the Western blot results. Dual-luciferase reporter assays were used to examine the transcriptional activity of viral promoters. ZNF148's impact on HBV in vivo was investigated using an established rcccDNA mouse model. RESULTS: ZNF148 overexpression significantly decreased the levels of HBV RNAs and HBV core DNA in HBV-infected HepG2-NTCP cells and Huh7 cells expressing prcccDNA. Silencing ZNF148 exhibited the opposite effects in both cell lines. Furthermore, ZNF148 inhibited the activity of HBV ENII/Cp and the transcriptional activity of cccDNA. Mechanistic studies revealed that ZNF148 attenuated retinoid X receptor alpha (RXRα) expression by binding to the RXRα promoter sequence. RXRα binding site mutation or RXRα overexpression abolished the suppressive effect of ZNF148 on HBV replication. The inhibitory effect of ZNF148 was also observed in the rcccDNA mouse model. CONCLUSIONS: ZNF148 inhibited HBV replication by downregulating RXRα transcription. Our findings reveal that ZNF148 may be a new target for anti-HBV strategies.


Assuntos
Vírus da Hepatite B , Hepatite B , Animais , Humanos , Camundongos , DNA Viral/genética , Células Hep G2 , Vírus da Hepatite B/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Replicação Viral
4.
Dig Dis Sci ; 69(4): 1274-1286, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38446308

RESUMO

BACKGROUND & AIMS: Kinesin family member 18A (KIF18A) is notable for its aberrant expression across various cancer types and its pivotal role is driving cancer progression. In this study, we aim to investigate the intricate molecular mechanisms underlying the impact of KIF18A on the progression of HCC. METHODS: Western blotting assays, a quantitative real-time PCR and immunohistochemical analyses were performed to quantitatively assess KIF18A expression in HCC tissues. We then performed genetic manipulations within HCC cells by silencing endogenous KIF18A using short hairpin RNA (shRNA) and introducing exogenous plasmids to overexpress KIF18A. We monitored cell progression, analyzed cell cycle and cell apoptosis and assessed cell migration and invasion both in vitro and in vivo. Moreover, we conducted RNA-sequencing to explore KIF18A-related signaling pathways utilizing Reactome and KEGG enrichment methods and validated these critical mediators in these pathways. RESULTS: Analysis of the TCGA-LIHC database revealed pronounced overexpression of KIF18A in HCC tissues, the finding was subsequently confirmed through the analysis of clinical samples obtained from HCC patients. Notably, silencing KIF18A in cells led to an obvious inhibition of cell proliferation, migration and invasion in vitro. Furthermore, in subcutaneous and orthotopic xenograft models, suppression of KIF18A sgnificantly redudce tumor weight and the number of lung metastatic nodules. Mechanistically, KIF18A appears to facilitate cell proliferation by upregulating MAD2 and CDK1/CyclinB1 expression levels, with the activation of SMAD2/3 signaling contributing to KIF18A-driven metastasis. CONCLUSION: Our study elucidates the molecular mechanism by which KIF18A mediates proliferation and metastasis in HCC cells, offering new insights into potential therapeutic targets.


Assuntos
Carcinoma Hepatocelular , Cinesinas , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Cinesinas/genética , Cinesinas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , RNA Interferente Pequeno
5.
Mikrochim Acta ; 191(4): 220, 2024 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-38532188

RESUMO

Recently, covalent organic frameworks have gained popularity in sample pretreatment. However, the application of covalent organic frameworks in the enrichment of hydrophilic compounds remains a challenge. Thus, a functionalized magnetic covalent organic framework equipped with amino groups was constructed using a bottom-up functionalization strategy. Considering the advantages of this novel adsorbent such as high porosity, large adsorption capacity, and hydrophilic surface, a sensitive magnetic solid-phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry method was established for the effective determination of neonicotinoids. This method exhibited good linearities with correlation coefficients ranging from 0.9983 to 0.9995, low detection limits in the range 0.003-0.009 ng g-1 and 0.001-0.013 ng mL-1, and limits of quantification in the range 0.010-0.031 ng g-1 and 0.004-0.044 ng mL-1. Furthermore, satisfactory repeatability with relative standard deviations ≤ 6.7% and spiked recoveries between 82.3 and 99.8% were obtained. This work not only provided a promising adsorbent for the sensitive determination of trace-level neonicotinoids but also represented a unique insight for effective enrichment of super hydrophilic hazards.


Assuntos
Estruturas Metalorgânicas , Estruturas Metalorgânicas/química , Neonicotinoides , Magnetismo , Cromatografia Líquida de Alta Pressão , Fenômenos Magnéticos
6.
Hepatology ; 75(4): 847-865, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34626132

RESUMO

BACKGROUND AND AIMS: The mechanism underlying HCC metastasis remains unclear, many oncogenes are known to regulate this process. However, the role of alternative splicing (AS) in pro-metastatic HCC is poorly understood. APPROACH AND RESULTS: By performing RNA sequencing on nine pairs of primary HCC tissues with extrahepatic metastasis (EHMH) and nine pairs of metastasis-free HCC (MFH) tissues, we depicted the AS landscape in HCC and found a higher frequency of AS events in EHMH compared with MFH. Moreover, 28 differentially expressed splicing regulators were identified in EHMH compared with MFH. Among these, DEAD-box RNA helicase 17 (DDX17) was significantly up-regulated in EHMH and was strongly associated with patient outcome. Functional studies indicated that DDX17 knockout inhibited the degradation of the extracellular matrix, and diminished the invasive ability of HCC cells. A significant reduction in lung metastasis induced by DDX17 deficiency was also demonstrated in a diethylnitrosamine-induced DDX17HKO mouse model. Mechanistically, high DDX17 induced intron 3 retention of PXN-AS1 and produced a transcript (termed PXN-AS1-IR3). The transcript PXN-AS1-IR3 acted as an important promoter of HCC metastasis by inducing MYC transcription activation via recruiting the complex of testis expressed 10 and p300 to the MYC enhancer region, which led to transcriptional activation of several metastasis-associated downstream genes. Finally, the PXN-AS1-IR3 level was significantly higher in serum and HCC tissues with extrahepatic metastasis. CONCLUSIONS: DDX17 and PXN-AS1-IR3 act as important metastatic promoters by modulating MYC signaling, suggesting that DDX17 and PXN-AS1-IR3 may be potential prognostic markers for metastatic HCC.


Assuntos
Carcinoma Hepatocelular , RNA Helicases DEAD-box , Neoplasias Hepáticas , MicroRNAs , RNA Longo não Codificante , Processamento Alternativo , Animais , Carcinogênese/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , RNA Helicases DEAD-box/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/patologia , Masculino , Camundongos , MicroRNAs/genética , Metástase Neoplásica , Oncogenes , Isoformas de Proteínas/genética , Proteínas Proto-Oncogênicas c-myc/genética , RNA Longo não Codificante/genética , Transdução de Sinais
7.
Electrophoresis ; 43(18-19): 1841-1849, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35562841

RESUMO

Sorghum is an important grain with a high economic value for liquor production. Tracing the geographical origin of sorghum is vital to guarantee the liquor flavor. Soldering iron-based rapid evaporative ionization mass spectrometry (REIMS) combined with chemometrics was developed for the real-time discrimination of the sorghum's geographical origin. The working conditions of soldering iron-based ionization were optimized, and then the obtained MS profiling data were processed using chemometrics analysis methods, including principal component analysis-linear discriminant analysis and orthogonal projection to latent structures discriminant analysis (OPLS-DA). A recognition model was established, and discriminations of sorghum samples from 10 provinces in China were achieved with a correct rate higher than 90%. On the basis of OPLS-DA, the specific ions of m/z 279.2327, 281.2479, and 283.2639 had relatively strong discrimination power for the geographical origins of sorghum. The developed method was successfully applied in the discrimination of sorghum origins. The results indicated that the soldering iron-based REIMS technique combined with chemometrics is a useful tool for direct, fast, and real-time ionization of poor conductivity samples and acquisition of metabolic profiling data.


Assuntos
Sorghum , Quimiometria , Análise Discriminante , Grão Comestível , Ferro , Espectrometria de Massas/métodos
8.
Mikrochim Acta ; 189(10): 389, 2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-36136158

RESUMO

We report a molecularly imprinted polymer electrochemiluminescence (MIP-ECL) sensor with dual recognition effects on dopamine (DA). Boric-acid-functionalized carbon dots (B-CDs) with good ECL performance at - 2.0 V (vs. Ag/AgCl) were prepared and immobilized on a glassy carbon electrode (GCE). The MIP was then introduced via electropolymerization using o-phenylenediamine (OPD) as a functional monomer and DA as a template molecule to fabricate the MIP-ECL sensor. The cavities in the MIP after elution were used to capture the target molecular DA. The affinity of boric acid of B-CDs to the cis-diol of DA, as well as the special recognition of MIP, provides dual recognition effects on DA. The selective readsorption of DA onto the sensor leads to the ECL quenching of B-CDs. The quenching effect was used to detect DA from 1.0 × 10-9 to 1.0 × 10-5 mol·L-1 with a detection limit of 2.1 × 10-10 mol·L-1. The dual recognition caused the MIP-ECL sensor exhibiting excellent selectivity and sensitivity toward  DA. The sensor was successfully used to determine DA in real samples.


Assuntos
Impressão Molecular , Ácidos Bóricos , Carbono , Dopamina , Técnicas Eletroquímicas , Polímeros Molecularmente Impressos
9.
Anal Bioanal Chem ; 413(28): 7021-7030, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34642779

RESUMO

Understanding the spatial distribution of bioactive small molecules is indispensable for elucidating their biological or pharmaceutical roles. Here, a rapid and effective analysis strategy was introduced to study the distribution of veterinary drugs in aquatic products. Malachite green (MG), one of the most widely used veterinary drugs in aquaculture, was selected as the targeted compound. Zebrafish (Danio rerio) was used as a model organism. After an exposure test, the matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technique was applied to directly analyze the content changes of malachite green in zebrafish tissues. The reliable relationship of exposure time and content change of MG was described precisely by the extended Freundlich equation. The process of modeling was discussed in detail, and some important parameters or trend information was obtained, including the maximum content of MG in different fish tissues, time to maximum content, elimination time, equilibrium content, and so on. With a simplification of sample pretreatment, this research strategy can be used for monitoring the spatial distribution of veterinary drugs and related metabolites of laboratory-exposed fish. The obtained model can provide a perspective for rational drug use in aquaculture and precise drug residue detection in production activities.


Assuntos
Corantes de Rosanilina/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Modelos Químicos , Padrões de Referência , Corantes de Rosanilina/normas , Peixe-Zebra
10.
J Sep Sci ; 44(9): 1833-1842, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33586849

RESUMO

Heterocyclic aromatic amines, as a group of mutagenic and carcinogenic compounds, have gained worldwide concern. In this study, an accurate, rapid, and sensitive confirmation and quantification method of four major heterocyclic aromatic amines in roasted pork was developed based on Q-Orbitrap along with Quick, Easy, Cheap, Effective, Rugged, and Safe extraction. The limit of detections and limit of quantitations were found to be 0.2-1.2 µg/kg and 0.6-3.5 µg/kg, respectively, revealing the high sensitivity of this method. Obtained results showed recoveries ranging from 78.1 to 97.4%, depending on the different heterocyclic aromatic amines and spiked levels. Precision was in the range of 2.6-4.5% for four heterocyclic aromatic amines at different levels. In addition, the developed method had been applied to investigate the inhibitory effects of astaxanthin on the above-mentioned heterocyclic aromatic amines in roasted pork. The amount of astaxanthin with the best inhibitory effects was 7.5 mg (0.0375%), which led to significant reduction in heterocyclic aromatic amines levels over 50%.


Assuntos
Aminas/análise , Análise de Alimentos , Compostos Heterocíclicos/análise , Carne de Porco/análise , Aminas/antagonistas & inibidores , Animais , Compostos Heterocíclicos/antagonistas & inibidores , Suínos , Xantofilas/química , Xantofilas/farmacologia
11.
Mikrochim Acta ; 188(8): 246, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34235593

RESUMO

Magnetic covalent organic framework nanocomposite denoted as Fe3O4@TAPB-Tp with core-shell structure was fabricated via a simple template-mediated precipitation polymerization method at mild conditions. The polyimine network shell was created through the polymerization of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformyl-phloroglucinol (Tp) in tetrahydrofuran (THF) by the Schiff-base reaction. Featuring with large specific surface area (163.19 m2 g-1), good solution dispersibility, and high stability, the obtained Fe3O4@TAPB-Tp exhibited high adsorption capacities and fast adsorption for zearalenone and its derivatives (ZEAs). The adsorption isotherms showed multilayer adsorption dominated at low concentration and monolayer adsorption at high concentration between the interface of ZEAs and Fe3O4@TAPB-Tp. With the Fe3O4@TAPB-Tp as sorbent, a magnetic solid-phase extraction-ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous adsorption and detection of five ZEAs in complex samples. The proposed method displayed favorable linearity, low limits of detection (0.003 ~ 0.018 µg kg-1), and good repeatability (2.37~10.4%). The developed method has been applied for real sample analysis, with recoveries of 81.27~90.26%. These results showed that Fe3O4@TAPB-Tp has a good application potential for the adsorption of ZEAs in food samples. Magnetic covalent organic framework nanocomposite (Fe3O4@TAPB-Tp) were quickly fabricated at mild conditions and used as effective adsorbent for magnetic solid-phase extraction of zearalenone and its derivatives (ZEAs) from food samples prior to ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis.


Assuntos
Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Micotoxinas/análise , Zearalenona/análise , Adsorção , Animais , Derivados de Benzeno/química , Cromatografia Líquida de Alta Pressão , Ovos/análise , Contaminação de Alimentos/análise , Limite de Detecção , Fenômenos Magnéticos , Leite/química , Micotoxinas/química , Micotoxinas/isolamento & purificação , Nanocompostos/química , Floroglucinol/análogos & derivados , Floroglucinol/química , Polimerização , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem , Zea mays , Zearalenona/análogos & derivados , Zearalenona/isolamento & purificação
12.
Mikrochim Acta ; 187(9): 503, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32812169

RESUMO

A novel magnetic dual-template molecularly imprinted polymer (DMIP) was prepared with methyl-parathion and quinalphos as templates. For comparison, a series of single-template polymers with only methyl-parathion (MPMIP) or quinalphos (QPMIP) as template as well as a non-imprinted polymer (NIP) in the absence of the template, were synthesized using the same procedure of DMIP. The obtained MIPs were characterized by scanning electron microscopy(SEM), Fourier transform infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM), and X-ray diffraction (XRD). The properties including kinetic effect, thermodynamic effect, selectivity, and reusability of MIPs were investigated . Only DMIP possessed high affinity and good recognition for all twelve OPPs including quinalphos, isazophos, chlorpyrifos-methyl, chlorpyrifos, methidathion, triazophos, profenofos, fenthion, fenitrothion, methyl-parathion, parathion, and paraoxon in comparison to MPMIP, QPMIP, or NIP. Moreover, DMIP was used as magnetic solid phase extraction (MSPE) sorbent for the pre-concentration of twelve OPPs in cabbage samples. The developed DMIP-MSPE-GC-MS method showed high sensitivity, low LODs (1.62-13.9 ng/g), fast adsorption equilibrium (10 min), and acceptable spiked recoveries (81.5-113.4%) with relative standard deviations (RSD) in the range 0.05-7.0% (n = 3). The calibration plots were linear in the range 10-800 ng/mL with coefficients of determination (R2) better 0.99 for all twelve compounds. These results suggest that the DMIP is applicable for rapid determination and high throughput analysis of multi-pesticide residues. Graphical abstract.


Assuntos
Metil Paration/isolamento & purificação , Polímeros Molecularmente Impressos/química , Compostos Organotiofosforados/isolamento & purificação , Praguicidas/isolamento & purificação , Adsorção , Brassica/química , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Fenômenos Magnéticos , Nanopartículas de Magnetita/química , Metil Paration/química , Compostos Organotiofosforados/química , Extração em Fase Sólida/métodos
14.
J Sep Sci ; 41(14): 2993-3002, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29809316

RESUMO

A method for the determination of 22 phthalate esters in polystyrene food-contact materials has been established using ultraperformance convergence chromatography with tandem mass spectrometry. In this method, 22 phthalate esters were analyzed in <3.5 min on an ACQUITY Tours 1-AA column by gradient elution. The mobile phase, the compensation solvent, the flow rate of mobile phase, column temperature, and automatic back pressure regulator pressure were optimized, respectively. There was a good linearity of 20 phthalate esters with a range of 0.05-10 mg/L, diisodecyl phthalate and diisononyl phthalate were 0.25-10 mg/L, and the correlation coefficients of all phthalates were higher than 0.99 and those of 16 phthalates were higher than 0.999. The limits of detection and the limits of quantification of 15 phthalates were 0.02 and 0.05 mg/kg, meanwhile diallyl phthalate, diisobutyl phthalate, dimethyl phthalate, di-n-butyl phthalate, and di(2-ethylhexyl) phthalate were 0.05 and 0.10 mg/kg, and diisodecyl phthalate and diisononyl phthalate were 0.10 and 0.25 mg/kg. The spiked recoveries were in the range of 76.26-107.76%, and the relative standard deviations were in the range of 1.78-12.10%. Results support this method as an efficient alternative to apply for the simultaneous determination of 22 phthalate esters in common polystyrene food-contact materials.

15.
Phys Chem Chem Phys ; 19(33): 22494-22501, 2017 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-28808715

RESUMO

Surface modification is proved to be an effective strategy to improve the power density of lithium-ion batteries (LIBs) applied in electric vehicles. In this article, a protective modification layer (FeF3/LiF) is successfully deposited onto the surface of a low-cost cathode material, Li6/5[Fe1/10Ni3/20Mn11/20]O2, for realizing the improvement of ultrafast lithium storage. The reversible specific capacity and ultrahigh rate capability are effectively improved. The modified sample can achieve a higher reversible discharge specific capacity of 171.8 mA h g-1 at 0.2C. A discharge specific capacity of 150.4 mA h g-1 is delivered at 1C after 60 cycles. Even at 2C and 5C, the discharge specific capacities are still maintained at 135.7 and 124.5 mA h g-1. Notably, when charged and discharged at 20C, a discharge specific capacity of 73.4 mA h g-1 can be achieved after 200 cycles by the heterostructured Li-Fe-Ni-Mn-O cathode, almost twice that of the bare material. The good fast lithium storage capability can be ascribed to the effective suppression of interfacial side reactions, the conversion reaction from the FeF3 phase, and the harmonious coexistence of layered and spinel phases. The triple benefits from the heterostructured cathode provide a promising route for constructing advanced LIBs.

16.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 44(3): 323-8, 2015 05.
Artigo em Zh | MEDLINE | ID: mdl-26350014

RESUMO

OBJECTIVE: To investigate the effects of extremely low frequency electromagnetic field (ELF-EMF) on human osteosarcoma cells and its mechanisms. METHODS: Human osteosarcoma MG-63 cells were exposed to 50 Hz,1 mT ELF-EMF for 1, 2 and 3 h in vitro, with or without pretreatment by reactive oxygen species (ROS) inhibitor N acetylcysteine (NAC) or p38MAPK inhibitor SB203580. The proliferation of MG-63 cells was determined by MTT method; the apoptosis rate and ROS level in MG-63 cells were detected by flow cytometry. The expression of p38MAPK in MG-63 cells was determined by Western blotting. RESULTS: ELF-EMF decreased the viability of MG-63 cells, inhibited cell growth, induced cell apoptosis and increased the level of ROS significantly. The apoptosis rate declined significantly after treatment with ROS inhibitor NAC or p38MAPK inhibitor SB203580. After exposure to ELF-EMF, p38MAPK in MG-63 cells was activated, and the phosphorylation level was also inhibited after treatment with NAC. CONCLUSION: ELF-EMF can induce the apoptosis of MG-63 cells. Increased ROS and p38MAPK activation may be involved in the mechanism.


Assuntos
Apoptose , Campos Eletromagnéticos , Osteossarcoma/patologia , Estresse Oxidativo , Acetilcisteína , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Imidazóis , Fosforilação , Piridinas , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
17.
Front Plant Sci ; 15: 1276799, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38362453

RESUMO

To address the problem that the low-density canopy of greenhouse crops affects the robustness and accuracy of simultaneous localization and mapping (SLAM) algorithms, a greenhouse map construction method for agricultural robots based on multiline LiDAR was investigated. Based on the Cartographer framework, this paper proposes a map construction and localization method based on spatial downsampling. Taking suspended tomato plants planted in greenhouses as the research object, an adaptive filtering point cloud projection (AF-PCP) SLAM algorithm was designed. Using a wheel odometer, 16-line LiDAR point cloud data based on adaptive vertical projections were linearly interpolated to construct a map and perform high-precision pose estimation in a greenhouse with a low-density canopy environment. Experiments were carried out in canopy environments with leaf area densities (LADs) of 2.945-5.301 m2/m3. The results showed that the AF-PCP SLAM algorithm increased the average mapping area of the crop rows by 155.7% compared with that of the Cartographer algorithm. The mean error and coefficient of variation of the crop row length were 0.019 m and 0.217%, respectively, which were 77.9% and 87.5% lower than those of the Cartographer algorithm. The average maximum void length was 0.124 m, which was 72.8% lower than that of the Cartographer algorithm. The localization experiments were carried out at speeds of 0.2 m/s, 0.4 m/s, and 0.6 m/s. The average relative localization errors at these speeds were respectively 0.026 m, 0.029 m, and 0.046 m, and the standard deviation was less than 0.06 m. Compared with that of the track deduction algorithm, the average localization error was reduced by 79.9% with the proposed algorithm. The results show that our proposed framework can map and localize robots with precision even in low-density canopy environments in greenhouses, demonstrating the satisfactory capability of the proposed approach and highlighting its promising applications in the autonomous navigation of agricultural robots.

18.
J Hazard Mater ; 472: 134321, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38723478

RESUMO

It is challenging to prepare sample pretreatment materials with simple use, strong selectivity and satisfactory enrichment performance. In this study, the antibody (3D4) that can specifically recognize zearalenone (ZEN) and its metabolites was immobilized on the surface of gold-coated magnetic Fe3O4 nanoparticles (GMN) by streptavidin (SA)-biotin interaction using GMN as the substrate and our designed four-arm PEG derivative (HS-4ARMPEG10K-(CM)3) as the linker. The immunomagnetic nanoparticles (GMN-4ARMPEG10K-SA-3D4) prepared by this strategy can achieve rapid enrichment (only 5 min) of analytes directly in the matrix, and higher enrichment capacity compared with the previous immunomagnetic particles. The sensitive and accurate analysis of ZEN and its metabolites can be achieved coupled with HPLC-MS/MS. The LODs and LOQs were 0.02-0.05 µg/kg and 0.05-0.10 µg/kg, respectively. The recoveries were 84.13%-112.67%, and the RSDs were 1.09%-9.39%. The method can provide a powerful tool for highly sensitive and rapid monitoring of mycotoxins in complex matrices due to its' strong selectivity and resistance to matrix interference.


Assuntos
Polietilenoglicóis , Zearalenona , Zearalenona/química , Zearalenona/análise , Zearalenona/metabolismo , Polietilenoglicóis/química , Ouro/química , Separação Imunomagnética , Nanopartículas de Magnetita/química , Limite de Detecção , Anticorpos Imobilizados/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem
19.
Food Chem ; 461: 140857, 2024 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-39151346

RESUMO

The thermal-responsive magnetic molecularly imprinted polymer (TrMMIP) sorbent was synthesized by surface imprinting method, and then used for magnetic solid-phase extraction (MSPE) and subsequent integrated into the ion source for elution and ionization. The shrinking-strength states change of the thermal-responsive polymer chain on TrMMIP alters the wettability of the sorbent when the working temperature crosses the lower critical solution temperature (LCST) of the polymer, and thus affects its behavior of in the extraction and clean-up process. The targeted analytes could be effectively extracted due to the high selectivity of MIPs and well dispersibility of polymer chain under the open state. Additionally, a hydrophilic polymer chain wrapped on the sorbent surface further protected target substances from co-elution during cleanup. Analytical methods for sulfonamide antibiotics (SAs) detection in complex food samples (milk, honey, fish) were developed, demonstrating potential for rapid and sensitive SAs analysis in diverse food and biological samples.


Assuntos
Antibacterianos , Contaminação de Alimentos , Mel , Interações Hidrofóbicas e Hidrofílicas , Leite , Polímeros Molecularmente Impressos , Extração em Fase Sólida , Sulfonamidas , Contaminação de Alimentos/análise , Antibacterianos/análise , Antibacterianos/química , Polímeros Molecularmente Impressos/química , Leite/química , Extração em Fase Sólida/instrumentação , Extração em Fase Sólida/métodos , Animais , Mel/análise , Sulfonamidas/química , Sulfonamidas/análise , Impressão Molecular , Peixes , Polímeros/química , Adsorção , Espectrometria de Massas
20.
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA