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1.
Foods ; 13(3)2024 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-38338633

RESUMO

Developing a fast and non-destructive methodology to identify the storage years of Coix seed is important in safeguarding consumer well-being. This study employed the utilization of hyperspectral imaging (HSI) in conjunction with conventional machine learning techniques such as support vector machines (SVM), k-nearest neighbors (KNN), random forest (RF), extreme gradient boosting (XGBoost), as well as the deep learning method of residual neural network (ResNet), to establish identification models for Coix seed samples from different storage years. Under the fusion-based modeling approach, the model's classification accuracy surpasses that of visible to near infrared (VNIR) and short-wave infrared (SWIR) spectral modeling individually. The classification accuracy of the ResNet model and SVM exceeds that of other conventional machine learning models (KNN, RF, and XGBoost). Redundant variables were further diminished through competitive adaptive reweighted sampling feature wavelength screening, which had less impact on the model's accuracy. Upon validating the model's performance using an external validation set, the ResNet model yielded more satisfactory outcomes, exhibiting recognition accuracy exceeding 85%. In conclusion, the comprehensive results demonstrate that the integration of deep learning with HSI techniques effectively distinguishes Coix seed samples from different storage years.

2.
IEEE Trans Med Imaging ; 43(1): 309-320, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37527299

RESUMO

The segmentation of blurred cell boundaries in cornea endothelium microscope images is challenging, which affects the clinical parameter estimation accuracy. Existing deep learning methods only consider pixel-wise classification accuracy and lack of utilization of cell structure knowledge. Therefore, the segmentation of the blurred cell boundary is discontinuous. This paper proposes a structural prior guided network (SPG-Net) for corneal endothelium cell segmentation. We first employ a hybrid transformer convolution backbone to capture more global context. Then, we use Feature Enhancement (FE) module to improve the representation ability of features and Local Affinity-based Feature Fusion (LAFF) module to propagate structural information among hierarchical features. Finally, we introduce the joint loss based on cross entropy and structure similarity index measure (SSIM) to supervise the training process under pixel and structure levels. We compare the SPG-Net with various state-of-the-art methods on four corneal endothelial datasets. The experiment results suggest that the SPG-Net can alleviate the problem of discontinuous cell boundary segmentation and balance the pixel-wise accuracy and structure preservation. We also evaluate the agreement of parameter estimation between ground truth and the prediction of SPG-Net. The statistical analysis results show a good agreement and correlation.


Assuntos
Endotélio Corneano , Células Epiteliais , Endotélio Corneano/diagnóstico por imagem , Entropia , Células Endoteliais , Processamento de Imagem Assistida por Computador
3.
Food Chem ; 440: 138209, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38104449

RESUMO

The dry roots of Pleuropterus multiflorus Thunb. (PM) have been traditionally utilized as functional foods and medicines China and various Asian countries. They are extensively cultivated in multiple provinces in China, with variations in prices and qualities. This study aims to investigate the regional characteristics of PM by 4 stable isotope ratios, 40 multielement and 16 functional compounds contents, using a total of 357 samples from 8 different geographical origins. Machine learning methods were developed to authenticating the geographical origins of PM, yielding the accuracy range from 94.44 % to 100 % in the test set. Notably, the protected designation of origin, Deqing PM, exhibited a high accuracy of 100 % in most models, A total of 30 significant prediction variables, encompassing 16 functional compounds, δ2H, 12 rare earth elements, and Cu, were identified. Additionally, the study identified altitude, high temperature, and dry or moisture index as the primary influenced environmental factors.


Assuntos
Isótopos , China , Ásia
4.
J Agric Food Chem ; 71(31): 11982-11992, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37523321

RESUMO

An integrated purification procedure through the LC-MS/MS-based molecular networking strategy combined with bioactive evaluation was first ushered for discovering bioactive ophiobolins from Bipolaris eleusines. Ophiobolins were mainly dispersed in five clusters, which were classified based on different ring systems and functional groups. Nine undescribed ophiobolins (1-6 and 9-11) and an undescribed natural product (8) along with two known analogs (7 and 12) were isolated in target. The undescribed structures were characterized by HR-ESI-MS, NMR spectra, and X-ray diffraction experiments. Compounds 3-12 exhibited strong phytotoxic effects on green foxtails by producing visible lesions, and compounds 1-10 and 12 displayed different levels of cytotoxic activities against cancer cell lines B16, Hep G2, and MCF-7, from which the possible structure-activity relationships were then suggested. The results have supported that bioactivity-guided molecular networking is an efficient strategy to expedite the discovery of undescribed bioactive natural products.


Assuntos
Sesterterpenos , Espectrometria de Massas em Tandem , Cromatografia Líquida , Sesterterpenos/farmacologia , Sesterterpenos/química , Estrutura Molecular
5.
Zhongguo Zhong Yao Za Zhi ; 48(8): 2020-2040, 2023 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-37282892

RESUMO

Codonopsis Radix is a traditional tonic medicine commonly used in China, which has the effects of strengthening the spleen and tonifying the lung, as well as nourishing blood and engendering liquid. The chemical constituents of Codonopsis species are mainly polyacetylenes, alkaloids, phenylpropanoids, lignans, terpenoids and saponins, flavonoids, steroids, organic acids, saccharides, and so on. Modern pharmacological studies showed that Codonopsis Radix also has a variety of pharmacological effects such as enhancing body immunity, protecting gastrointestinal mucosa and resisting ulcers, promoting hematopoietic function, regulating blood sugar, and delaying aging. In this paper, the chemical constituents of Codonopsis species and the pharmacological effects of Codonopsis Radix were summarized, and on this basis, the quality markers of Codonopsis Radix were analyzed. It was predicted that lobetyolin, tangshenoside I, codonopyrrolidium A, and the oligosaccharides were the possible Q-markers of Codonopsis Radix. This paper will provide scientific references for the quality evaluation and profound research and the development of Codonopsis Radix.


Assuntos
Alcaloides , Codonopsis , Medicamentos de Ervas Chinesas , Medicina Tradicional , Raízes de Plantas
6.
PLoS One ; 18(4): e0277890, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37027422

RESUMO

It is necessary to ensure the ship's stability in container ship stowage and loading and unloading containers. This work aims to reduce the container dumping operation at the midway port and improve the efficiency of ship transportation. Firstly, the constraint problem of the traditional container ship stacking is introduced to realize the multi-condition mathematical model of the container ship, container, and wharf. Secondly, a Hybrid Genetic and Simulated Annealing Algorithm (HGSAA) model is proposed for the container stacking and loading stacking in the yard. The specific container space allocation and multi-yard crane adjustment scheme are studied. Finally, the effectiveness of the multi-condition container ship stowage model is verified by numerical experiments by changing the number of outbound containers, storage strategies, storage yards, and bridges. The experimental results show that the HGSAA mode converges to 106.1min at the 751st iteration. Of these, the non-loading and unloading time of yard bridge 1 is 3.43min. The number of operating boxes is 25. The non-loading and unloading time of yard bridge 2 is 3.2min, and the operating box volume is 25 boxes. The objective function of the genetic algorithm converges when it iterates to generation 903 and 107.9min. Among them, the non-loading and unloading time of yard bridge 1 is 4.1min. The non-loading and unloading time of yard bridge 2 is 3.1min. Therefore, the proposed HGSAA has a faster convergence speed than the genetic algorithm and can obtain relatively good results. The proposed container stacking strategy can effectively solve the specific container allocation and multi-yard crane scheduling problems. The finding provides a reference for optimizing container scheduling and improving shipping transportation efficiency.


Assuntos
Navios , Meios de Transporte , Algoritmos , Modelos Teóricos
7.
Chin Herb Med ; 15(1): 102-109, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36875447

RESUMO

Objective: Gentamicin (GM) is a commonly used aminoglycoside antibiotic, however, renal toxicity has limited its usage. The present study was designed to evaluate the ameliorative effect of Cistanche deserticola on GM-induced nephrotoxicity in rats. Methods: The nephrotoxicity in rats was induced by intraperitoneal administration of GM (100 mg/kg) for 10 consecutive days. Glomerular filtration rate, blood urea nitrogen, creatinine and kidney histopathology were detected to assess the GM-induced nephrotoxicity. The oxidative stress (catalase, superoxide dismutase, glutathione and malondialdehyde) was assessed. The inflammatory response (tumor necrosis factor-α, interleukin-6, myeloperoxidase and nuclear factor-kappa B) and apoptotic marker (Bax and Bcl-2) were also evaluated. Results: The results showed that water and 75% ethanol extracts of C. deserticola (named CDW and CDE, respectively) (100, 200 and 400 mg/kg) in combination with GM could recover the reduction of glomerular filtration rate and enhance the renal endogenous antioxidant capability induced by GM. The increase in the expression of renal inflammatory cytokines (tumor necrosis factor-α and interleukin-6), nuclear protein of nuclear factor-kappa B (p65) and the activity of myeloperoxidase induced by GM was significantly decreased upon CDW or CDE treatment. In addition, CDW or CDE treatment could decrease the Bax protein expression and increase the Bcl-2 protein expression in GM-induced nephrotoxicity in rats significantly. Conclusion: The study demonstrated that C. deserticola treatment could attenuate kidney dysfunction and structural damage in rats induced by GM through the reduction of inflammation, oxidative stress and apoptosis.

8.
J Chromatogr A ; 1685: 463642, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36395248

RESUMO

Codonopsis Radix (CR) is a plant that is important in the practice of traditional Chinese medicine (TCM). The Chinese Pharmacopoeia 2020 records dried roots prepared from three varieties of Campanulaceae plants under the designation CR ("Dang-shen" in Chinese), including Codonopsis pilosula (Franch.) Nannf (C. pilosula), Codonopsis pilosula Nannf.var.modesta (Nannf.) L81. T. Shen (C. pilosula var. modesta) and Codonopsis tangshen Oliv (C. tangshen). As major constituents of CR, oligosaccharides might contribute to its clinical efficacy except for other known active compounds, yet the differences in the oligosaccharide profiles of these three varieties of CR remain incompletely understood. In the present study, 135 samples from these different CR varieties were harvested, and oligosaccharide fingerprints for these samples were characterized via HPLC-ELSD, with 19 common peaks being matched. Oligosaccharides were further identified through the combination of electrospray ionization MS/MS (ESI-MS/MS) with nuclear magnetic resonance (NMR). Principal component analysis and linear discriminant analysis (LDA) approaches were then used to compare the oligosaccharide profiles of these three CR varieties. These analyses ultimately revealed that CR was compared with principal component analysis (PCA) and linear discriminant (LDA) methods. The analyses ultimately revealed that these CR samples contained high levels of inulin- and levan-type fructooligosaccharides (FOS), with variations in the relative levels of these FOS compounds among the three analyzed CR varieties. Through the combined analysis of oligosaccharide fingerprints and LDA results, it was possible to differentiate among these CR varieties, with an accurate classification rate of 96.3% and a cross-validation rate of 95.6%. Together, these results highlight a valuable approach to the classification and identification of different CR varieties.


Assuntos
Codonopsis , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem , Análise Multivariada , Oligossacarídeos
9.
Food Funct ; 13(15): 8143-8157, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35816111

RESUMO

Obesity has become a major health problem worldwide, linked to gut microbiota imbalance and chronic inflammation. This study aims to evaluate whether Codonopsis pilosula oligosaccharides (CPOs) can alleviate obesity and related metabolic complications in high-fat diet (HFD) induced obese mice. Male C57BL/6J mice were fed with a HFD for 16 weeks and treated daily with CPOs (500 mg kg-1). CPO supplementation decreased body weight and fat accumulation and improved glucose tolerance in HFD-fed mice. CPOs also reversed the effects of the HFD on inflammatory markers and improved macrophage infiltration. The results of gut microbiota analysis showed that CPOs could also regulate gut microbiota composition, significantly increasing the abundance of the beneficial bacteria Muribaculaceae spp., Alistipes and Clostridium and decreasing the abundance of the harmful bacteria Rikenella, Enterobacteriaceae spp., Collinsella and Megasphaera in HFD mice. Based on serum non-targeted metabolomics analysis, 20 key metabolites responding to CPO treatment were identified, and their biological functions were mainly related to tryptophan and bile acid metabolism. The results demonstrate that CPO supplementation can ameliorate HFD-induced obesity and obesity-related metabolic disorders. It can be used as a novel gut microbiota modulator to prevent HFD-induced gut dysbiosis.


Assuntos
Codonopsis , Microbioma Gastrointestinal , Animais , Dieta Hiperlipídica/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/metabolismo , Oligossacarídeos/efeitos adversos
10.
Sci Rep ; 12(1): 8133, 2022 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-35581226

RESUMO

In recent years, the safety of Codonopsis Radix (CR) has attracted considerable attention. Pesticide residues is an important index to evaluate the safety of CR. The purpose of this study was to monitor pesticide residues in 164 batches of CR in China and assess dietary risk assessment. Firstly, a combined method of QuEChERS-GC-MS/MS and QuEChERS-LC-MS/MS was established for determination of 155 pesticide residues in CR. Second, 155 Pesticide residues in 3 CR cultivars from Gansu, Shanxi, Hubei, Guizhou and Chongqing were determined by this method. Finally, the risk score of pesticide residues in CR was evaluated, and the dietary health risk was evaluated based on the pesticide residues in CR. The results demonstrated that one or more pesticide residues were detected in 39 batches (23.78%) of 164 batches of CR. Of the 155 pesticide residues, 20 were detected. The most frequently detected pesticide residue was dimethomorph with a detection rate of 5.49%. Risk scores showed that 6 pesticides were at higher risk. Risk assessment based on the hazard quotient/hazard index (HQ/HI) approach revealed that exposure to pesticide residues which detected in CR were far below levels that might pose a health risk.


Assuntos
Codonopsis , Resíduos de Praguicidas , Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Resíduos de Praguicidas/análise , Medição de Risco , Caramujos , Espectrometria de Massas em Tandem/métodos
11.
Sci Rep ; 12(1): 8549, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35595826

RESUMO

Multi-elemental analysis is widely used to identify the geographical origins of plants. The purpose of this study was to explore the feasibility of combining chemometrics with multi-element analysis for classification of Codonopsis Radix from different producing regions of Gansu province (China). A total of 117 Codonopsis Radix samples from 7 counties of Gansu province were collected. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of 28 elements (39 K, 24 Mg, 44Ca, 27Al, 137Ba, 57Fe, 23Na, 88Sr, 55Mn, 66Zn, 65Cu, 85Rb, 61Ni, 53Cr, 51 V, 7Li, 208Pb, 59Co, 75As, 133Cs, 71 Ga, 77Se, 205Tl, 114Cd, 238U, 107Ag, 4Be and 202Hg). Among macro elements, 39 K showed the highest level, whereas 23Na was found to have the lowest content value. Micro elements showed the concentrations order of: 88Sr > 55Mn > 66Zn > 85Rb > 65Cu. Among trace elements, 53Cr and 61Ni showed higher content and 4Be was not detected in all samples. Intra-regions differentiation was performed by principal component analysis (PCA), cluster analysis (CA) and supervised learning algorithms such as linear discriminant analysis (LDA), k-nearest neighbors (k-NN), support vector machines (SVM), and random forests (RF). Among them, the RF model performed the best with an accuracy rate of 78.79%. Multi-elemental analysis combined with RF was a reliable method to identify the origins of Codonopsis Radix in Gansu province.


Assuntos
Codonopsis , Oligoelementos , Quimiometria , China , Análise Discriminante , Caramujos , Oligoelementos/análise
12.
Biol Trace Elem Res ; 200(5): 2475-2485, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34383249

RESUMO

As a valuable medicine food homology plant, Codonopsis Radix has been widely used in China. This study aimed to analyze the content of nine potentially toxic elements in three Codonopsis Radix varieties and evaluate their health risks to the human body. In this study, a total of 147 samples were collected from five provinces in China. The content of nine potentially toxic elements (Al, Mn, Cu, Cr, Ni, As, Pb, Cd, and Hg) were determined by ICP-MS. Results showed that the average contents of Al, Mn, Cu, Cr, Ni, Pb, As, Cd, and Hg were 486.81, 30.30, 5.59, 1.38, 1.24, 0.40, 0.20, 0.16, and 0.11 mg/kg, respectively. The Codonopsis tangshen Oliv. samples from Hubei showed the highest contents of eight elements (Al, Mn, Cr, Ni, Pb, As, Cd, and Hg) among three varieties, and the highest Cu level was found in Codonopsis pilosula (Franch.) Nannf. samples from Shanxi. The content of toxic elements in three Codonopsis Radix varieties showed significant differences (p < 0.05). LDA models facilitated the identification of three Codonopsis Radix varieties with a 91.2% classification score and 89.1% prediction score. Further, when Codonopsis Radix was used as food or medicine, both the hazard quotient values for single element and the hazard index values for nine elements (0.87 for food and 0.84 for medicine) were far below one. The carcinogenic risk values for Pb in Codonopsis Radix when used as food or medicine were 1.14 × 10-6 and 5.51 × 10-8; the values for As were 4.80 × 10-5 and 4.98 × 10-6, respectively. It indicated that under the current consumption of Codonopsis Radix, the non-carcinogenic and carcinogenic risks from these potentially toxic elements were acceptable for consumers.


Assuntos
Codonopsis , Mercúrio , Metais Pesados , Poluentes do Solo , Cádmio/análise , China , Monitoramento Ambiental/métodos , Humanos , Chumbo/análise , Mercúrio/análise , Metais Pesados/análise , Medição de Risco , Caramujos , Poluentes do Solo/análise
13.
Food Funct ; 11(4): 3306-3315, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32227014

RESUMO

As an important edible traditional Chinese medicine, Codonopsis pilosula has good immunomodulation effects. This study focuses on C. pilosula oligosaccharides (CPO), which are the sweetness components of C. pilosula. CPO were obtained through systematic separation and purification (the yield is 14.3%), and the effect of CPO on the immunological activities of immunocompromised mice induced by cyclophosphamide (CTX) was evaluated. The results showed that CPO could increase immune organ indices, phagocytic index and immunoglobulin contents, stimulate the proliferation of splenic lymphocytes (coordinating with ConA and LPS), enhance the earlap swelling of the DTH reaction, promote the production of NO and cytokines (IL-2 and IFN-γ) and upregulate the expression of the corresponding mRNA. In addition, CPO upregulated the protein expression of phosphorylated p38, phosphorylated ERK1/2 and phosphorylated JNK, which indicated that CPO might exert immunomodulatory effects through the MAPK signaling pathway. These findings indicated that CPO are important immunomodulatory components in C. pilosula and could be developed as immunomodulators in medicine or functional food areas.


Assuntos
Codonopsis/química , Ciclofosfamida/farmacologia , Fatores Imunológicos/farmacologia , Terapia de Imunossupressão , Oligossacarídeos/farmacologia , Animais , Citocinas/metabolismo , Hospedeiro Imunocomprometido , Masculino , Medicina Tradicional Chinesa , Camundongos , Oligossacarídeos/química , Extratos Vegetais/farmacologia , Baço
14.
Int J Biol Macromol ; 120(Pt B): 1544-1550, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30248423

RESUMO

Two water-soluble polysaccharides named CPP1a and CPP1c were isolated from C. pilosula Nannf. var. modesta L.T.Shen by hot-water extraction and purified by graded alcohol precipitation and DEAE-52 cellulose column. The structure of CPP1c with higher yield has been characterized while its antitumor activities has not been elucidated. In this study, we firstly analyzed the chemical structure of CPP1a. The results of instrumental analysis combined with chemical analysis showed that CPP1a was composed of →1)- ß­l­Rhap­(4→, →1)- ß­Arap­(5→, →1)- ß­d­GalpA­(4→, →1)- ß­d­Galp­(6→, terminal­ß­d­Glcp in a molar ratio of 1:12:1:10:3 and its relative and absolute molecular weight were 1.01 × 105 Da and 1.03 × 105 Da respectively. Further, the cytotoxicity assay indicated that CPP1a and CPP1c were more sensitive to HepG2 cells than cervical carcinoma Hela cells and gastric carcinoma MKN45 cells. Both of CPP1a and CPP1c could influence cell morphology, inhibit the migration and induce apoptosis by affecting the G2/M phase of HepG2 cells. Preliminary mechanism studies confirmed that CPP1a and CPP1c could induce apoptosis through up-regulating the ratio of Bax/Bcl-2 and activating caspase-3. According to previous research, we might speculate that the reason for the stronger cytotoxicity and pro-apoptotic effect of CPP1c than that of CPP1a can be attributed to its high uronic acid content.


Assuntos
Carcinoma Hepatocelular/patologia , Codonopsis/química , Neoplasias Hepáticas/patologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Água/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , DNA Topoisomerases Tipo I/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HeLa , Células Hep G2 , Humanos , Diester Fosfórico Hidrolases/metabolismo , Solubilidade
15.
Int J Biol Macromol ; 104(Pt A): 1359-1369, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28600205

RESUMO

A pectic polysaccharide (named as CPP1c) extracted from Codonopsis pilosula was evaluated for its structural features and potential of immune-modulating activities in an aging mouse model of senescence accelerated mouse prone 8 (SAMP8) in vitro and in vivo. The relative molecular weight and the absolute molecular weight of CPP1c were 1.26×105Da and 1.49×105Da, respectively. Investigation of structural features by a combination of chemical and instrumental analysis showed CPP1c was composed of →1)-α-l-Rhap-(2,4→, →1)-α-l-Araf-(5→, →1)-α-d-Galp-(6→ and →1)-α-d-GalpA-(4→ in a molar ratio of 3:1:2:33. CPP1c could promote lymphocyte proliferation, modulate the percentage of CD4+, CD8+, CD28+ and CD152+ T cells and enhance the production of IL-2, TNF-α and IFN-γ. Moreover, PCR assay revealed CPP1c augmented the expressions of CD28, PI3K and p38MAPK mRNA, and the increase of protein expressions of the same genes was also confirmed by western blot analyses. In addition, CPP1c had the potential of promoting the homing of lymphocytes. Taking all factors into consideration, we deduced CPP1c might exert its immunostimulating potency via promoting T cell activation by TCR/CD28 signaling pathways.


Assuntos
Codonopsis/química , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Pectinas/química , Pectinas/farmacologia , Animais , Citocinas/metabolismo , Masculino , Metilação , Camundongos , Monossacarídeos/análise , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/metabolismo
16.
Mater Sci Eng C Mater Biol Appl ; 74: 515-524, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28254326

RESUMO

A novel lobetyolin electrochemical sensor based on a magnetic functionalized reduced graphene oxide/Nafion nanohybrid film has been introduced in this work. The magnetic functionalized reduced graphene oxide was characterized by fourier transform infrared spectroscopy, atomic force microscope, X-ray diffraction, transmission electron microscopy and thermogravimetric analysis. The scanning electron microscopy characterized the morphology and microstructure of the prepared sensors, and the electrochemical effective surface areas of the prepared sensors were also calculated by chronocoulometry method. The electrochemical behavior of lobetyolin on the magnetic functionalized reduced graphene oxide/Nafion nanohybrid modified glassy carbon electrode was investigated by cyclic voltammetry and differential pulse voltammetry in a phosphate buffer solution of pH6.0. The electron-transfer coefficient (α), electron transfer number (n), and electrode reaction rate constant (Κs) were calculated as 0.78, 0.73, and 4.63s-1, respectively. Under the optimized conditions, the sensor based on magnetic functionalized reduced graphene oxide/Nafion showed a linear voltammetric response to the lobetyolin concentration at 1.0×10-7 to 1.0×10-4mol/L with detection limit (S/N=3)of 4.3×10-8mol/L. The proposed sensor also displayed acceptable reproducibility, long-term stability, and high selectivity, and performs well for analysis of lobetyolin in real samples. The voltammetric sensor was successfully applied to detect lobetyolin in Codonopsis pilosula with recovery values in the range of 96.12%-102.66%.


Assuntos
Técnicas Eletroquímicas , Grafite/química , Magnetismo , Poli-Inos/análise , Técnicas Biossensoriais , Catálise , Codonopsis/química , Codonopsis/metabolismo , Eletrodos , Óxido Ferroso-Férrico/química , Polímeros de Fluorcarboneto/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Óxidos/química , Reprodutibilidade dos Testes , Termogravimetria , Difração de Raios X
17.
Biosens Bioelectron ; 88: 55-62, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27499382

RESUMO

A sensitively competitive electrochemical immunosensor for the detection of cortisol was successfully developed based on gold nanoparticles and magnetic functionalized reduced graphene oxide (AuNPs/MrGO). In order to construct the base of the immunosensor, the MrGO was initially fabricated by chemical cross-linking and used to modify the nafion pretreated glassy carbon electrode. Subsequently, the surface of electrode was modified by AuNPs via electrochemical deposition. A variety of cortisol (Cor) can be firmly loaded in the AuNPs/MrGO with large specific surface area and good bioactivity to construct the basic electrode (Cor/AuNPs/MrGO/Nafion@GCE), which was characterized by the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. Due to the cortisol on the surface of basic electrode and samples can competitively combine with the cortisol antibody labelled by horseradish peroxidase (HRP-Strept-Biotin-Ab). Finally, the detection signal of electrochemical immunosensor (HRP-Strept-Biotin-Ab-Cor/AuNPs/MrGO/Nafion@GCE) in the test liquid had negative correlations with the concentration of cortisol in samples. The AuNPs/MrGO with excellent electrical conductivity being applied, the electrochemical response of the immunosensor was immensely amplified. The immunosensor displayed excellent analytical performance for the detection of cortisol range from 0.1 to 1000ng/mL with a detection limit of 0.05ng/mL at 3σ. Moreover, compared the developed immunoassay with commercially available enzyme linked immunosorbent assay, the proposed method showed good precision, acceptable stability and reproducibility, indicating the immunosensor could be used for the sensitive, efficient and real-time detection of cortisol in real samples. Therefore, the present strategy provides a novel and convenient method for clinical determination of cortisol.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Ouro/química , Grafite/química , Hidrocortisona/sangue , Imãs/química , Nanopartículas Metálicas/química , Eletrodos , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Modelos Moleculares , Oxirredução , Óxidos/química , Reprodutibilidade dos Testes
18.
Sensors (Basel) ; 16(11)2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-27854324

RESUMO

Twelve GPS Block IIF satellites, out of the current constellation, can transmit on three-frequency signals (L1, L2, L5). Taking advantages of these signals, Three-Carrier Ambiguity Resolution (TCAR) is expected to bring much benefit for ambiguity resolution. One of the research areas is to find the optimal combined signals for a better ambiguity resolution in geometry-free (GF) and geometry-based (GB) mode. However, the existing researches select the signals through either pure theoretical analysis or testing with simulated data, which might be biased as the real observation condition could be different from theoretical prediction or simulation. In this paper, we propose a theoretical and empirical integrated method, which first selects the possible optimal combined signals in theory and then refines these signals with real triple-frequency GPS data, observed at eleven baselines of different lengths. An interpolation technique is also adopted in order to show changes of the AR performance with the increase in baseline length. The results show that the AR success rate can be improved by 3% in GF mode and 8% in GB mode at certain intervals of the baseline length. Therefore, the TCAR can perform better by adopting the combined signals proposed in this paper when the baseline meets the length condition.

19.
J Pharm Anal ; 6(2): 80-86, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29403966

RESUMO

An electrochemical method based on a directly electrochemically reduced graphene oxide (ERGO) film coated on a glassy carbon electrode (GCE) was developed for the rapid and convenient determination of rutin in plasma. ERGO was modified on the surface of GCE by one-step electro-deposition method. Electrochemical behavior of rutin on ERGO/GCE indicated that rutin underwent a surface-controlled quasi-reversible process and the electrochemical parameters such as charge transfer coefficient (α), electron transfer number (n) and electrode reaction standard rate constant (ks ) were 0.53, 2 and 3.4 s-1, respectively. The electrochemical sensor for rutin in plasma provided a wide linear response range of 4.70×10-7-1.25×10-5 M with the detection limit (s/n=3) of 1.84×10-8 M. The assay was successfully used to the pharmacokinetic study of rutin. The pharmacokinetic parameters such as elimination rate half-life (t1/2), area under curve (AUC), and plasma clearance (CL) were calculated to be 3.345±0.647 min, 5750±656.0 µg min/mL, and 5.891±0.458 mL/min/kg, respectively. The proposed method utilized a small sample volume of 10 µL and had no complicated sample pretreatment (without deproteinization), which was simple, eco-friendly, and time- and cost-efficient for rutin pharmacokinetic studies.

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