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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119513, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33571738

RESUMO

As a special carrier of traditional Chinese culture, baijiu is rich in terms of types and ingredients. Its quality analysis and control are always important and complex issues that urgently need reliable evaluation methods. In this study, four different modified CdTe quantum dots (QDs) were used to characterize their sensing performance to various baijiu. A sensor array was then constructed through the complementary properties of differential fluorescence signals. To achieve an accurate and rapid evaluation of different baijiu types, a linear discriminant analysis (LDA) was introduced to extract and process spectral information. And the array was able to distinguish commercial baijiu samples with different aroma-types, brands, qualities and storage years with a recognition rate of 100%. In addition, according to the heat map, the organic acids in baijiu were shown to be the main components causing the fluorescence change through electron transfer (hydrogen bond) and resonance energy transfer among QDs and acids. Furthermore, using the partial least squares regression (PLSR) model, five representative organic acids were accurately quantified with a quantitative range of 10 µmol/L-80 µmol/L with a high selectivity. This QDs fluorescence sensing strategy provides an accurate, simple, and fast baijiu sensing method, which provides a potential use for on-line baijiu monitoring.

2.
Sci Adv ; 7(5)2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33571112

RESUMO

Endothelial cell injury leading to microvascular rarefaction is a characteristic feature of chronic kidney disease (CKD). However, the mechanism underlying endothelial cell dropout is poorly defined. Here, we show a central role of the extracellular microenvironment in controlling endothelial cell survival and proliferation in CKD. When cultured on a decellularized kidney tissue scaffold (KTS) from fibrotic kidney, endothelial cells increased the expression of proapoptotic proteins. Proteomics profiling identified fibrillin-1 (FBN1) as a key component of the fibrotic KTS, which was up-regulated in animal models and patients with CKD. FBN1 induced apoptosis of endothelial cells and inhibited their proliferation in vitro. RNA sequencing uncovered activated integrin αvß6/transforming growth factor-ß signaling, and blocking this pathway abolished FBN1-triggered endothelial injury. In a mouse model of CKD, depletion of FBN1 ameliorated renal fibrotic lesions and mitigated vascular rarefaction. These studies illustrate that FBN1 plays a role in mediating vascular rarefaction by orchestrating a hostile microenvironment for endothelial cells.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33470491

RESUMO

Converting CO 2 and H 2 O into carbon-based fuel by IR light is a tough task. Herein, compared with other single-component photocatalysts, the most efficient IR-light-driven CO 2 reduction is achieved by an element-doped ultrathin metallic photocatalyst-Ni-doped CoS 2 nanosheets (Ni-CoS 2 ). The evolution rate of CH 4 over Ni-CoS 2 is up to 101.8 µmol g -1 h -1 . The metallic and ultrathin nature endow Ni-CoS 2 with excellent IR light absorption ability. The PL spectra and Arrhenius plots indicate that Ni atoms could facilitate the separation of photo-generated carriers and the decrease of the activation energy. Moreover, in situ FTIR, DFT calculations, and CH 4 -TPD reveal that the doped Ni atoms in CoS 2 could effectively depress the formation energy of the *COOH, *CHO and desorption energy of CH 4 . This work manifests that element doping in atomic level is a powerful way to control the reaction intermediates, providing possibilities to realize high-efficiency IR-light-driven CO 2 reduction.

4.
Food Chem ; 346: 128923, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33401087

RESUMO

Mercury ions and thiophanate methyl (TM), are common contaminants present in the environment and food products. These contaminants cause neurovirulence and carcinogenicity effect on the human body. Herein, thioctic acid-carbon dots (SCDs) was synthesized and applied in a fluorescent "turn-off-on" probe to detect Hg2+ and TM. The presence of other common metal ions and pesticides did not affect the response of the developed sensor. Further investigation revealed that the fluorescent "turn-off-on" model were static, wherein the "turn-off" was induced by an electron transfer effect, while the "turn-on" was caused by the formation of TM-Hg complexes. Under optimal conditions, the fluorescence sensor method exhibited limits of detection as low as 33.3 nmol/L and 7.6 nmol/L for Hg2+ and TM, respectively. The developed sensor was designed to detect Hg2+ and TM in real tap water, grape juice and Citri Reticulatae Pericarpium (CRP) water samples.

5.
Mikrochim Acta ; 188(1): 27, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404824

RESUMO

Caffeine naturally occurs in tea and cocoa, which is also used as an additive in beverages and has pharmacological effects such as refreshing, antidepressant, and digestion promotion, but excessive caffeine can cause harm to the human body. In this work, based on the specific response between nano zinc 5, 10, 15, 20-tetra(4-pyridyl)-21H-23H-porphine (nano ZnTPyP)-CdTe quantum dots (QDs) and caffeine, combined with chemometrics, a visual paper-based sensor was constructed for rapid and on-site detection of caffeine. The fluorescence of QDs can be quenched by nano ZnTPyP. When caffeine is added to the system, it can pull nano ZnTPyP off the surface of the QDs to achieve fluorescence recovery through electrostatic attraction and nitrogen/zinc coordination. The detection range is 5 × 10-11~3 × 10-9 mol L-1, and the detection limit is 1.53 × 10-11 mol L-1 (R2 = 0.9990) (S/N = 3). The paper-based sensor constructed exhibits good results in real samples, such as tea water, cell culture fluid, newborn bovine serum, and human plasma. Therefore, the sensor is expected to be applied to the rapid instrument-free detection of caffeine in food and biological samples.Graphical abstract.

6.
J Org Chem ; 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33267579

RESUMO

The NaIO4-mediated sequential iodination/amidation reaction of N-alkyl quinolinium iodide salts has been first developed. This cascade process provides an efficient way to rapidly synthesize 3-iodo-N-alkyl quinolinones with high regioselectivity and good functional group tolerance. This protocol was also amenable to the isoquinolinium salts, thus providing a complementary method for preparing the 4-iodo-N-alkyl isoquinolinones.

7.
Huan Jing Ke Xue ; 41(12): 5336-5344, 2020 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-33374049

RESUMO

Based on data from industrial activities and environmental surveys in the six districts of Xiamen, the emission inventory of industrially sourced volatile organic compounds (VOCs) from eight industries in the six districts of Xiamen was calculated for 2019 by applying the emission factor analysis method. The spatial distribution pattern of VOC emission intensity in the six districts of Xiamen was analyzed. VOCs treatment technologies applied in the industries in the VOCs emission inventory were analyzed and countermeasures for improving VOC control were proposed based on the survey of the industries. The results showed that the total VOCs production and VOCs emission from industrial sources in Xiamen was 16027.88 t and 5514.58 t in 2019, respectively. Among them, the VOCs emission from Haicang, Tong'an, Xiang'an, and Jimei districts outside Xiamen Island were 1648.35, 2111.13, 667.52, and 750.48 t, respectively. Fewer VOC emissions from Xiamen Island were observed, which included 292.42 and 44.68 t from Huli and Siming districts, respectively. Except for the Huli District, the spatial distribution of emissions showed a spatial characteristic that the VOCs emission intensities outside Xiamen Island are higher than that of Xiamen Island. Among the eight industries in Xiamen, VOCs emissions were mainly from coating, printing, chemical, and rubber industries, which accounted for 51.21%, 20.18%, 13.63%, and 10.67%, respectively, of the total emissions. The analytic results of the VOCs waste gas disposal technique in Xiamen indicate that, from the perspective of source control, enterprises can effectively control the generation and emission of the VOCs at the source by using low (zero) raw materials. For the terminal disposal procedure, the actual disposal efficiency of UV photolysis/photocatalysis, low-temperature plasma, and biological methods are all lower than 80%, and that of the combined technique of adsorption and catalytic combustion, and the combustion method are both higher than 90%.

8.
Chem Soc Rev ; 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33174897

RESUMO

Imidazolium based receptors selectively recognize anions, and have received more and more attention. In 2006 and 2010, we reviewed the mechanism and progress of imidazolium salt recognition of anions, respectively. In the past ten years, new developments have emerged in this area, including some new imidazolium motifs and the identification of a wider variety of biological anions. In this review, we discuss the progress of imidazolium receptors for the recognition of anions in the period of 2010-2019 and highlight the trends in this area. We first classify receptors based on motifs, including some newly emerging receptors, as well as new advances in existing receptor types at this stage. Then we discuss separately according to the types of anions, including ATP, GTP, DNA and RNA.

9.
J Sci Food Agric ; 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33063338

RESUMO

BACKGROUND: The quality of tea is influenced by numerous factors, especially l-theanine, which is one of the important markers used to evaluate the sweetness and freshness of tea. Sensitive, rapid, and accurate detection of l-theanine is therefore useful to identify the grade and quality of tea. RESULTS: A high-sensitivity, paper-based fluorescent sensor combined with chemometrics was established to detect l-theanine in tea water based on CdTe quantum dots / corn carbon dots and nano tetra pyridel-porphine zinc (ZnTPyP). To verify the reliability of this method, fluorescence spectra and fluorescence-visualized paper-based sensors were compared. The fluorescence spectrum method demonstrated a linear range of 1 to 10 000 nmol L-1 and a limit of detection (LOD) of 0.19 nmol L-1 . In the fluorescence-visualized paper-based sensors there was a linear range of 10-1000 nmol L-1 , and the LOD was 10 nmol L-1 . Partial least squares discriminant analysis (PLSDA) and partial least squares regression analysis (PLSR) were used successfully to determine l-theanine accurately in tea water with this approach. The accuracy of the PLSDA model was 100% both in the training set and the predicting set, and the correlation coefficient between the actual concentration and the predicted concentration was greater than 0.9997 in the PLSR model. CONCLUSION: This fluorescence-visualized paper-based sensor, combined with chemometrics, could be applied efficiently to the practical analysis of tea water samples, which provides a new idea to ensure the flavor and quality of tea. © 2020 Society of Chemical Industry.

10.
Biomed Res Int ; 2020: 2854186, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33015160

RESUMO

Objectives: To evaluate the role of short-term low-dose glucocorticoids in mild COVID-19 patients. Methods: We conducted a retrospective, cross-sectional, single-center study in Kunming, China. A total of 33 mild COVID-19 cases were divided into two treatment groups (with and without glucocorticoids, methylprednisolone, were used in this setting), and the absolute value of peripheral blood lymphocyte count; CD3+, CD4+, and CD8+ T cell counts; and the time to achieve negative transformation of a nucleic acid pharyngeal swab were recorded. Peripheral blood lymphocyte and T cell counts were compared between the treatment group and 25 healthy individuals. At the point of time when there was a 50% accumulation conversion rate (positive to negative nucleic acid on pharyngeal swab), and the nucleic acid turned negative in half of the patients in two groups, the peripheral blood lymphocyte and T cell counts were compared between treatment groups. Results: The mean cumulative time for the 50% negative conversion rate of the nucleic acid in the pharyngeal swab was 17.7 ± 5.1 days and 13.9 ± 5.4 days in the glucocorticoid group and the nonglucocorticoid group, respectively. The absolute peripheral blood lymphocyte count and the T cell subset count in the glucocorticoid group were lower than those in the nonglucocorticoid group. When the nucleic acid turned negative in half of the patients, the absolute value of peripheral blood lymphocyte count and CD4+ T cells of the glucocorticoid group and the nonglucocorticoid group was not significantly different; the CD3+ and CD8+ T cells in the glucocorticoid group were lower than those in the nonglucocorticoid group. The absolute peripheral blood lymphocyte count, CD3+ T cells, and CD4+ T cells in the glucocorticoid group were lower than those of the healthy group during the whole disease period, and CD8+ T cells returned to normal at 19-21 days of the disease period. There was no significant difference between the nonglucocorticoid group and the healthy group for absolute peripheral blood lymphocyte and CD8+ T cells; moreover, CD3+ T cells and CD4+ T cells were lower in the nonglucocorticoid group than those in the healthy group from the day of admission to the 18th day and returned to normal at the period of 19-21 days. The absolute peripheral lymphocyte count (P = 0.048, effect size d = 0.727) and T cell subset count (CD3: P = 0.042, effect size d = 0.655; CD4: P < 0.01, effect size d = 0.599; and CD8: P = 0.034, effect size d = 0.550) in the nonglucocorticoid group were higher than those in the glucocorticoid group, and the difference between the groups was statistically significant. Conclusions: This study found that the use of short-term, low-dose glucocorticoids does not negatively influence the clinical outcome, without affecting the final clearance of viral nucleic acid in mild COVID-19 patients.


Assuntos
Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , Glucocorticoides/administração & dosagem , Pneumonia Viral/tratamento farmacológico , Adolescente , Adulto , Betacoronavirus/isolamento & purificação , Criança , China/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Estudos Transversais , Feminino , Humanos , Contagem de Linfócitos , Masculino , Metilprednisolona/administração & dosagem , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Estudos Retrospectivos , Subpopulações de Linfócitos T/imunologia , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
11.
Mol Cell Proteomics ; 19(12): 2030-2046, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32963032

RESUMO

Sepsis-induced acute kidney injury (S-AKI) is the most common complication in hospitalized and critically ill patients, highlighted by a rapid decline of kidney function occurring a few hours or days after sepsis onset. Systemic inflammation elicited by microbial infections is believed to lead to kidney damage under immunocompromised conditions. However, although AKI has been recognized as a disease with long-term sequelae, partly because of the associated higher risk of chronic kidney disease (CKD), the understanding of kidney pathophysiology at the molecular level and the global view of dynamic regulations in situ after S-AKI, including the transition to CKD, remains limited. Existing studies of S-AKI mainly focus on deriving sepsis biomarkers from body fluids. In the present study, we constructed a mid-severity septic murine model using cecal ligation and puncture (CLP), and examined the temporal changes to the kidney proteome and phosphoproteome at day 2 and day 7 after CLP surgery, corresponding to S-AKI and the transition to CKD, respectively, by employing an ultrafast and economical filter-based sample processing method combined with the label-free quantitation approach. Collectively, we identified 2,119 proteins and 2950 phosphosites through multi-proteomics analyses. Among them, we identified an array of highly promising candidate marker proteins indicative of disease onset and progression accompanied by immunoblot validations, and further denoted the pathways that are specifically responsive to S-AKI and its transition to CKD, which include regulation of cell metabolism regulation, oxidative stress, and energy consumption in the diseased kidneys. Our data can serve as an enriched resource for the identification of mechanisms and biomarkers for sepsis-induced kidney diseases.

12.
Mol Med Rep ; 22(4): 2723-2732, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32945458

RESUMO

Thyroid carcinoma (THCA) is a malignant tumor of the endocrine system. Previous studies have revealed the vital roles of microRNAs (miRNAs/miRs) in THCA procession. The present study aimed to explore the effects of miR­15b­5p on the progression of THCA and its targeting mechanism. The data of THCA and healthy samples were firstly collected from starbase2.0 and used to analyze the relationship of miR­15b­5p with THCA. Dual­luciferase assay was performed to detect the direct interaction between miR­15b­5p and the predicted target gene GDP dissociation inhibitor 2 (GDI2). The effects of miR­15b­5p and GDI2 on the overall survival of patients with THCA were analyzed using Kaplan­Meier analysis with log rank test. Cell Counting Kit­8 and Transwell assays were conducted to assess the impacts of miR­15b­5p and GDI2 on the proliferation and invasion of THCA cells. Reverse transcription­quantitative PCR and western blot analyses were performed to analyze the expression levels of the related miRNAs and proteins, respectively. miR­15b­5p was found to be downregulated both in THCA tissues and cells, and the low expression of miR­15b­5p was associated with the short overall survival time of patients. Moreover, the upregulation or downregulation of miR­15b­5p could inhibit or enhance the proliferation and invasion of THCA cells, respectively. miR­15b­5p reduced the protein expression levels of matrix metalloproteinase (MMP)2 and MMP9, which were related to cell invasion. Furthermore, GDI2, which was enhanced in THCA and related to the poor prognosis of patients with THCA, was identified as the target gene of miR­15b­5p and negatively regulated by miR­15b­5p. Additional experiments demonstrated that GDI2 overexpression could significantly reduce the antitumor effect of miR­15b­5p and its inhibitory action on the expression levels of MMP2 and MMP9. Thus, the results indicated a potential tumor suppressive role of miR­15b­5p in THCA, which was mainly exerted by targeting GDI2 and modulating MMP2 and MMP9. These findings will increase the understanding on the pathogenesis of THCA and provide novel candidates for THCA therapy.

13.
Org Lett ; 22(18): 7108-7112, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32857522

RESUMO

A highly efficient and regioselective direct C-H trifluoromethylation of pyridine based on an N-methylpyridine quaternary ammonium activation strategy has been developed. A variety of trifluoromethylpyridines can be obtained in good yield and excellent regioselectivity by treating the pyridinium iodide salts with trifluoroacetic acid in the presence of silver carbonate in N,N-dimethylformamide. The protocol features good functional group compatibility, easily available starting materials, and operational simplicity. Controlled experiments showed that the reaction may involve a nucleophilic trifluoromethylation mechanism.

14.
Exp Mol Pathol ; 116: 104518, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32791063

RESUMO

BACKGROUND/AIMS: Long noncoding RNA (lncRNA) is a large and diverse class of RNA molecules, and has received widespread attention for its role in the regulation of various biological processes, including stem cell transformation, neurological disease, and tumorigenesis. However, the role of lncRNA in renal fibrosis remains unclear. METHODS: We investigated the expression of lncRNA-GAS5 by quantitative real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization in chronic kidney disease (CKD) by designing both in vivo and in vitro experiments. With over-expression of GAS5 or knockdown GAS5, miR-21 and its downstream target genes were tested using quantitative real-time PCR or western blots. Mutants of miR-21 were designed and transfected in cells. GAS5 in the plasma and urine of patients with CKD was measured by quantitative real-time PCR. RESULTS: In normal rats, GAS5 was predominantly expressed in renal tubular epithelial cells. GAS5 induction was significantly reduced in obstructive kidneys at 7 days after unilateral ureteral obstruction. In vitro, GAS5 was inhibited in cultured normal rat renal proximal tubular cells (NRK-52E) after incubation with transforming growth factor ß at 24 h. Ectopic over-expression of GAS5 repressed extracellular matrix (ECM) levels such as collagen type III and fibronectin 1. Conversely, knockdown GAS5 augmented ECM accumulation in NRK-52E cells. GAS5 suppressed miR-21 activity in a direct and mechanistic manner. It subsequently turned off the expression of miR-21 downstream target genes, matrix metallopeptidase 2 and 9, which resulted in excessive ECM synthesis and deposition. Of note, plasma GAS5 was positively correlated with estimated glomerular filtration rate levels in CKD patients with different etiologies while urine GAS5 was negatively correlated. CONCLUSION: Activation of lncRNA-GAS5 attenuates kidney fibrosis by modulating miR-21 activity and may serve as a surrogate biomarker in monitoring CKD progression.

15.
BMJ Open ; 10(7): e031580, 2020 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-32665340

RESUMO

OBJECTIVE: This study aims to test a Chinese cross-cultural adaptation of the English version of the Person-Centred Care Assessment Tool (P-CAT) and evaluate its psychometric properties. DESIGN: P-CAT was translated/back-translated using established procedures before the psychometric evaluation of the Chinese version was made. SETTING: Two hospitals covering urban and suburban areas of Kunming in the Yunnan province of China. PARTICIPANTS: 152 female hospital staff completed the survey. MAIN OUTCOME MEASURES: Construct validity and reliability, including internal consistency and test-retest reliability, were assessed among a sample of hospital staff. RESULTS: The factor analysis resulted in a two-component solution that consisted of two subscales. The corrected item-total correlations for all of the items ranged from 0.14 to 0.44, with six items not meeting the cut-off level for item-total correlation (>0.3). The Chinese P-CAT demonstrated strong reliability, with a Cronbach's alpha of 0.91-0.94 for the scales and a test-retest reliability coefficient of 0.88 for the overall scale scores. The intraclass correlation was 0.92 (95% CI 0.90 to 0.95). CONCLUSION: P-CAT appears to be a promising measure for evaluating staff perceptions of person-centredness in Chinese hospital environments. The results show that P-CAT can be a useful tool for improving the quality of healthcare in terms of person-centred care in the Chinese context.

16.
Org Lett ; 22(15): 6107-6111, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32678611

RESUMO

The first I2-mediated synthesis of 2-formylpyrroles from pyridinium salts is reported. This protocol enables the synthesis of diversely substituted 2-formylpyrroles in good yields under operationally simple conditions. The detailed mechanistic studies reveal that the reaction proceeds via a novel H2O-triggered ring opening of the pyridinium salt and a subsequent intramolecularly nucleophilic addition sequence.

17.
Med Sci Monit ; 26: e923726, 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32599603

RESUMO

BACKGROUND Kupffer cells and natural killer (NK) cells has been identified as contributing factors in the pathogenesis of hepatitis, but the detailed mechanism of these cell types in the pathogenesis of primary biliary cholangitis (PBC) is poorly understood. MATERIAL AND METHODS In this study, polyinosinic: polycytidylic acid (poly I: C), 2-octynoic acid-bovine serum albumin (2OA-BSA) and Freund's adjuvant (FA) were injected to establish a murine PBC model, from which NK cells and Kupffer cells were extracted and isolated. The cells were then co-cultivated in a designed culture system, and then NK group 2, member D (NKG2D), retinoic acid early inducible-1 (RAE-1), F4/80, and cytokine expression levels were detected. RESULTS The results showed close crosstalk between Kupffer cells and NK cells. PBC mice showed increased surface RAE-1 protein expression and Kupffer cell cytokine secretion, which subsequently activated NK cell-mediated target cell killing via NKG2D/RAE-1 recognition, and increased inflammation. NK cell-derived interferon-γ (IFN-γ) and Kupffer cell-derived tumor necrosis factor alpha (TNF-alpha) were found to synergistically regulate inflammation. Moreover, interleukin (IL)-12 and IL-10 improved the crosstalk between NK cells and Kupffer cells. CONCLUSIONS Our findings in mice are the first to suggest the involvement of the NKG2D/RAE-1 interaction and cytokines in the synergistic effects of NK and Kupffer cells in PBC.

18.
J Sep Sci ; 43(14): 2794-2803, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32386337

RESUMO

There are numerous articles published for geographical discrimination of tea. However, few research works focused on the authentication and traceability of Westlake Longjing green tea from the first- and second-grade producing regions because the tea trees are planted in a limited growing zone with identical cultivate condition. In this work, a comprehensive analytical strategy was proposed by ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based untargeted metabolomics coupled with chemometrics. The automatic untargeted data analysis strategy was introduced to screen metabolites that expressed significantly among different regions. Chromatographic features of metabolites can be automatically and efficiently extracted and registered. Meanwhile, those that were valuable for geographical origin discrimination were screened based on statistical analysis and contents in samples. Metabolite identification was performed based on high-resolution mass values and tandem mass spectra of screened peaks. Twenty metabolites were identified, based on which the two-way encoding partial least squares discrimination analysis was built for geographical origin prediction. Monte Caro simulation results indicated that prediction accuracy was up to 99%. Our strategy can be applicable for practical applications in the quality control of Westlake Longjing green tea.

19.
J Sci Food Agric ; 100(11): 4199-4207, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32374046

RESUMO

BACKGROUND: The fluorescence sensing method has been increasingly applied in food quality control because it is fast and sensitive. However, its application in quality evaluation is challenging. Using Citri Reticulatae Pericarpium (CRP; dried mandarin orange peel) as an example, we developed a simple and low-cost fluorescence sensing strategy based on nanoparticles combined with spectral splicing and chemometrics for quality evaluation. This method can recognize Citrus reticulata 'Chachi' (CRC) from other CRP cultivars and further identify the storage year. RESULTS: Nanogold particles and cadmium telluride quantum dots were selected as nanosensors and mixed with aqueous extracts of CRP separately to produce fluorescence quenching spectra. Then, a simple spectral splicing procedure was applied to obtain spliced spectra comprising different combinations of the self-fluorescence and fluorescence quenching spectra of CRP samples. With the aid of partial least-squares discriminant analysis, the new strategy achieved recognition rates of 100% in distinguishing CRC samples from other CRP samples, as well as recognition rates of 100% for the training set and 98.04% for the prediction set in the discrimination of the storage year of CRC. The recognition mechanism is dominated by interactions between the nanoparticles and the fluorescent components in the CRP samples, but other components also have concurrent effects. CONCLUSIONS: This novel fluorescence sensing strategy not only provides a new tool for the quality evaluation of CRC but also has good prospects for the authentication and traceability of other foods and herbs. Crucially, the developed method is convenient, simple and effective. © 2020 Society of Chemical Industry.

20.
J Sci Food Agric ; 100(12): 4464-4473, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32399965

RESUMO

BACKGROUD: Pesticides are widely used to control insect infestation and weeds in agriculture. However, concerns about the pesticide residues in agricultural products have been raised in recent years because of public interest in health and food quality and safety. Thus, rapid, convenient, and accurate analytical methods for the detection and quantification of pesticides are urgently required. RESULTS: A nanohybrid system composed of gold nanoparticles (AuNPs) and tetrakis(N-methyl-4-pyridiniumyl) porphyrin (TMPyP) was used as an optical probe for the detection and quantification of five pesticides (Paraquat, Dipterex, Dursban, methyl thiophanate and Cartap). The method is based on the aggregation effect of pesticides on the carboxyl group modified by AuNPs. Subsequently, with the help of particle swarm optimization-optimized sample weighted least squares-support vector machine (PSO-OSWLS-SVM), all the pesticides could be successfully quantified. In addition, partial least squares discriminant analysis (PLS-DA) was applied and the five pesticides were satisfactorily recognized based on data array obtained from the ultraviolet visible (UV-visible) spectra of AuNP-TMPyP complex. Furthermore, the quantitative and qualitative analysis of the five pesticides could be also achieved in the complex real samples, in which all the relative standard deviations (RSDs) were less than 0.3‰ and all the linear absolute correlation coefficients were more than 0.9990. Furthermore, recognition rate of the training set and the prediction set based on multiplicative scatter correction (MSC), or second-order derivative (2nd derivative) UV-visible spectra in PLS-DA model could reach 100%. CONCLUSION: This method was successfully applied for the rapid and accurate determination of multicomponent pesticide residues in real food samples. © 2020 Society of Chemical Industry.

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