A LIBSVM quality assessment model for apple spoilage during storage based on hyperspectral data.

To assess the quality of apple samples during storage, this study proposes a spoilage benchmark based on hyperspectral data feature indicators and the Mahalanobis Distance (MD). Additionally, a quality assessment model was developed utilizing LIB Support Vector Machine (LIBSVM). Initially, a spoilage benchmark for apple samples was preliminarily established using hyperspectral data feature indicators, including the color feature, texture feature of sample hyperspectral images, and wavelet packet energy (WPE) of sample spectral information. Secondly, this study utilized the successive projection algorithm (SPA) to extract three wavelength sets sensitive to changes in the three indicators. This process resulted in the identification of 20 feature wavelengths based on the three sets. Subsequently, the spoilage benchmark for apple samples was verified using MD based on the spectral information of feature wavelengths. Ultimately, utilizing pre-processed spectral information enhanced by the sliding window algorithm and spoilage benchmark, the LIBSVM quality assessment model was developed, achieving a training set accuracy of 99.94% and a test set accuracy of 99.66%. Moreover, to assess the strength and applicability of the model, a verification experiment was conducted using a different set of apple samples. The training set accuracy was 100% and the test set accuracy was 99.83%. These findings indicate that the model can effectively indicate the level of spoilage in each sample during long-term storage. This also serves to demonstrate the robustness of the model and the effectiveness of the spoilage benchmark determination method during apple storage.

Innovative hybrid strategy for quality improvement of Goji tea: ultrasonic-ethyl oleate pretreatment combined with heat pump drying.

BACKGROUND: Goji berries, renowned for their nutritional benefits, are traditionally dried to extend shelf life and preserve quality. However, conventional drying methods often result in uneven drying, color loss and reduced rehydration capacity. This study investigates an innovative hybrid strategy combining ultrasonic-ethyl oleate (US+AEEO) pretreatment with heat pump drying (HPD) to enhance the drying process of Goji berries. RESULTS: Fresh Goji berries underwent US+AEEO pretreatment, which significantly disrupted the waxy layer, enhancing drying efficiency and water infiltration during rehydration. Compared to freeze drying (FD), HPD combined with US+AEEO pretreatment resulted in higher retention of total polyphenol content (TPC) and total flavonoid content (TFC) in the Goji soaking soup. Specifically, the HPD-US+AEEO samples exhibited the highest TPC and TFC levels, significantly outperforming FD samples. Additionally, the DPPH and ABTS antioxidant assays demonstrated higher scavenging activities in HPD-US+AEEO samples. The rehydration kinetics revealed that HPD samples had a superior rehydration rate and final moisture content compared to FD samples. Low-field nuclear magnetic resonance and magnetic resonance imaging analyses confirmed enhanced water distribution and higher mobility in HPD-US+AEEO samples. Scanning electron microscopy indicated a more porous structure in US+AEEO-treated samples, facilitating better water absorption and functional component retention. CONCLUSION: The combination of US+AEEO pretreatment with HPD significantly improves the drying process of Goji berries, enhancing nutrient retention, color preservation and rehydration properties. This innovative drying method offers a promising solution for producing high-quality dried Goji berries, benefiting both the food industry and health-conscious consumers. © 2024 Society of Chemical Industry.

A fluorescent aptasensor for highly sensitive and selective detection of carcinoembryonic antigen based on upconversion nanoparticles and WS2 nanosheets.

A highly sensitive fluorescent aptasensor for carcinoembryonic antigen (CEA) was developed by employing upconversion nanoparticles (UCNPs) as an energy donor and WS2 nanosheets as an energy acceptor, respectively. Polyacrylic acid (PAA) modified NaYF4:Yb/Er UCNPs and an amine modified CEA aptamer were linked together by a covalent bond. Owing to the physical adsorption between WS2 nanosheets and the CEA aptamer, the UCNPs-aptamer was close to WS2 nanosheets, resulting in upconversion fluorescence energy transfer from UCNPs to WS2 nanosheets, and the UCNP fluorescence was quenched. With the introduction of CEA into the UCNPs-aptamer complex system, the aptamer preferentially bound to CEA resulting in a change in spatial conformation which caused UCNPs to depart from WS2 nanosheets. As a result, the energy transfer was inhibited and the fluorescence of UCNPs was observed again, and the degree of fluorescence recovery was linearly related to the concentration of CEA in a range of 0.05-10 ng mL-1 with a limit of detection of 0.008 ng mL-1. Furthermore, the aptasensor based on UCNPs and WS2 nanosheets could be competent for detecting CEA in human serum, which suggests the great application potential of the proposed aptasensor in clinical diagnosis.

Noncovalent Interaction of Lactoferrin with Epicatechin and Epigallocatechin: Focus on Fluorescence Quenching and Antioxidant Properties.

Lactoferrin (LF) from bovine milk possesses antioxidant activity, immune regulatory and other biological activities. However, the effects of epicatechin (EC) and epigallocatechin (EGC) interacting with LF on the antioxidant activity of LF have not been investigated. Therefore, this study aimed to explore their interaction mechanism and the antioxidant activity of LF. UV spectra revealed that EGC (100 µM) induced a higher blue shift of LF at the maximum absorption wavelength than that of EC (100 µM). Fluorescence spectra results suggested that LF fluorescence was quenched by EC and EGC in the static type, which changed the polarity of the microenvironment around LF. The quenching constants Ksv (5.91 × 103-9.20 × 103) of EC-LF complexes at different temperatures were all higher than that (1.35 × 103-1.75 × 103) of the EGC-LF complex. EC could bind to LF via hydrophobic interactions while hydrogen bonding and van der Waals forces drove the binding of EGC to LF. Both the EC-LF complex and EGC-LF complex could bind to LF with one site. EGC formed more hydrogen bonds with LF than that of EC. The antioxidant activity of LF was increased by the high addition level of EC and EGC. These findings would provide more references for developing LF-catechin complexes as functional antioxidants.

Affinity-Based Analysis Methods for the Detection of Aminoglycoside Antibiotic Residues in Animal-Derived Foods: A Review.

With the increasingly serious problem of aminoglycoside antibiotic residues, it is imperative to develop rapid, sensitive and efficient detection methods. This article reviews the detection methods of aminoglycoside antibiotics in animal-derived foods, including enzyme-linked immunosorbent assay, fluorescent immunoassay, chemical immunoassay, affinity sensing assay, lateral flow immunochromatography and molecular imprinted immunoassay. After evaluating the performance of these methods, the advantages and disadvantages were analyzed and compared. Furthermore, development prospects and research trends were proposed and summarized. This review can serve as a basis for further research and provide helpful references and new insights for the analysis of aminoglycoside residues. Accordingly, the in-depth investigation and analysis will certainly make great contributions to food safety, public hygiene and human health.

A microbial quantity monitoring model based on 3D fluorescence data of the cucumber storeroom gas and its use in providing auxiliary early spoilage warning.

A real-time model for monitoring the microbial quantity based on the microbial intrinsic fluorescence information of cucumber storeroom gas was established. Firstly, 3D fluorescence data of the storeroom gas were collected on different storage days. Secondly, the number of components of a parallel factor model was determined to be 3 using the core consistency diagnostic. Thirdly, parallel factor analysis was used to decompose the fluorescence data to obtain the excitation spectra, emission spectra and concentration scores of 3 components. The positions of the fluorescence peaks were consistent with the fingerprints of tryptophan-like, tyrosine-like and phenylalanine-like substances in the characteristic spectrum of each component. And then the prediction model was constructed by fitting the concentration scores of the 3 components with the microbial quantity, and the coefficient of determination was 98.27%, and the cross-validation determination coefficient could reach 91.97%. Finally, after integrating the predicted value of the microbial quantity and the total chromatism of the cucumber pericarp during cucumber storage, the spoilage date was determined to be the 7th day by K-means clustering. The results show that the monitoring model constructed through distinguishing the fluorescence data of airborne microorganisms can effectively monitor the spoilage process.

A metabolomics study of Qianliexin capsule treatment of benign prostatic hyperplasia induced by testosterone propionate in the rat model.

A metabolomics investigation of the treatment effect of Qianliexin (QLX) capsules was conducted on rats with benign prostatic hyperplasia (BPH) induced by testosterone propionate. Establishment of the BPH model was confirmed using the prostatic index. Hematoxylin and eosin (HE) staining for TGF-ß, EGFR, collagen, IL-1 ß, TNF-α was performed and changes in urine volume were measured. Urine and serum samples were collected from three groups, including a control group, a BPH model group and a QLX-treated group and subjected to metabolomics profiling based on ultrahigh-performance liquid chromatography-mass spectrometry. Pharmacodynamics analysis showed that the QLX group had significantly lower histopathological damage, fibrosis damage, and inflammation and higher urine output compared with the model group. Twenty-two potential biomarkers were identified in urine samples and 23 metabolites were identified in plasma samples. Alterations in metabolic patterns were evident in all sample types. The treatment effects of QLX appear to involve various metabolic pathways including lipid metabolism, fatty acid metabolism and purine generation and significantly reduced the pathological symptoms and related biochemical indicators of BPH and improved the level of potential marker metabolites. This comprehensive study suggested that differential markers provided insights into the metabolic pathways involved in BPH and the treatment effects of QLX.

Integrative metabolic profile of myelodysplastic syndrome based on UHPLC-MS.

Myelodysplastic syndrome (MDS) is a neoplastic disease originating from hematopoietic stem cells. Currently, hematopoietic stem cell transplantation (HSCT) is the most effective cure, although lenalidomide, azacytidine, and decitabine have been applied to relieve symptoms of MDS. The purpose of this study was to evaluate the changes in endogenous metabolites by applying a UHPLC-MS (ultra-high-performance liquid chromatography-MS) metabolomics approach and to investigate metabolic pathways related to MDS. An untargeted metabolomics approach based on UHPLC-MS in combination with multivariate data analysis, including partial least squares discrimination analysis and orthogonal partial least squares discriminant analysis, was established to investigate potential biomarkers in the plasma of MDS patients. As a result, 29 biomarkers were identified to distinguish between MDS patients, HSCT patients, and healthy controls, which were mainly related to inflammation regulation, amino acid metabolism, fatty acid metabolism, and energy metabolism. To our knowledge, this is the first time where plasma metabolomics was combined with HSCT to study the pathogenesis and therapeutic target of MDS. The identification of biomarkers and analysis of metabolic pathways could offer the possibility of discovering new therapeutic targets for MDS in the future.

Investigation of pathogenesis and therapeutic targets of acute myeloid leukemia based on untargeted plasma metabolomics and network pharmacology approach.

Acute myeloid leukemia (AML) is a malignant disease originating from bone marrow hematopoietic stem cells, characterized by anemia, hemorrhage, fever, and infection, with low survival rate. However, the pathogenesis of AML is not fully understood at present. In this work, an integrated approach based untargeted metabolomics and network pharmacology was adopted to elucidate the pathogenesis of AML. Metabolic profiling of plasma samples from 14 patients and 16 healthy individuals were performed based on UHPLC-MS platform. As a result, 23 metabolites were identified by using the human metabolite database based on PLS-DA (partial least squares discriminant analysis) and independent sample test. And metabolic pathways related to AML mainly included fatty acid metabolism, amino acid metabolism, energy metabolism and lipid metabolism. Meanwhile, biomarkers-targets-pathways-disease network was constructed, 75 biomarker targets and 122 disease targets were identified. Furthermore, 30 pathways were predicted, some of which were consistent with these in metabolomics. This is the first time that metabolomics and network pharmacology approach have been combined to investigate the pathogenesis and therapeutic targets of AML. ALDH, CYP2E1 and CYP3A4 were potential therapeutic targets for AML, which provide available way to elucidate the pathogenesis and treatment of AML.

Ultra-trace Extraction of Two Bactericides Via Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction.

BACKGROUND: A simple, rapid and sensitive method coupling ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) with ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of malachite green (MG) and crystal violet (CV) in different water samples. OBJECTIVE: In ultrasound-assisted DLLME procedure, several parameters affecting the extraction efficiency, including pH, type and volume of the extraction and dispersive solvents, extraction time, ionic strength, were optimized to improve the accuracy and precision of this method. METHODS: MG and CV were extracted and preconcentrated using dichloromethane and acetonitrile as the extraction and dispersive solvents, respectively. RESULTS: Under the optimum conditions, the proposed method affords good linearity in the range of 0.40-20.0 ng/L, and the limit of detections were 0.21 and 0.32 ng/L for MG and CV, respectively. The recoveries of the method at three spiked levels were in the range of 83.4-94.2% with relative standard deviations lower than 4.7% (n = 3). CONCLUSIONS: Satisfactorily, no significant matrix effect has been found as the data ranged between 68% and 102%.

A highly sensitive aptasensor for vascular endothelial growth factor based on fluorescence resonance energy transfer from upconversion nanoparticles to MoS2 nanosheets.

A novel sensitive aptasensor for vascular endothelial growth factor-165 (VEGF165) was constructed based on fluorescence resonance energy transfer (FRET) by employing upconversion nanoparticles (UCNPs) and MoS2 nanosheets as the energy donor and acceptor, respectively. The upconversion fluorescence resonance energy transfer (UC-FRET) was triggered by the physical adsorption interaction between the aptamer and MoS2 nanosheets, leading to a remarkable quenching of UCNP fluorescence up to 95%. Upon addition of VEGF165 to the UCNP-aptamer system before MoS2 nanosheets were added, the aptamer preferentially bound to VEGF165 with the change of spatial conformation, which weakened the van der Waals' force between the MoS2 nanosheets and the aptamer, thus leading to the separation of the donor and the acceptor. Consequently, the FRET phenomenon was inhibited and the luminescence of UCNPs was regained, which was linearly related to the concentration of VEGF165 in the range of 0.1 ng mL-1 to 16 ng mL-1. By taking advantage of the extreme fluorescence quenching ability of MoS2 nanosheets and the optical merits of UCNPs, the aptasensor based on UC-FRET exhibited favorable performance for the homogeneous assay of VEGF165 in human serum, which is of great value for clinical diagnosis of tumors and related biological studies.

Magnetic dummy-template molecularly imprinted polymers based on multi-walled carbon nanotubes for simultaneous selective extraction and analysis of phenoxy carboxylic acid herbicides in cereals.

A novel of magnetic dummy-template molecularly imprinted polymers (mag-MWCNTs-DMIPs) were prepared by surface molecular imprinting technique. The structure of polymers were characterized and the binding properties were assessed by adsorption experiments. The synthetic mag-MWCNTs-DMIPs exhibit satisfying adsorption capacity, excellent selectivity and fast adsorption rate toward phenoxy carboxylic acid (PCA) herbicides. Afterwards, a reliable analytical method for selective separation and determination of trace PCA herbicides in cereals was established by using magnetic solid-phase extraction (mag-MWCNTs-DMIPs as magnetic adsorbent) and UPLC-MS/MS detection. A series of requisite factors were optimized in detail to achieve expected extraction performance. Under the optimum MSPE parameters, the mean spiked recoveries for analytes in different cereals ranged from 86.7% to 95.2% with intra- and inter-day precision not greater than 8.5% and 10.6%, respectively. At last, the developed method was successfully utilized for determination the four PCA herbicides in actual cereals.

Transcriptomic analysis reveals hub genes and subnetworks related to ROS metabolism in Hylocereus undatus through novel superoxide scavenger trypsin treatment during storage.

BACKGROUND: It was demonstrated in our previous research that trypsin scavenges superoxide anions. In this study, the mechanisms of storage quality improvement by trypsin were evaluated in H. undatus. RESULTS: Trypsin significantly delayed the weight loss and decreased the levels of ROS and membrane lipid peroxidation. Transcriptome profiles of H. undatus treated with trypsin revealed the pathways and regulatory mechanisms of ROS genes that were up- or downregulated following trypsin treatment by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses. The current results showed that through the regulation of the expression of hub redox enzymes, especially thioredoxin-related proteins, trypsin can maintain low levels of endogenous active oxygen species, reduce malondialdehyde content and delay fruit aging. In addition, the results of protein-protein interaction networks suggested that the downregulated NAD(P) H and lignin pathways might be the key regulatory mechanisms governed by trypsin. CONCLUSIONS: Trypsin significantly prolonged the storage life of H. undatus through regulatory on the endogenous ROS metabolism. As a new biopreservative, trypsin is highly efficient, safe and economical. Therefore, trypsin possesses technical feasibility for the quality control of fruit storage.

The fabrication of a thiol-modified chitosan magnetic graphene oxide nanocomposite and its adsorption performance towards the illegal drug clenbuterol in pork samples.

A novel thiol (provided by (3-mercaptopropyl) trimethoxysilane, MPTS)-modified chitosan magnetic graphene oxide nanocomposite (Fe3O4@SiO2/GO/CS/MPTS) was synthesized and characterized for the first time as an efficient magnetic sorbent for the enrichment and extraction of trace levels of clenbuterol in pork samples (muscle, fat, heart and liver). Various greatly influential parameters were optimized using a Box-Behnken design (BBD) through the response surface methodology (RSM) to obtain more satisfactory recovery. Under optimum conditions, the method detection limits (MDLs) were in the range of 0.054-0.136 ng g-1. The recoveries of three spiked levels ranged from 84.7% to 101.1%, and the relative standard deviations (RSDs) were lower than 9.3%. The results of the adsorption experiments showed that the maximum adsorption capacity of Fe3O4@SiO2/GO/CS/MPTS for clenbuterol was 214.13 mg g-1. The adsorption process was most consistent with pseudo second-order kinetics and Langmuir adsorption isotherm, indicating a homogeneous process with a chemisorptive nature. Also, the nanocomposite exhibited high adsorption capability for clenbuterol compared with Fe3O4@SiO2/GO and Fe3O4@SiO2/GO/CS. In addition, regeneration of the nanocomposite was effectively achieved, and it retained about 82% of its initial capacity after four cycles. All these results indicate that the synthetic nanocomposite is a promising efficient adsorbent for the adsorption of clenbuterol with high adsorption capacity and low cost.

Establishing water-soluble layered WS2 nanosheet as a platform for biosensing.

Layered WS2 nanosheet is a kind of two-dimensional (2D) covalent-network solid material with remarkable structural and electronic properties that has attracted increasing interest in recent years. In this work, we propose a one-step sonication-assisted exfoliation method to prepare water-soluble WS2 nanosheet and demonstrate its application as a biosensing platform. The synthesis route is simple and straightforward. We reveal that single-strand DNA (ssDNA) chains can readily be adsorbed on the nanosheet, leading to complete and fast quenching of a fluorescent dye tagged to the DNA chain. The adsorbed ssDNA is detachable from the nanosheet upon the interaction with other biomolecules, resulting in the restoration of the fluorescence. The 2D WS2 nanosheet thus acts as an efficient platform for assembling of bioprobes. Because of the extraordinarily high quenching efficiency, which is the synergic result of both excited-state energy transfer and static quenching, the WS2 platform affords minimal background and high sensitivity. Our attempt will extend the application of this material to biosensing and probing areas.

An MnO2 nanosheet as a label-free nanoplatform for homogeneous biosensing.

An ultrathin MnO2 nanosheet is established as a label-free two-dimensional nanoplatform for homogeneous biosensing. Two biosensors based on an MnO2 nanosheet with favourable performances are constructed for OTA and Cat D using different probes and following different sensing principles.

Graphitic carbon-nanoparticle-based single-label nanobeacons.

Shining a nanobeacon: Single-label nanobeacon sensors were constructed by using graphitic carbon nanoparticles (CNPs) and their oxides as energy acceptors (see figure; FRET=fluorescence resonance energy transfer). Excellent sensing performances were achieved with simplified operation and lowered cost.

An effective approach to enhanced energy-transfer efficiency from up-converting phosphors and increased assay sensitivity.

The energy transfer efficiency from up-converting donors was significantly enhanced by constructing beacon sensors, which led to increased sensitivities in DNA recognition and protein determination.

Design, synthesis and docking studies on benzamide derivatives as histone deacetylase inhibitors.

A series of benzamide derivatives including two scaffolds were designed and synthesized as potential histone deacetylase inhibitors. Most of synthesized compounds showed moderate enzymatic potency at the same order of magnitude, and compound 12b possessed better potency to the positive control (3.8 µM vs 13.0 µM). It also showed a 50-fold increase in vitro anticancer activity against DU-145 cell-lines. Molecular docking studies were carried out and used to explain the structure-activity relationships observed in vitro. Then we found that the cavity surrounded by ASP104, HIS33, PRO34 and PHE155 may be crucial for the inhibitors' activity. The docking results provide some useful information for future design of more potent inhibitors.