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  • MDPI AG  (85)
  • 1
    Online Resource
    Online Resource
    Highly Selective and Sensitive Sensor Based IL and CMC-MWCNTs Nanocomposite for Rutin Determination
    MDPI AG ; 2023
    In:  Chemosensors Vol. 11, No. 3 ( 2023-03-02), p. 171-
    Details
    In: Chemosensors, MDPI AG, Vol. 11, No. 3 ( 2023-03-02), p. 171-
    Abstract: Rutin is a natural antioxidant flavonoid compound with anti-inflammatory, antioxidant, and antiviral effects that is used to prepare drugs with wide application in clinical treatment. Therefore, the quantitative detection of rutin has important practical significance. In this work, a novel electrochemical sensor based on glassy carbon electrodes (GCEs) modified with sodium carboxymethylcellulose (CMC), multi-walled carbon nanotubes (MWCNTs), and 1-butyl-3-methylimid (ionic liquid, IL) was developed for the super-sensitive detection of the flavonoid rutin. The properties of these modified materials were analyzed by transmission electron microscope (TEM), cyclic voltammograms (CVs), and electrochemical-impedance spectroscopy (EIS). CMC was used to disperse MWCNTs to further enhance their hydrophilicity and biocompatibility. The modified MWCNTs improved the sensitivity of rutin detection. The square-wave voltammetry (SWV) technique showed that the linear range of rutin concentration determination was 0.01 μM to 1 µM and 1 µM to 10 µM. The minimum concentration detection of rutin was 0.83 nM and 6.6 nM, respectively. The proposed sensor presented good selectivity for rutin and successfully analyzed rutin content in the pharmaceutical rutin tablets. These results are consistent with those measured by ultra-high-performance liquid chromatography (UHPLC). Therefore, this sensor has latent application value in the analysis of rutin in food and drug tablets and nutraceutical samples.
    Type of Medium: Online Resource
    ISSN: 2227-9040
    URL: Article
    DOI: 10.3390/chemosensors11030171
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704218-2
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  • 2
    Online Resource
    Online Resource
    Glucose Biosensor Based on Glucose Oxidase Immobilized on BSA Cross-Linked Nanocomposite Modified Glassy Carbon Electrode
    MDPI AG ; 2023
    In:  Sensors Vol. 23, No. 6 ( 2023-03-17), p. 3209-
    Details
    In: Sensors, MDPI AG, Vol. 23, No. 6 ( 2023-03-17), p. 3209-
    Abstract: Glucose sensors based blood glucose detection are of great significance for the diagnosis and treatment of diabetes because diabetes has aroused wide concern in the world. In this study, bovine serum albumin (BSA) was used to cross-link glucose oxidase (GOD) on a glassy carbon electrode (GCE) modified by a composite of hydroxy fullerene (HFs) and multi-walled carbon nanotubes (MWCNTs) and protected with a glutaraldehyde (GLA)/Nafion (NF) composite membrane to prepare a novel glucose biosensor. The modified materials were analyzed by UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The prepared MWCNTs-HFs composite has excellent conductivity, the addition of BSA regulates MWCNTs-HFs hydrophobicity and biocompatibility, and better immobilizes GOD on MWCNTs-HFs. MWCNTs-BSA-HFs plays a synergistic role in the electrochemical response to glucose. The biosensor shows high sensitivity (167 μA·mM−1·cm−2), wide calibration range (0.01–3.5 mM), and low detection limit (17 μM). The apparent Michaelis–Menten constant Kmapp is 119 μM. Additionally, the proposed biosensor has good selectivity and excellent storage stability (120 days). The practicability of the biosensor was evaluated in real plasma samples, and the recovery rate was satisfactory.
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s23063209
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2052857-7
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  • 3
    Online Resource
    Online Resource
    Identification of Small-Molecule Bioactive Constituents from the Leaves of Vaccinium bracteatum Confirms It as a Potential Functional Food with Health Benefits
    MDPI AG ; 2023
    In:  Foods Vol. 12, No. 1 ( 2023-01-01), p. 177-
    Details
    In: Foods, MDPI AG, Vol. 12, No. 1 ( 2023-01-01), p. 177-
    Abstract: The health benefits of Vaccinium bracteatum are well recorded in ancient Chinese medical books and were also demonstrated by modern researches. However, the relationship between its beneficial functions and specific chemical constituents has not been fully characterized. This study investigated the bioactive small-molecule constituents in the leaves of V. bracteatum, which afforded 32 compounds including ten new ones (1–9) and ten pairs of enantiomers (9–18). Their structures with absolute configurations were elucidated by spectroscopic methods, especially nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) analyses, with 1–4 bearing a novel revolving-door shaped scaffold. While half-compounds exhibited decent antioxidant activity by scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, all except 19 and 20 exerted significant capturing activity against diammonium 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radicals. In addition, the new iridoids 1, 5, 6, and 7 exerted apparent neuroprotective activity toward PC12 cells, with 1 being comparable to the positive control, and selective compounds also displayed anti-diabetic and anti-inflammatory properties by inhibiting α-glucosidase and NO production, respectively. The current work revealed that the bioactive small-molecule constituents could be closely related to the functional food property of the title species.
    Type of Medium: Online Resource
    ISSN: 2304-8158
    URL: Article
    DOI: 10.3390/foods12010177
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704223-6
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  • 4
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    MWCNTs-CTAB and HFs-Lac Nanocomposite-Modified Glassy Carbon Electrode for Rutin Determination
    MDPI AG ; 2022
    In:  Biosensors Vol. 12, No. 8 ( 2022-08-11), p. 632-
    Details
    In: Biosensors, MDPI AG, Vol. 12, No. 8 ( 2022-08-11), p. 632-
    Abstract: Rutin is a flavonoid glycoside compound, which is mainly transported via the blood circulation system in the human body. The monitoring of the blood concentration of rutin is of great significance in many fields such as pharmacology and pharmacokinetics. In this work, a biosensor based on multi-walled carbon nanotubes (MWCNTs), cetyltrimethylammonium bromide (CTAB), hydroxyl fullerenes (HFs), and laccase (Lac) nanocomposite-modified glassy carbon electrodes was constructed. The modified materials were characterized with a transmission electron microscope (TEM), cyclic voltammograms (CV), and electrochemical impedance spectroscopy (EIS). CTAB is used to disperse MWCNTs and improve hydrophilicity and biocompatibility of MWCNTs, while the use of Lac can enhance the oxidation of catechol structure in rutin, thus significantly improving the sensitivity and selectivity of the modified electrode. Linear sweep voltammetry (LSV) studies showed that the determination linear ranges of rutin were 0.1 µmol L−1 to 2 µmol L−1 and 2 µmol L−1 to 11 µmol L−1, with the determination limits of 30 nmol L−1 and 95.5 nmol L−1, respectively. The proposed biosensor can be used to detect rutin tablets and serum samples with high recovery, which indicates a good accuracy of this method, and the results are consistent with those measured by the traditional ultra-high performance liquid chromatography (UHPLC) method. Hence, this biosensor has potential practical application value in rutin drug quality testing and clinical blood drug concentration monitoring.
    Type of Medium: Online Resource
    ISSN: 2079-6374
    URL: Article
    DOI: 10.3390/bios12080632
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662125-3
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  • 5
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    Online Resource
    Ovule Development and in Planta Transformation of Paphiopedilum Maudiae by Agrobacterium-Mediated Ovary-Injection
    MDPI AG ; 2020
    In:  International Journal of Molecular Sciences Vol. 22, No. 1 ( 2020-12-23), p. 84-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 22, No. 1 ( 2020-12-23), p. 84-
    Abstract: In this paper, the development of the Paphiopedilum Maudiae embryo sac at different developmental stages after pollination was assessed by confocal laser scanning microscopy. The mature seeds of P. Maudiae consisted of an exopleura and a spherical embryo, but without an endosperm, while the inner integument cells were absorbed by the developing embryo. The P. Maudiae embryo sac exhibited an Allium type of development. The time taken for the embryo to develop to a mature sac was 45-50 days after pollination (DAP) and most mature embryo sacs had completed fertilization and formed zygotes by about 50–54 DAP. In planta transformation was achieved by injection of the ovaries by Agrobacterium, resulting in 38 protocorms or seedlings after several rounds of hygromycin selection, corresponding to 2, 7, 5, 1, 3, 4, 9, and 7 plantlets from Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, respectively. Transformation efficiency was highest at 50 DAP (2.54%), followed by 2.48% at 53 DAP and 2.45% at 48 DAP. Four randomly selected hygromycin-resistant plants were GUS-positive after PCR analysis. Semi-quantitative PCR and quantitative real-time PCR analysis revealed the expression of the hpt gene in the leaves of eight hygromycin-resistant seedlings following Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, while hpt expression was not detected in the control. The best time to inject P. Maudiae ovaries in planta with Agrobacterium is 48-53 DAP, which corresponds to the period of fertilization. This protocol represents the first genetic transformation protocol for any Paphiopedilum species and will allow for expanded molecular breeding programs to introduce useful and interesting genes that can expand its ornamental and horticulturally important characteristics.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms22010084
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 6
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    Integrated Approaches to Reveal Genes Crucial for Tannin Degradation in Aureobasidium melanogenum T9
    MDPI AG ; 2019
    In:  Biomolecules Vol. 9, No. 9 ( 2019-09-02), p. 439-
    Details
    In: Biomolecules, MDPI AG, Vol. 9, No. 9 ( 2019-09-02), p. 439-
    Abstract: Tannins biodegradation by a microorganism is one of the most efficient ways to produce bioproducts of high value. However, the mechanism of tannins biodegradation by yeast has been little explored. In this study, Aureobasidium melanogenum T9 isolated from red wine starter showed the ability for tannins degradation and had its highest biomass when the initial tannic acid concentration was 20 g/L. Furthermore, the genes involved in the tannin degradation process were analyzed. Genes tan A, tan B and tan C encoding three different tannases respectively were identified in the A. melanogenum T9. Among these genes, tan A and tan B can be induced by tannin acid simultaneously at both gene transcription and protein expression levels. Our assay result showed that the deletion of tanA and tanB resulted in tannase activity decline with 51.3 ± 4.1 and 64.1 ± 1.9 U/mL, respectively, which is much lower than that of A. melanogenum T9 with 91.3 ± 5.8 U/mL. In addition, another gene coding gallic acid decarboxylase (gad) was knocked out to better clarify its function. Mutant Δgad completely lost gallic acid decarboxylase activity and no pyrogallic acid was seen during the entire cultivation process, confirming that there was a sole gene encoding decarboxylase in the A. melanogenum T9. These results demonstrated that tanA, tanB and gad were crucial for tannin degradation and provided new insights for the mechanism of tannins biodegradation by yeast. This finding showed that A. melanogenum has potential in the production of tannase and metabolites, such as gall acid and pyrogallol.
    Type of Medium: Online Resource
    ISSN: 2218-273X
    URL: Article
    DOI: 10.3390/biom9090439
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2701262-1
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  • 7
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    The Impurity and Decay-Magnetic Polaron Effects in III–V Compound Gaussian Quantum Wells
    MDPI AG ; 2022
    In:  Coatings Vol. 12, No. 8 ( 2022-07-29), p. 1072-
    Details
    In: Coatings, MDPI AG, Vol. 12, No. 8 ( 2022-07-29), p. 1072-
    Abstract: The effects of a decay magnetic field and hydrogen-like impurities on the ground-state binding energy (GSBE) and ground-state energy (GSE) of weak-coupling bound polarons in asymmetrical Gaussian potential (AGP) III–V compound quantum wells (QWs) were studied based on unitary transformation methods and linear combination operators. By numerical calculation, we found that the polarons were affected by the AGP, the decay magnetic field, Coulomb impurities, and the type of crystal, which led to a series of interesting phenomena, such as changes in the ground-state energy and the ground-state binding energy. The results obtained provide good theoretical guidance for optoelectronic devices and quantum information.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings12081072
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662314-6
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  • 8
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    A Vaccine with Multiple Receptor-Binding Domain Subunit Mutations Induces Broad-Spectrum Immune Response against SARS-CoV-2 Variants of Concern
    MDPI AG ; 2022
    In:  Vaccines Vol. 10, No. 10 ( 2022-10-01), p. 1653-
    Details
    In: Vaccines, MDPI AG, Vol. 10, No. 10 ( 2022-10-01), p. 1653-
    Abstract: With the emergence of more variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the immune evasion of these variants from existing vaccines, the development of broad-spectrum vaccines is urgently needed. In this study, we designed a novel SARS-CoV-2 receptor-binding domain (RBD) subunit (RBD5m) by integrating five important mutations from SARS-CoV-2 variants of concern (VOCs). The neutralization activities of antibodies induced by the RBD5m candidate vaccine are more balanced and effective for neutralizing different SARS-CoV-2 VOCs in comparison with those induced by the SARS-CoV-2 prototype strain RBD. Our results suggest that the RBD5m vaccine is a good broad-spectrum vaccine candidate able to prevent disease from several different SARS-CoV-2 VOCs.
    Type of Medium: Online Resource
    ISSN: 2076-393X
    URL: Article
    DOI: 10.3390/vaccines10101653
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2703319-3
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  • 9
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    1H-2,3-Dihydroperimidine Derivatives: A New Class of Potent Protein Tyrosine Phosphatase 1B Inhibitors
    MDPI AG ; 2013
    In:  Molecules Vol. 19, No. 1 ( 2013-12-23), p. 102-121
    Details
    In: Molecules, MDPI AG, Vol. 19, No. 1 ( 2013-12-23), p. 102-121
    Type of Medium: Online Resource
    ISSN: 1420-3049
    URL: Article
    DOI: 10.3390/molecules19010102
    Language: English
    Publisher: MDPI AG
    Publication Date: 2013
    detail.hit.zdb_id: 2008644-1
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  • 10
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    SP-ILC: Concurrent Single-Pixel Imaging, Object Location, and Classification by Deep Learning
    MDPI AG ; 2021
    In:  Photonics Vol. 8, No. 9 ( 2021-09-18), p. 400-
    Details
    In: Photonics, MDPI AG, Vol. 8, No. 9 ( 2021-09-18), p. 400-
    Abstract: We propose a concurrent single-pixel imaging, object location, and classification scheme based on deep learning (SP-ILC). We used multitask learning, developed a new loss function, and created a dataset suitable for this project. The dataset consists of scenes that contain different numbers of possibly overlapping objects of various sizes. The results we obtained show that SP-ILC runs concurrent processes to locate objects in a scene with a high degree of precision in order to produce high quality single-pixel images of the objects, and to accurately classify objects, all with a low sampling rate. SP-ILC has potential for effective use in remote sensing, medical diagnosis and treatment, security, and autonomous vehicle control.
    Type of Medium: Online Resource
    ISSN: 2304-6732
    URL: Article
    DOI: 10.3390/photonics8090400
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2770002-1
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