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  • MDPI AG  (8)
  • 1
    In: Marine Drugs, MDPI AG, Vol. 18, No. 5 ( 2020-05-22), p. 276-
    Abstract: A new pentaketide derivative, penilactonol A (1), and two new hydroxyphenylacetic acid derivatives, (2’R)-stachyline B (2) and (2’R)-westerdijkin A (3), together with five known metabolites, bisabolane-type sesquiterpenoids 4–6 and meroterpenoids 7 and 8, were isolated from the solid culture of a marine alga-associated fungus Penicillium chrysogenum LD-201810. Their structures were elucidated based on extensive spectroscopic analyses, including 1D/2D NMR and high resolution electrospray ionization mass spectra (HRESIMS). The absolute configurations of the stereogenic carbons in 1 were determined by the (Mo2(OAc)4)-induced circular dichroism (CD) and comparison of the calculated and experimental electronic circular dichroism (ECD) spectra, while the absolute configuration of the stereogenic carbon in 2 was established using single-crystal X-ray diffraction analysis. Compounds 2 and 3 adapt the 2’R-configuration as compared to known hydroxyphenylacetic acid-derived and O-prenylated natural products. The cytotoxicity of 1–8 against human carcinoma cell lines (A549, BT-549, HeLa, HepG2, MCF-7, and THP-1) was evaluated. Compound 3 exhibited cytotoxicity to the HepG2 cell line with an IC50 value of 22.0 μM. Furthermore, 5 showed considerable activities against A549 and THP-1 cell lines with IC50 values of 21.2 and 18.2 μM, respectively.
    Type of Medium: Online Resource
    ISSN: 1660-3397
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2175190-0
    SSG: 15,3
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  • 2
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  International Journal of Molecular Sciences Vol. 23, No. 20 ( 2022-10-20), p. 12608-
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 20 ( 2022-10-20), p. 12608-
    Abstract: Cardiovascular diseases are associated with platelet hyperactivity, and downregulating platelet activation is one of the promising antithrombotic strategies. This study newly extracted two polysaccharides (purified exopolysaccharides, EPSp and purified intercellular exopolysaccharides, IPSp) from Cordyceps sinensis Cs-4 mycelial fermentation powder, and investigated the effects of the two polysaccharides and their gut bacterial metabolites on platelet functions and thrombus formation. EPSp and IPSp are majorly composed of galactose, mannose, glucose, and arabinose. Both EPSp and IPSp mainly contain 4-Galp and 4-Glcp glycosidic linkages. EPSp and IPSp significantly inhibited human platelet activation and aggregation with a dose-dependent manner, and attenuated thrombus formation in mice without increasing bleeding risk. Furthermore, the EPSp and IPSp after fecal fermentation showed enhanced platelet inhibitory effects. The results have demonstrated the potential value of Cs-4 polysaccharides as novel protective ingredients for cardiovascular diseases.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 3
    In: Land, MDPI AG, Vol. 11, No. 12 ( 2022-11-22), p. 2104-
    Abstract: Habitat fragmentation is considered a major threat to biodiversity worldwide. Two endangered species, the blood pheasant (Ithaginis cruentus) and the blue eared pheasant (Crossoptilon auritum), co-exist in a fragmented forest in the Qilian Mountains. However, how their habitats react to the fragmenting landscape remains unclear. Therefore, we carried out a field survey in the core habitat of the two species in Qilian Mountains National Park and used the MaxEnt Model to predict their potential distribution and to assess the protection efficiency. Then, we utilized a modified within-patch fragmentation categorizing model to identify how their functional fragmentations differentiated. The results showed that the habitat utilization of the two pheasant species was significantly different, with a potential distribution area of 18,281 km2 for the blood pheasant and 43,223 km2 for the blue eared pheasant. The habitat of the blue eared pheasant is highly fragmented with 27.7% categorized as ‘Interior’ and 49.3% as ‘Edge’, while the habitat of the blood pheasant is more severe with 2.1% categorized as ‘Interior’ and 50.4% as ‘Edge’. Analysis shows that large areas of habitat for the two pheasants remain unprotected by the Qilian Mountains National Park. The intense grazing and human infrastructure may have a large effect on the currently highly fragmented landscape. Future measurements are needed to alleviate this conflict.
    Type of Medium: Online Resource
    ISSN: 2073-445X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2682955-1
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  • 4
    In: Polymers, MDPI AG, Vol. 16, No. 7 ( 2024-03-25), p. 902-
    Abstract: A family of titanium complexes (Ti1–Ti7) with the general formula LTiCl3, supported by tridentate phenoxyimine [O−NO] ligands (L1–L7) bearing bulky sidearms, were synthesized by treating the corresponding ligands with stoichiometric amount of TiCl4. All the ligands and complexes were well characterized by 1H and 13C NMR spectroscopies, in which ortho- methoxyl groups on N-aryl moieties shifted to downfield, corroborating the successful coordination reaction. Structural optimization by DFT calculations revealed that one of the phenyl groups on dibenzhydryl moiety could form π-π stacking interaction with the salicylaldimine plane, because of which the obtained titanium complexes revealed good thermal stabilities for high-temperature polymerization of ethylene. The thermal robustness of the complexes was closely related to the strength of π-π stacking interactions, which were mainly influenced by the substituents on the dibenzhydryl moieties; Ti1, Ti4 and Ti5 emerged as the three best-performing complexes at 110 °C. With the aid of such π-π stacking interactions, the complexes were also found to be active at 〉 150 °C, although decreased activities were witnessed. Besides homopolymerizations, complexes Ti1–Ti7 were also found to be active for the high-temperature copolymerization of ethylene and 1-octene, but with medium incorporation percentage, demonstrating their medium copolymerization capabilities.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    Language: English
    Publisher: MDPI AG
    Publication Date: 2024
    detail.hit.zdb_id: 2527146-5
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  • 5
    In: Healthcare, MDPI AG, Vol. 10, No. 1 ( 2022-01-17), p. 175-
    Abstract: (1) Background: Chest radiographs are the mainstay of initial radiological investigation in this COVID-19 pandemic. A reliable and readily deployable artificial intelligence (AI) algorithm that detects pneumonia in COVID-19 suspects can be useful for screening or triage in a hospital setting. This study has a few objectives: first, to develop a model that accurately detects pneumonia in COVID-19 suspects; second, to assess its performance in a real-world clinical setting; and third, by integrating the model with the daily clinical workflow, to measure its impact on report turn-around time. (2) Methods: The model was developed from the NIH Chest-14 open-source dataset and fine-tuned using an internal dataset comprising more than 4000 CXRs acquired in our institution. Input from two senior radiologists provided the reference standard. The model was integrated into daily clinical workflow, prioritising abnormal CXRs for expedited reporting. Area under the receiver operating characteristic curve (AUC), F1 score, sensitivity, and specificity were calculated to characterise diagnostic performance. The average time taken by radiologists in reporting the CXRs was compared against the mean baseline time taken prior to implementation of the AI model. (3) Results: 9431 unique CXRs were included in the datasets, of which 1232 were ground truth-labelled positive for pneumonia. On the “live” dataset, the model achieved an AUC of 0.95 (95% confidence interval (CI): 0.92, 0.96) corresponding to a specificity of 97% (95% CI: 0.97, 0.98) and sensitivity of 79% (95% CI: 0.72, 0.84). No statistically significant degradation of diagnostic performance was encountered during clinical deployment, and report turn-around time was reduced by 22%. (4) Conclusion: In real-world clinical deployment, our model expedites reporting of pneumonia in COVID-19 suspects while preserving diagnostic performance without significant model drift.
    Type of Medium: Online Resource
    ISSN: 2227-9032
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2721009-1
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  • 6
    In: Molecules, MDPI AG, Vol. 20, No. 3 ( 2015-03-06), p. 4337-4356
    Abstract: Paclitaxel (PTX, taxol), a classical antitumor drug against a wide range of tumors, shows poor oral bioavailability. In order to improve the oral bioavailability of PTX, glycyrrhizic acid (GA) was used as the carrier in this study. This was the first report on the preparation, characterization and the pharmacokinetic study in rats of PTX-loaded GA micelles The PTX-loaded micelles, prepared with ultrasonic dispersion method, displayed small particle sizes and spherical shapes. Differential scanning calorimeter (DSC) thermograms indicated that PTX was entrapped in the GA micelles and existed as an amorphous state. The encapsulation efficiency was about 90%, and the drug loading rate could reach up to 7.90%. PTX-loaded GA micelles displayed a delayed drug release compared to Taxol in the in vitro release experiment. In pharmacokinetic study via oral administration, the area under the plasma concentration-time curve (AUC0→24 h) of PTX-loaded GA micelles was about six times higher than that of Taxol (p 〈 0.05). The significant oral absorption enhancement of PTX from PTX-loaded GA micelles could be largely due to the increased absorption in jejunum and colon intestine. All these results suggested that GA would be a promising carrier for the oral delivery of PTX.
    Type of Medium: Online Resource
    ISSN: 1420-3049
    Language: English
    Publisher: MDPI AG
    Publication Date: 2015
    detail.hit.zdb_id: 2008644-1
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  • 7
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Metals Vol. 12, No. 8 ( 2022-07-22), p. 1236-
    In: Metals, MDPI AG, Vol. 12, No. 8 ( 2022-07-22), p. 1236-
    Abstract: A new D457 × 7.1 X65ERW oil pipeline leaked twice during the pressure test. The two failed oil pipes belonged to the same batch of products from the same manufacturer. Failure analysis showed that the cracks in the 1# and 2# cracking pipes propagated from the outer surface of the pipe wall to the inner surface along the weld fusion line. The inclusion phase distributed in chains in the weld zone is speculated to be the root cause of the cracking in the pressure test. The fitness-for-service of this batch of steel pipes was analyzed using the failure-assessment chart technique. The batch of steel pipes could be used safely under the design pressure of 10 MPa, and the re-evaluation period of three years was recommended for the pipeline based on the fatigue results of the steel-pipe weld zone.
    Type of Medium: Online Resource
    ISSN: 2075-4701
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662252-X
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  • 8
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  Micromachines Vol. 12, No. 5 ( 2021-05-17), p. 567-
    In: Micromachines, MDPI AG, Vol. 12, No. 5 ( 2021-05-17), p. 567-
    Abstract: Reciprocating motion is a widely existing form of mechanical motion in the natural environment. Triboelectric nanogenerators (TENGs) that work in sliding mode are ideal for harnessing large-distance reciprocating motion, and their energy conversion efficiency could be greatly enhanced by adding springs to them. Herein, we focused on investigating the design and optimization principles of sliding mode TENGs by analyzing the effects of spring parameters and vibration frequency on the triboelectric output performance of typical cylindrical sliding TENGs (CS-TENGs). Experimental study and finite elemental analysis were carried out based on a CS-TENG model assembled using a polytetrafluoroethylene (PTFE) film as the negative layer and an aluminum film as the positive layer. The energy output was found to be mainly affected by the change of relative displacement between the two friction layers, rather than the reactive force applied by the springs or the velocity of the sliding motion. However, the frequency of the output signals could be improved when the stiffness coefficient of the springs and the CS-TENG vibration frequency were increased. This study provides valuable directions for the design and optimization of sliding mode TENGs containing springs, and will motivate in-depth research on the fundamental principles of TENG operation.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2620864-7
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