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  • 1
    Online Resource
    Online Resource
    Novel Chitosan Derivatives and Their Multifaceted Biological Applications
    MDPI AG ; 2022
    In:  Applied Sciences Vol. 12, No. 7 ( 2022-03-23), p. 3267-
    Details
    In: Applied Sciences, MDPI AG, Vol. 12, No. 7 ( 2022-03-23), p. 3267-
    Abstract: Chitosan is a rather attractive material, especially because of its bio-origins as well as generation from exoskeletal waste. As the mantle has been effectively transferred from chitin to chitosan, so has it been extrapolated to in-house synthesized novel chitosan derivatives. This review comprehensively lists the available novel chitosan derivatives (ChDs) and summarizes their biological applications. The fact that chitosan derivatives do comprise multifaceted biological applications is attested by the voluminous reports on their varied contributions. However, this review points out to the fact that there has been selective focus on bio functions such as antifungal, antioxidant, antibacterial, whereas other biomedical applications and antiviral applications remain relatively less explored. With their current functionality record, there is definitely no doubt that the plethora of synthesized ChDs will have a profound impact on the unexplored biological aspects. This review points out this lacuna as room for future exploration.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app12073267
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704225-X
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  • 2
    Online Resource
    Online Resource
    Melatonin Modulates Neuronal Cell Death Induced by Endoplasmic Reticulum Stress under Insulin Resistance Condition
    MDPI AG ; 2017
    In:  Nutrients Vol. 9, No. 6 ( 2017-06-10), p. 593-
    Details
    In: Nutrients, MDPI AG, Vol. 9, No. 6 ( 2017-06-10), p. 593-
    Type of Medium: Online Resource
    ISSN: 2072-6643
    URL: Article
    DOI: 10.3390/nu9060593
    Language: English
    Publisher: MDPI AG
    Publication Date: 2017
    detail.hit.zdb_id: 2518386-2
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  • 3
    Online Resource
    Online Resource
    Circulating GLP-1 Levels as a Potential Indicator of Metabolic Syndrome Risk in Adult Women
    MDPI AG ; 2021
    In:  Nutrients Vol. 13, No. 3 ( 2021-03-06), p. 865-
    Details
    In: Nutrients, MDPI AG, Vol. 13, No. 3 ( 2021-03-06), p. 865-
    Abstract: Glucagon-like peptide-1 (GLP-1), an incretin hormone, plays an important role in regulating glucose homeostasis. In this study, the applicability of circulating GLP-1 levels as an early indicator of metabolic syndrome (MetS) risk was examined. Women without diagnosed diseases were grouped according to their number of MetS risk factors (MetS RFs) (no RFs as Super-healthy, n = 61; one or two RFs as MetS risk carriers, n = 60; 3 ≤ RFs as MetS, n = 19). The circulating GLP-1 levels and homeostasis model assessment insulin resistance (HOMA-IR) scores were significantly higher in the MetS group than in the other two groups. The GLP-1 levels correlated positively with adiposity, HOMA-IR, blood pressure, and high sensitivity C-reactive protein (hs-CRP), but not with fasting glucose and lipid profiles, whose significances were maintained after adjustments for age, smoking and drinking habits, menopausal status, and total calorie intake. The GLP-1 levels also increased proportionally with the number of MetS RFs. In the MetS group, the GLP-1 levels were much higher in individuals with obesity (body mass index ≥ 25 kg/m2). In conclusion, the circulating GLP-1 level may be applicable as a potential early indicator of MetS risk in women without diagnosed diseases. Further study with a large population is needed to confirm the conclusion.
    Type of Medium: Online Resource
    ISSN: 2072-6643
    URL: Article
    DOI: 10.3390/nu13030865
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2518386-2
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  • 4
    Online Resource
    Online Resource
    Surveying the Oral Drug Delivery Avenues of Novel Chitosan Derivatives
    MDPI AG ; 2022
    In:  Polymers Vol. 14, No. 11 ( 2022-05-24), p. 2131-
    Details
    In: Polymers, MDPI AG, Vol. 14, No. 11 ( 2022-05-24), p. 2131-
    Abstract: Chitosan has come a long way in biomedical applications: drug delivery is one of its core areas of imminent application. Chitosan derivatives are the new generation variants of chitosan. These modified chitosans have overcome limitations and progressed in the area of drug delivery. This review briefly surveys the current chitosan derivatives available for biomedical applications. The biomedical applications of chitosan derivatives are revisited and their key inputs for oral drug delivery have been discussed. The limited use of the vast chitosan resources for oral drug delivery applications, speculated to be probably due to the interdisciplinary nature of this research, is pointed out in the discussion. Chitosan-derivative synthesis and practical implementation for oral drug delivery require distinct expertise from chemists and pharmacists. The lack of enthusiasm could be related to the inadequacy in the smooth transfer of the synthesized derivatives to the actual implementers. With thiolated chitosan derivatives predominating the oral delivery of drugs, the need for representation from the vast array of ready-to-use chitosan derivatives is emphasized. There is plenty to explore in this direction.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    URL: Article
    DOI: 10.3390/polym14112131
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2527146-5
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  • 5
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    Online Resource
    Evaluating the Anticarcinogenic Activity of Surface Modified/Functionalized Nanochitosan: The Emerging Trends and Endeavors
    MDPI AG ; 2021
    In:  Polymers Vol. 13, No. 18 ( 2021-09-17), p. 3138-
    Details
    In: Polymers, MDPI AG, Vol. 13, No. 18 ( 2021-09-17), p. 3138-
    Abstract: Chitosan begins its humble journey from marine food shell wastes and ends up as a versatile nutraceutical. This review focuses on briefly discussing the antioxidant activity of chitosan and retrospecting the accomplishments of chitosan nanoparticles as an anticarcinogen. The various modified/functionalized/encapsulated chitosan nanoparticles and nanoforms have been listed and their biomedical deliverables presented. The anticancer accomplishments of chitosan and its modified composites have been reviewed and presented. The future of surface modified chitosan and the lacunae in the current research focus have been discussed as future perspective. This review puts forth the urge to expand the scientific curiosity towards attempting a variety of functionalization and surface modifications to chitosan. There are few well known modifications and functionalization that benefit biomedical applications that have been proven for other systems. Being a biodegradable, biocompatible polymer, chitosan-based nanomaterials are an attractive option for medical applications. Therefore, maximizing expansion of its bioactive properties are explored. The need for applying the ideal functionalization that will significantly promote the anticancer contributions of chitosan nanomaterials has also been stressed.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    URL: Article
    DOI: 10.3390/polym13183138
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527146-5
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  • 6
    Online Resource
    Online Resource
    Low Dose Astaxanthin Treatments Trigger the Hormesis of Human Astroglioma Cells by Up-Regulating the Cyclin-Dependent Kinase and Down-Regulated the Tumor Suppressor Protein P53
    MDPI AG ; 2020
    In:  Biomedicines Vol. 8, No. 10 ( 2020-10-19), p. 434-
    Details
    In: Biomedicines, MDPI AG, Vol. 8, No. 10 ( 2020-10-19), p. 434-
    Abstract: Astaxanthin (AXT) is a xanthophyll carotenoid known to have potent anti-cancer effects via upregulation of the intracellular reactive oxygen species (ROS) levels, which triggers apoptosis of cancer cells. While several studies have shown that AXT has potential as an anti-cancer drug, its effects in glioblastoma multiforme cells remain relatively unknown. In this study, we investigated the effects of AXT in the astroglioma cell lines U251-MG, T98G, and CRT-MG. We found that the response to AXT varied between cell lines. Moreover, U251-MG cells showed a specific hormetic response to AXT. At high concentrations (20–40 μM), AXT triggered apoptosis in U251-MG cells, as it has been previously shown in other cancer cell lines. However, low concentrations (4–8 μM) of AXT were found to upregulate the proliferative cell cycle. Furthermore, at low concentrations, AXT did not affect the intracellular ROS levels, while the superoxide dismutase activity increased moderately. Western blot analysis showed that treatment with a low concentration of AXT upregulated cyclin-dependent kinase (Cdk) 2 and p-Cdk2/3 levels and downregulated the expression of tumor protein p53. Thus, our results showed that AXT has a hormetic effect in the astroglioma cell line U251-MG.
    Type of Medium: Online Resource
    ISSN: 2227-9059
    URL: Article
    DOI: 10.3390/biomedicines8100434
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2720867-9
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  • 7
    Online Resource
    Online Resource
    Anticancer Potential of Lipophilic Constituents of Eleven Shellfish Species Commonly Consumed in Korea
    MDPI AG ; 2021
    In:  Antioxidants Vol. 10, No. 10 ( 2021-10-15), p. 1629-
    Details
    In: Antioxidants, MDPI AG, Vol. 10, No. 10 ( 2021-10-15), p. 1629-
    Abstract: The present study was aimed to investigate the composition and contents and the major lipophilic compounds, including the sterols, fatty acids, and tocols of shellfish species. Moreover, to explore the antitumor activity of these lipophilic constituents, their cytotoxicity potentials were determined against five different human cancer cells, including colon carcinoma (HCT116), epithelial melanoma (A2058), glioblastoma multiforme (T98G), lung carcinoma (A549), and adenocarcinoma (HeLa). The results show a significant variation in the contents and composition of lipophilic constituents among the studied species. The highest omega-3 (n-3) polyunsaturated fatty acids (PUFAs) were recorded from arrow squid and pacific oysters, accounting for 53.2% and 53.0% of their total fatty acids, respectively. However, the highest cholesterol content was also recorded in arrow squid (154.4 mg/100 g; 92.6% of total sterols). In contrast, in the Japanese littleneck, Yesso scallop, and common orient clam, cholesterol was just 17.1%, 18.3%, and 18.9% of total sterols, respectively, making them the richest source of non-cholesterol sterols (NCS). Lipids extracted from shellfish species showed ABTS+•- and DPPH•-scavenging activities. In the cytotoxicity analysis, lipids extracted from the Argentine red shrimp showed the highest cytotoxicity against glioblastoma multiforme T98G cells, with an IC50 value of 12.3 µg/mL. The composition and cytotoxicity data reported herein may help explore the nutritional and anticancer potentials of shellfish species.
    Type of Medium: Online Resource
    ISSN: 2076-3921
    URL: Article
    DOI: 10.3390/antiox10101629
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704216-9
    SSG: 15,3
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  • 8
    Online Resource
    Online Resource
    Nanochitosan: Commemorating the Metamorphosis of an ExoSkeletal Waste to a Versatile Nutraceutical
    MDPI AG ; 2021
    In:  Nanomaterials Vol. 11, No. 3 ( 2021-03-23), p. 821-
    Details
    In: Nanomaterials, MDPI AG, Vol. 11, No. 3 ( 2021-03-23), p. 821-
    Abstract: Chitin (poly-N-acetyl-D-glucosamine) is the second (after cellulose) most abundant organic polymer. In its deacetylated form—chitosan—becomes a very interesting material for medical use. The chitosan nano-structures whose preparation is described in this article shows unique biomedical value. The preparation of nanochitosan, as well as the most vital biomedical applications (antitumor, drug delivery and other medical uses), have been discussed in this review. The challenges confronting the progress of nanochitosan from benchtop to bedside clinical settings have been evaluated. The need for inclusion of nano aspects into chitosan research, with improvisation from nanotechnological inputs has been prescribed for breaking down the limitations. Future perspectives of nanochitosan and the challenges facing nanochitosan applications and the areas needing research focus have been highlighted.
    Type of Medium: Online Resource
    ISSN: 2079-4991
    URL: Article
    DOI: 10.3390/nano11030821
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662255-5
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  • 9
    Online Resource
    Online Resource
    The Industrial Linkages and Supply Effects of the U.S. R&D Sector: Comparison with OECD Countries
    MDPI AG ; 2019
    In:  Social Sciences Vol. 8, No. 3 ( 2019-03-11), p. 89-
    Details
    In: Social Sciences, MDPI AG, Vol. 8, No. 3 ( 2019-03-11), p. 89-
    Abstract: The industrial linkages and supply effects of the U.S. Research and Development (R & D) sector are examined using the input-output approach. Although the U.S. has the highest R & D intensity among major OECD countries, the U.S. R & D sector has relatively low backward and forward linkages to other industrial sectors. Moreover, the supply investment effect of the U.S. R & D sector is the least, showing that the sector is not likely to stimulate the production of the other sectors. The supply shortage effect of the U.S. R & D sector is also the least among the countries. The findings in this study imply that improving the linkages and supply effects of the R & D sector may be more important than increasing only the amount of R & D expenditure in the U.S.
    Type of Medium: Online Resource
    ISSN: 2076-0760
    URL: Article
    DOI: 10.3390/socsci8030089
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2663343-7
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  • 10
    Online Resource
    Online Resource
    Analysis of Gyro Bias Depending on the Position of Inertial Measurement Unit in Rotational Inertial Navigation Systems
    MDPI AG ; 2022
    In:  Sensors Vol. 22, No. 21 ( 2022-10-31), p. 8355-
    Details
    In: Sensors, MDPI AG, Vol. 22, No. 21 ( 2022-10-31), p. 8355-
    Abstract: In this paper, a calibration method for gyro bias that changes depending on the position of the IMU (inertial measurement unit) is proposed to improve the navigation performance of RLG-based RINS (ring-laser-gyro-based rotational inertial navigation system). RINS is a navigation device that compensates for the inertial sensor errors by utilizing the rotation of the IMU. In previous studies, the rotation scheme of the IMU is designed assuming that inertial sensor errors are not affected by position of the IMU. However, changes in temperature distribution, direction of gravity, and dithering according to the rotation of the IMU affect the inertial sensor errors, such as gyro bias. These errors could degrade the long-term navigation performance of RLG-based RINS. To deal with this problem, this paper proposed a compensation method of the gyro bias that changes depending on the position of the IMU. First, RINS is reviewed using a dual-axis 16-position rotation scheme and RLG. Next, the attitude error of RLG-based RINS is derived utilizing navigation equations. The effect of the gyro bias change caused by the change in the IMU attitude for the navigation performance of RINS is analyzed based on navigation equations and simulations. Finally, system-level indirect calibrations for the Z–axis up position and Z–axis down position are performed to calculate the gyro bias change caused by the IMU attitude. The accuracy of the proposed calibration method is verified by long-term navigation test. The test results show that the proposed calibration method improves the navigation performance of RINS compared with the conventional calibration method.
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s22218355
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2052857-7
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