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  • MDPI AG  (38)
  • 1
    Online Resource
    Online Resource
    Improved Membrane Inlet Mass Spectrometer Method for Measuring Dissolved Methane Concentration and Methane Production Rate in a Large Shallow Lake
    MDPI AG ; 2021
    In:  Water Vol. 13, No. 19 ( 2021-09-29), p. 2699-
    Details
    In: Water, MDPI AG, Vol. 13, No. 19 ( 2021-09-29), p. 2699-
    Abstract: Natural water bodies, such as lakes, rivers, and oceans, are important sources of atmospheric methane (CH4). Therefore, quantitative and accurate determination of the dissolved CH4 concentration in water is of great significance for studying CH4 emissions and providing an in-depth understanding of the carbon cycle. Headspace gas chromatography (HGC) is the traditional method for measuring CH4 in water. Despite its long success, it has a lot of problems in use, such as complex pretreatment and a long measurement time, and it is not suitable for the CH4 determination of a large number of samples. In view of these shortcomings, a more convenient and efficient method based on membrane inlet mass spectrometry (MIMS) for quantitative measurements of the dissolved CH4 concentration in water was established. In our study, the standard curves showed that the method had high accuracy, both at low and high CH4 concentrations. After a laboratory test, to evaluate the sensitivity of this method, samples were collected from a large shallow lake (Lake Taihu). Both the HGC method and MIMS method were used to determine the dissolved CH4 to compare these two methods. The small difference in CH4 concentration obtained from the MIMS and HGC methods and the significant correlation between the CH4 concentrations derived from the MIMS method with those derived from the HGC method showed that the MIMS method could replace the HGC method in the determination of dissolved CH4 in natural waters. In addition, we also measured the sediment CH4 production rates in three different areas of Lake Taihu using a laboratory incubation experiment. During the experiment, significant CH4 accumulations were observed, indicating that sediment CH4 production was an important source of dissolved CH4 in the water column. Our study concluded that the MIMS method was sufficient and a better alternative than the HGC method owing to its capacity to measure a broad range of values plus the fact that it was relatively easy to use with less manipulation of the samples.
    Type of Medium: Online Resource
    ISSN: 2073-4441
    URL: Article
    DOI: 10.3390/w13192699
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2521238-2
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  • 2
    Online Resource
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    Eucommia Polysaccharides Ameliorate Aging-Associated Gut Dysbiosis: A Potential Mechanism for Life Extension in Drosophila
    MDPI AG ; 2023
    In:  International Journal of Molecular Sciences Vol. 24, No. 6 ( 2023-03-20), p. 5881-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 24, No. 6 ( 2023-03-20), p. 5881-
    Abstract: The gut microbiota is increasingly considered to play a key role in human immunity and health. The aging process alters the microbiota composition, which is associated with inflammation, reactive oxygen species (ROS), decreased tissue function, and increased susceptibility to age-related diseases. It has been demonstrated that plant polysaccharides have beneficial effects on the gut microbiota, particularly in reducing pathogenic bacteria abundance and increasing beneficial bacteria populations. However, there is limited evidence of the effect of plant polysaccharides on age-related gut microbiota dysbiosis and ROS accumulation during the aging process. To explore the effect of Eucommiae polysaccharides (EPs) on age-related gut microbiota dysbiosis and ROS accumulation during the aging process of Drosophila, a series of behavioral and life span assays of Drosophila with the same genetic background in standard medium and a medium supplemented with EPs were performed. Next, the gut microbiota composition and protein composition of Drosophila in standard medium and the medium supplemented with EPs were detected using 16S rRNA gene sequencing analysis and quantitative proteomic analysis. Here, we show that supplementation of Eucommiae polysaccharides (EPs) during development leads to the life span extension of Drosophila. Furthermore, EPs decreased age-related ROS accumulation and suppressed Gluconobacter, Providencia, and Enterobacteriaceae in aged Drosophila. Increased Gluconobacter, Providencia, and Enterobacteriaceae in the indigenous microbiota might induce age-related gut dysfunction in Drosophila and shortens their life span. Our study demonstrates that EPs can be used as prebiotic agents to prevent aging-associated gut dysbiosis and reactive oxidative stress.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms24065881
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 3
    Online Resource
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    Oxidative Stress in Hypoxic-Ischemic Encephalopathy: Molecular Mechanisms and Therapeutic Strategies
    MDPI AG ; 2016
    In:  International Journal of Molecular Sciences Vol. 17, No. 12 ( 2016-12-10), p. 2078-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 17, No. 12 ( 2016-12-10), p. 2078-
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms17122078
    Language: English
    Publisher: MDPI AG
    Publication Date: 2016
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 4
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    Epidemiological Characteristics and the Dynamic Transmission Model of Dengue Fever in Zhanjiang City, Guangdong Province in 2018
    MDPI AG ; 2022
    In:  Tropical Medicine and Infectious Disease Vol. 7, No. 9 ( 2022-08-25), p. 209-
    Details
    In: Tropical Medicine and Infectious Disease, MDPI AG, Vol. 7, No. 9 ( 2022-08-25), p. 209-
    Abstract: Background: With the progress of urbanization, the mobility of people has gradually increased, which has led to the further spread of dengue fever. This study evaluated the transmissibility of dengue fever within districts and between different districts in Zhanjiang City to provide corresponding advice for cross-regional prevention and control. Methods: A mathematical model of transmission dynamics was developed to explore the transmissibility of the disease and to compare that between different regions. Results: A total of 467 DF cases (6.38 per 100,000 people) were reported in Zhanjiang City in 2018. In the model, without any intervention, the number of simulated cases in this epidemic reached about 950. The dengue fever transmissions between districts varied within and between regions. When the spread of dengue fever from Chikan Districts to other districts was cut off, the number of cases in other districts dropped significantly or even to zero. When the density of mosquitoes in Xiashan District was controlled, the dengue fever epidemic in Xiashan District was found to be significantly alleviated. Conclusions: When there is a dengue outbreak, timely measures can effectively control it from developing into an epidemic. Different prevention and control measures in different districts could efficiently reduce the risk of disease transmission.
    Type of Medium: Online Resource
    ISSN: 2414-6366
    URL: Article
    DOI: 10.3390/tropicalmed7090209
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2934690-3
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  • 5
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    Prognostic Inflammatory Index Based on Preoperative Peripheral Blood for Predicting the Prognosis of Colorectal Cancer Patients
    MDPI AG ; 2020
    In:  Cancers Vol. 13, No. 1 ( 2020-12-22), p. 3-
    Details
    In: Cancers, MDPI AG, Vol. 13, No. 1 ( 2020-12-22), p. 3-
    Abstract: Host inflammation is a critical component of tumor progression and its status can be indicated by peripheral blood cell counts. We aimed to construct a comprehensively prognostic inflammatory index (PII) based on preoperative peripheral blood cell counts and further evaluate its prognostic value for patients with colorectal cancer (CRC). A total of 9315 patients with stage II and III CRC from training and external validation cohorts were included. The PII was constructed by integrating all the peripheral blood cell counts associated with prognosis in the training cohort. Cox analyses were performed to evaluate the association between PII and overall survival (OS) and disease-free survival (DFS). In the training cohort, multivariate Cox analyses indicated that high OS-PII ( 〉 4.27) was significantly associated with worse OS (HR: 1.330, 95% CI: 1.189–1.489, p 〈 0.001); and high DFS-PII ( 〉 4.47) was significantly associated with worse DFS (HR: 1.366, 95% CI: 1.206–1.548, p 〈 0.001). The prognostic values of both OS-PII and DFS-PII were validated in the external validation cohort. The nomograms achieved good accuracy in predicting both OS and DFS. Time-dependent ROC analyses showed that both OS-PII and DFS-PII have a stable prognostic performance at various follow-up times. The prognostic value of tumor-node-metastasis staging could be enhanced by combining it with either OS-PII or DFS-PII. We demonstrated that PIIs are independent prognostic predictors for CRC patients, and the nomograms based on PIIs can be recommended for personalized survival prediction of patients with CRC.
    Type of Medium: Online Resource
    ISSN: 2072-6694
    URL: Article
    DOI: 10.3390/cancers13010003
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2527080-1
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  • 6
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    Associations of B Vitamin-Related Dietary Pattern during Pregnancy with Birth Outcomes: A Population-Based Study in Northwest China
    MDPI AG ; 2022
    In:  Nutrients Vol. 14, No. 3 ( 2022-01-29), p. 600-
    Details
    In: Nutrients, MDPI AG, Vol. 14, No. 3 ( 2022-01-29), p. 600-
    Abstract: This study aimed to derive a maternal dietary pattern to explain the variation in B vitamins during pregnancy and to investigate this pattern in relation to birth outcomes. A total of 7347 women who gave birth to live newborns less than one year were included. Their dietary pattern during pregnancy was derived using the reduced-rank regression method with six B vitamins as response variables. Associations between dietary pattern score and birth weight, gestational age at delivery, birth weight Z score, low birth weight, preterm, and small-for-gestational-age (SGA) were estimated using generalised linear mixed models. We identified a high B-vitamin dietary pattern characterised by high intakes of animal foods, vegetables, fungi and algae, legumes, and low intakes of oils and cereals. Women in the highest quartile of this pattern score had newborns with a 44.5 g (95% CI: 13.8, 75.2 g) higher birth weight, 0.101 (95% CI: 0.029, 0.172) higher birth weight Z score, and 27.2% (OR: 0.728; 95% CI: 0.582, 0.910) lower risk of SGA than those in the lowest quartile. Our study suggested that adherence to the high B-vitamin dietary pattern during pregnancy was associated with a higher birth weight and a lower risk of SGA.
    Type of Medium: Online Resource
    ISSN: 2072-6643
    URL: Article
    DOI: 10.3390/nu14030600
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2518386-2
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  • 7
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    Fiber Orientation Reconstruction from SEM Images of Fiber-Reinforced Composites
    MDPI AG ; 2023
    In:  Applied Sciences Vol. 13, No. 6 ( 2023-03-14), p. 3700-
    Details
    In: Applied Sciences, MDPI AG, Vol. 13, No. 6 ( 2023-03-14), p. 3700-
    Abstract: The orientation of fibers in composites reinforced with short fibers can provide insight into the microstructure of the material and considerably affect its macroscopic characteristics. However, the present standard techniques for detecting fiber orientation and length based on microscopic image processing have faults in practical applications, including high effort, low efficiency, and unreliable measurement results. In this study, a method for measuring fiber orientation based on 3D reconstructions of scanning electron microscope (SEM) images is provided. The geodesic active contour (GAC) model is applied to segment the fibers in the SEM images. Matching the fiber contours with the scale-invariant feature transformation (SIFT) algorithm successfully extracts 3D orientation information from the fiber contours. The unit vector of the fiber axis is fitted from the extracted point cloud using the ordinary least squares (OLS) method. With a maximum deviation of 3.83° and an average deviation of 1.50°, the measurement findings of this method are substantially comparable to those of the image-measuring instrument. This paper offers a quantitative approach to studying the microstructure of short fiber-reinforced composites, thereby furnishing objective evidence to support the development and research of such materials.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app13063700
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704225-X
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  • 8
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    Robust Control of Electric Tail Reduction System: Uncertainty and Performance Index
    MDPI AG ; 2020
    In:  Applied Sciences Vol. 11, No. 1 ( 2020-12-29), p. 260-
    Details
    In: Applied Sciences, MDPI AG, Vol. 11, No. 1 ( 2020-12-29), p. 260-
    Abstract: The electric tail reduction system of the unmanned helicopter contains uncertainty. To solve this problem, a constraint-following approach was applied to design a novel robust control for uncertain mechanical systems. The dynamic model of the uncertain electric tail reduction system was established by combining the load of the electric tail rotor and the flight state of the helicopter. Based on the Udwadia–Kalaba theory, a robust constraint following the control method was proposed to deal with the uncertainty of the system. In addition, to balance the steady-state performance and control cost of the system, a control parameter optimization design method was proposed to minimize the performance index. Furthermore, the unique solution of the optimal parameter can be obtained. Compared with the LQR control method, the effectiveness of the optimization method of robust constraint following control was verified.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app11010260
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2704225-X
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  • 9
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    Transcriptomic and Functional Analyses of Two Cadmium Hyper-Enriched Duckweed Strains Reveal Putative Cadmium Tolerance Mechanisms
    MDPI AG ; 2023
    In:  International Journal of Molecular Sciences Vol. 24, No. 15 ( 2023-07-29), p. 12157-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 24, No. 15 ( 2023-07-29), p. 12157-
    Abstract: Cadmium (Cd) is one of the most toxic metals in the environment and exerts deleterious effects on plant growth and production. Duckweed has been reported as a promising candidate for Cd phytoremediation. In this study, the growth, Cd enrichment, and antioxidant enzyme activity of duckweed were investigated. We found that both high-Cd-tolerance duckweed (HCD) and low-Cd-tolerance duckweed (LCD) strains exposed to Cd were hyper-enriched with Cd. To further explore the underlying molecular mechanisms, a genome-wide transcriptome analysis was performed. The results showed that the growth rate, chlorophyll content, and antioxidant enzyme activities of duckweed were significantly affected by Cd stress and differed between the two strains. In the genome-wide transcriptome analysis, the RNA-seq library generated 544,347,670 clean reads, and 1608 and 2045 differentially expressed genes were identified between HCD and LCD, respectively. The antioxidant system was significantly expressed during ribosomal biosynthesis in HCD but not in LCD. Fatty acid metabolism and ethanol production were significantly increased in LCD. Alpha-linolenic acid metabolism likely plays an important role in Cd detoxification in duckweed. These findings contribute to the understanding of Cd tolerance mechanisms in hyperaccumulator plants and lay the foundation for future phytoremediation studies.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms241512157
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 10
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    Predicting the Toxicity of Ionic Liquids toward Acetylcholinesterase Enzymes Using Novel QSAR Models
    MDPI AG ; 2019
    In:  International Journal of Molecular Sciences Vol. 20, No. 9 ( 2019-05-02), p. 2186-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 20, No. 9 ( 2019-05-02), p. 2186-
    Abstract: Limited information on the potential toxicity of ionic liquids (ILs) becomes the bottleneck that creates a barrier in their large-scale application. In this work, two quantitative structure-activity relationships (QSAR) models were used to evaluate the toxicity of ILs toward the acetylcholinesterase enzyme using multiple linear regression (MLR) and extreme learning machine (ELM) algorithms. The structures of 57 cations and 21 anions were optimized using quantum chemistry calculations. The electrostatic potential surface area (SEP) and the screening charge density distribution area (Sσ) descriptors were calculated and used for prediction of IL toxicity. Performance and predictive aptitude between MLR and ELM models were analyzed. Highest squared correlation coefficient (R2), and also lowest average absolute relative deviation (AARD%) and root-mean-square error (RMSE) were observed for training set, test set, and total set for the ELM model. These findings validated the superior performance of ELM over the MLR toxicity prediction model.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms20092186
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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