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  • MDPI AG  (94)
  • 1
    In: Forests, MDPI AG, Vol. 13, No. 9 ( 2022-09-01), p. 1402-
    Abstract: Microorganisms play a crucial role in litter decomposition in terrestrial ecosystems. The leaf and fine root litters of Robinia pseudoacacia Linn., Quercus acutissima Carr., Pinus tabulaeformis Carr. and Pinus densiflora Sieb. were analysed using the nylon litter bag method and Illumina MiSeq high-throughput sequencing for the amplification of bacterial 16S rRNA V4–V5. We assessed the effects of leaf and root litter species on the bacterial community after one year’s decomposition. The results showed that (1) the remaining mass of fine root litter was smaller than that of the leaf litter for R. pseudoacacia and Q. acutissima, while the opposite result was found for P. tabulaeformis and P. densiflora. (2) The bacterial community structure in leaf litter was most highly correlated with the initial N content and N:P, while that in fine roots was most highly correlated with the lignin content. (3) The bacterial phyla Bacteroidetes, Acidobacteria and Gemmatimonadetes were significantly affected by litter and species, whereas the relative abundances of Firmicutes and Chloroflexi were only affected by litter tissues. The relative abundances of Acidobacteria, Firmicutes and Chloroflexi in fine root litter were higher than those in leaf litter, while the opposite result was found for Bacteroidetes. The bacterial genera Burkholderia-Paraburkholderia, Sphingomonas and Mucilaginibacter were affected by litter tissues (p 〈 0.05). The relative abundance of Burkholderia-Paraburkholderia in fine root litter was higher than that in leaf litter, while the opposite result was found for Bradyrhizobium, Sphingomonas and Mucilaginibacter. Pearson’s correlation analysis showed that the relative abundances of the dominant phyla and genera were affected by the initial litter properties, especially for Bacteroides, Acidobacteria, Burkholderia and Sphingomonas. These findings indicate that litter tissues and their interactions with species are more important than the species in shaping the bacterial diversity and community composition, which was affected by the initial chemical properties of the litter.
    Type of Medium: Online Resource
    ISSN: 1999-4907
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2527081-3
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  • 2
    In: Metabolites, MDPI AG, Vol. 13, No. 2 ( 2023-02-19), p. 305-
    Abstract: High-lipid diets are attributed to excessive lipid deposition and metabolic disturbances in fish. The aim of this experiment was to investigate the effects of steroidal saponins on growth performance, immune molecules and metabolism of glucose and lipids in hybrid groupers (initial weight 22.71 ± 0.12 g) fed high-lipid diets. steroidal saponins (0%, 0.1% and 0.2%) were added to the basal diet (crude lipid, 14%) to produce three experimental diets, designated S0, S0.1 and S0.2, respectively. After an 8-week feeding trial, no significant differences were found between the S0 and S0.1 groups in percent weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and protein deposition rate (p 〉 0.05). All those in the S0.2 group were significantly decreased (p 〈 0.05). Compared to the S0 group, fish in the S0.1 group had lower contents of serum triglyceride and low-density lipoprotein cholesterol and higher high-density lipoprotein cholesterol and glucose (p 〈 0.05). The activities of superoxide dismutase, catalase and glutathione peroxidase were significantly higher, and malondialdehyde contents were significantly lower in the S0.1 group than in the S0 group (p 〈 0.05). Hepatic triglyceride, total cholesterol and glycogen were significantly lower in the S0.1 group than in the S0 group (p 〈 0.05). Activities of lipoprotein lipase, total lipase, glucokinase and pyruvate kinase, and gene expression of lipoprotein lipase, triglyceride lipase and glucokinase, were significantly higher in the S0.1 group than in the S0 group. Interleukin-10 mRNA expression in the S0.1 group was significantly higher than that in the S0 group, while the expression of interleukin-6 and tumor necrosis factor-α genes were significantly lower than those in the S0 group. In summary, adding 0.1% steroidal saponins to a high-lipid diet not only promoted lipolysis in fish livers, but also activated glycolysis pathways, thus enhancing the utilization of the dietary energy of the groupers, as well as supporting the fish’s nonspecial immune-defense mechanism.
    Type of Medium: Online Resource
    ISSN: 2218-1989
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662251-8
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  • 3
    In: Membranes, MDPI AG, Vol. 12, No. 3 ( 2022-02-27), p. 274-
    Abstract: Polymer film capacitors have been widely applied in many pulsed power fields owing to their fastest energy-released rates. The development of ferroelectric polyvinylidene fluoride (PVDF)-based composites has become one of the hot research directions in the field of high-energy storage capacitors. Recently, hierarchically-structured all-organic composites have been shown to possess excellent comprehensive energy storage performance and great potential for application. In this review, most research advances of hierarchically-structured all-organic composites for the energy storage application are systematically classified and summarized. The regulating strategies of hierarchically structured all-organic composites are highlighted from the perspective of preparation approaches, tailored material choices, layer thicknesses, and interfaces. Systematic comparisons of energy storage abilities are presented, including electric displacement, breakdown strength, energy storage density, and efficiency. Finally, we present the remaining problems of hierarchically structured all-organic composites and provide an outlook for future energy storage applications.
    Type of Medium: Online Resource
    ISSN: 2077-0375
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2614641-1
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  • 4
    In: Genes, MDPI AG, Vol. 10, No. 6 ( 2019-06-15), p. 458-
    Abstract: Hairpin-structured (hp) RNA has been widely used to induce RNA interference (RNAi) in plants and animals, and an in vivo expression system for hpRNA is important for large-scale RNAi applications. Bacterial expression systems have so far been developed for in vivo expression of hpRNA or double-stranded (ds) RNA, but the structure of the resulting RNAi molecules has remained unclear. Here we report that long hpRNAs expressed in the bacteria Escherichia coli and Sinorhizobium meliloti were largely processed into shorter dsRNA fragments with no or few full-length molecules being present. A loss-of-function mutation in the dsRNA-processing enzyme RNase III, in the widely used E. coli HT115 strain, did not prevent the processing of hpRNA. Consistent with previous observations in plants, the loop sequence of long hpRNA expressed in Agrobacterium-infiltrated Nicotiana benthamiana leaves was excised, leaving no detectable levels of full-length hpRNA molecule. In contrast to bacteria and plants, long hpRNAs expressed in the budding yeast Saccharomyces cerevisiae accumulated as intact, full-length molecules. RNA extracted from hpRNA-expressing yeast cells was shown to be capable of inducing RNAi against a β-glucuronidase (GUS) reporter gene in tobacco leaves when applied topically on leaf surfaces. Our results indicate that yeast can potentially be used to express full-length hpRNA molecules for RNAi and perhaps other structured RNAs that are important in biological applications.
    Type of Medium: Online Resource
    ISSN: 2073-4425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2527218-4
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  • 5
    Online Resource
    Online Resource
    MDPI AG ; 2023
    In:  Remote Sensing Vol. 15, No. 7 ( 2023-04-05), p. 1943-
    In: Remote Sensing, MDPI AG, Vol. 15, No. 7 ( 2023-04-05), p. 1943-
    Abstract: The optimum placement of receiving telescope antennas is a central topic for designing radio interferometric arrays, and this determines the performance of the obtained information. A variety of arrays are designed for different purposes, and they perform poorly in scalability. In this paper, we consider a subclass of structured sparse arrays, namely nested arrays, and examine the important role of “coarray” in interferometric synthesis imaging, which is utilized to design nested array configurations for a complete uniform Fourier plane coverage in both supersynthesis and instantaneous modes. Both nested arrays and the theory of the coarray have rich research achievements, and we apply them to astronomy to design arrays with good scalability and imaging performance. Simulated celestial source image retrieval performance validates the effectiveness of nested interferometric arrays.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2513863-7
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  • 6
    In: Actuators, MDPI AG, Vol. 11, No. 8 ( 2022-08-06), p. 225-
    Abstract: In order to solve the problems of limited installation space and strict additional quality, the effects of internal distributed nonlinear energy sinks (NES) considering optimal locations on a composite truss core sandwich plate are investigated in this paper. Choose five NESs here and inset them in the different places of the sandwich plate to suppress the vibration of the plate, which is excited by a half-wave shock. The coupled dynamic equations of the system are derived by the principle of conservation of energy. Then, the vibration-control performances of five NESs are discussed by numerical simulation. The distributions of the five NESs are analyzed, and the optimal position distributions are obtained. Based on the optimal location, the transient responses of the system are studied. Moreover, the performances of five NESs and a single NES are compared in different dimensions. Finally, it is found that the selection of parameters has a great impact on the effectiveness of the five NESs. The new distribution way is introduced to improve the suppression effects of the five NESs in the sandwich plate.
    Type of Medium: Online Resource
    ISSN: 2076-0825
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2682469-3
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  • 7
    In: Nanomaterials, MDPI AG, Vol. 10, No. 5 ( 2020-05-15), p. 946-
    Abstract: The high overpotentials for oxygen reduction reaction (ORR) create an extremely negative impact on the energy efficiency of the air-based battery systems. To overcome this problem, binuclear ball-type metallophthalocyanines containing methoxy substituents (M2Pc2(EP)4, M = Fe(II), Co(II) and Zn(II)) were wrapped with polystyrene sodium sulfonate (PSS) modified graphene oxide (GO), using a facilely “solvothermal π-π assembly” method to prepare M2Pc2(EP)4/PSS-Gr composites. Compared with the commercial Pt/C catalysts, the M2Pc2(EP)4/PSS-Gr composites enhanced the catalytic activity of oxygen reduction reaction. The π electron conjugated structure of the MN4-type phthalocyanine macrocyclic system strongly influenced the one-step four-electron electrocatalytic process of the M2Pc2(EP)4/PSS-Gr composites. Moreover, the π-π interactions between the M2Pc2(EP)4 and PSS-Gr dramatically enhanced the π electron density in the conjugated structure and oxygen could be reduced more easily. The electrocatalytic activity test was displayed in the order of Fe2Pc2(FP)4/PSS-Gr 〉 Co2Pc2(EP)4/PSS-Gr 〉 Zn2Pc2(EP)4/PSS-Gr. The results indicated that the catalytic performance of M2Pc2Rn could be enhanced by the modification of π electron conjugated structure of M2Pc2(EP)4 and carbon materials.
    Type of Medium: Online Resource
    ISSN: 2079-4991
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662255-5
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  • 8
    In: Remote Sensing, MDPI AG, Vol. 13, No. 16 ( 2021-08-19), p. 3280-
    Abstract: The accuracy and applications of synthetic aperture radar interferometry (InSAR) are severely suppressed by tropospheric error. Numerical Weather Models (NWMs) and GPS-derived tropospheric delays have been widely used to correct the tropospheric error considering their complete spatial coverage or high accuracy. However, few studies focus on the fusion of both NWMs and GPS for the tropospheric error correction. In this study, we used the Weather Research and Forecasting (WRF) to obtain NWMs with a higher spatial-temporal resolution of 3 km and 20 s from both ERAI (79 km and 6 h) and ERA5 (0.25° and 1 h). After that, we utilized the WRF Data Assimilation (WRFDA) system to assimilate the GPS ZTD into these enhanced NWMs and generate merged NWMs products. The tropospheric correction effectiveness from different NWMs products was evaluated in a case in the Pearl River Delta region of China. The results showed that all the NWMs products could correct the stratified component in the interferogram but could not mitigate the turbulence well, even after improving the spatial-temporal resolution. As for the trend component, the merged NWMs products showed obvious superiority over other products. From the statistics perspective, the stdev of the interferogram decreased further over 20% by the merged NWMs products than other products when using both ERAI and ERA5, indicating the significant effectiveness of GPS ZTD assimilation.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2513863-7
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  • 9
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Remote Sensing Vol. 14, No. 19 ( 2022-09-26), p. 4807-
    In: Remote Sensing, MDPI AG, Vol. 14, No. 19 ( 2022-09-26), p. 4807-
    Abstract: The asymmetric delay has a considerable impact on Global Navigation Satellite Systems (GNSS) Positioning, Navigation and Timing (PNT) applications. In GNSS analyses, the impacts of the asymmetric delay are commonly compensated by using the classical methods with considering the north-south and east-west horizontal gradients. In this paper, we have initiatively proposed an extended method where the north-south and east-west horizontal gradients as well as the second-order horizontal gradients are included to better fit the asymmetric delay. The modeling accuracy of the extended method was evaluated at globally distributed 905 GNSS stations during 40 days in 2020. Significant performance of the extended method respect to the classical method was found, where the hydrostatic and wet modeling accuracy at 4° elevation angle was improved from 5.3 and 10.6 mm to 1.6 and 4.9 mm by 70% and 54%, respectively. The GNSS Precise Point Positioning (PPP) performance using the extended method was also validated at 107 Multi-GNSS Experiment (MGEX) stations. The superior performance on the coordinate repeatability and significant effectiveness on the coordinate and Zenith Total Delay (ZTD) estimations were also found, and the maximal vertical (U) coordinate and ZTD difference biases reached 8.6 and −4.5 mm. The extended method is therefore recommended to substitute the classical methods in the GNSS analyses, especially under severe atmospheric conditions.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2513863-7
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  • 10
    In: Sensors, MDPI AG, Vol. 18, No. 8 ( 2018-08-01), p. 2484-
    Abstract: Traditional methods of detecting and mapping utility poles are inefficient and costly because of the demand for visual interpretation with quality data sources or intense field inspection. The advent of deep learning for object detection provides an opportunity for detecting utility poles from side-view optical images. In this study, we proposed using a deep learning-based method for automatically mapping roadside utility poles with crossarms (UPCs) from Google Street View (GSV) images. The method combines the state-of-the-art DL object detection algorithm (i.e., the RetinaNet object detection algorithm) and a modified brute-force-based line-of-bearing (LOB, a LOB stands for the ray towards the location of the target [UPC at here] from the original location of the sensor [GSV mobile platform] ) measurement method to estimate the locations of detected roadside UPCs from GSV. Experimental results indicate that: (1) both the average precision (AP) and the overall accuracy (OA) are around 0.78 when the intersection-over-union (IoU) threshold is greater than 0.3, based on the testing of 500 GSV images with a total number of 937 objects; and (2) around 2.6%, 47%, and 79% of estimated locations of utility poles are within 1 m, 5 m, and 10 m buffer zones, respectively, around the referenced locations of utility poles. In general, this study indicates that even in a complex background, most utility poles can be detected with the use of DL, and the LOB measurement method can estimate the locations of most UPCs.
    Type of Medium: Online Resource
    ISSN: 1424-8220
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2052857-7
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