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  • MDPI AG  (150)
  • 1
    Online Resource
    Online Resource
    Forest Height Inversion via RVoG Model and Its Uncertainties Analysis via Bayesian Framework—Comparisons of Different Wavelengths and Baselines
    MDPI AG ; 2023
    In:  Forests Vol. 14, No. 7 ( 2023-07-10), p. 1408-
    Details
    In: Forests, MDPI AG, Vol. 14, No. 7 ( 2023-07-10), p. 1408-
    Abstract: Accurate estimation of forest height over a large area is beneficial to reduce the uncertainty of forest carbon sink estimation, which is of great significance to the terrestrial carbon cycle, global climate change, forest resource management, and forest-related scientific research. Forest height inversion using polarimetric interferometry synthetic aperture radar (PolInSAR) data through Random volume over ground (RVoG) models has demonstrated great potential for large-area forest height mapping. However, the wavelength and baseline length used for the PolInSAR data acquisition plays an important role during the forest height estimation procedure. In this paper, X–, C–, L–, and P–band PolInSAR datasets with four different baseline lengths were simulated and applied to explore the effects of wavelength and baseline length on forest height inversion using RVoG models. Hierarchical Bayesian models developed with a likelihood function of RVoG model were developed for estimated results uncertainty quantification and decrease. Then a similar procedure was applied in the L– and P–band airborne PolInSAR datasets with three different baselines for each band. The results showed that (1) Wavelength showed obvious effects on forest height inversion results with the RVoG model. For the simulated PolInSAR datasets, the L– and P–bands performed better than the X– and C–bands. The best performance was obtained at the P–band with a baseline combination of 10 × 4 m with an absolute error of 0.05 m and an accuracy of 97%. For the airborne PolInSAR datasets, an L–band with the longest baseline of 24 m in this study showed the best performance with R2 = 0.64, RMSE = 3.32 m, and Acc. = 77.78%. (2) It is crucial to select suitable baseline lengths to obtain accurate forest height estimation results. In the four baseline combinations of simulated PolInSAR datasets, the baseline combination of 10 × 4 m both at the L– and P–bands performed best than other baseline combinations. While for the airborne PolInSAR datasets, the longest baseline in three different baselines obtained the highest accuracy at both L– and P–bands. (3) Bayesian framework is useful for estimation results uncertainty quantification and decrease. The uncertainties related to wavelength and baseline length. The uncertainties were reduced obviously at longer wavelengths and suitable baselines.
    Type of Medium: Online Resource
    ISSN: 1999-4907
    URL: Article
    DOI: 10.3390/f14071408
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2527081-3
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  • 2
    Online Resource
    Online Resource
    Influence of Different Heat Loads and Durations on the Field Thermal Response Test
    MDPI AG ; 2022
    In:  Energies Vol. 15, No. 22 ( 2022-11-21), p. 8759-
    Details
    In: Energies, MDPI AG, Vol. 15, No. 22 ( 2022-11-21), p. 8759-
    Abstract: Geothermal energy exhibits considerable development potential in space heating. Shallow geothermal energy stored in the soil in the form of low-grade energy is mainly extracted via the ground source heat pump (GSHP) system. GSHP systems use the subsoil as a heat source, typically involving a vertical borehole heat exchanger (BHE) to extract heat from the formation. Accurate measurement of the thermal properties of the formation is very important for the design of BHEs. At present, the most common and effective method to measure the thermal conductivity of the formation in the field is the thermal response test (TRT). However, the test conditions (heat load, test time) during the thermal response test can impact the test results. Therefore, in this study, a borehole with a depth of 130 m was evaluated in the field. The TRT module and the distributed thermal response test (DTRT) module based on distributed optical fiber temperature sensor (DOFTS) technology were used to monitor the test with different working conditions in real-time. In the field tests, geothermal conditions and the evolution of the formation temperature with time and depth were determined. Based on the test results under different heat loads and test times, the influence of the test conditions on the thermal conductivity results was analyzed and described. A constant temperature zone was located at a depth from 25 m to 50 m, and an increasing temperature zone was located at a depth from 50 m to 130 m, with a geothermal gradient of 3 °C/100 m. The results showed that the heat load slightly influenced the thermal conductivity test results. At the initial stage of the test, the temperature significantly increased from 0 to 12 h. After reaching the quasi-stable state, the test time slightly influenced the thermal conductivity test results. The characteristics of the formation thermal recovery stage after the test stage were studied. The heat load decreased, which could shorten the time for the formation to recover the initial temperature. The results could provide a basis for the optimization of thermal response test conditions.
    Type of Medium: Online Resource
    ISSN: 1996-1073
    URL: Article
    DOI: 10.3390/en15228759
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2437446-5
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  • 3
    Online Resource
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    An Easily Fabricated Electrochemical Sensor Based on a Graphene-Modified Glassy Carbon Electrode for Determination of Octopamine and Tyramine
    MDPI AG ; 2016
    In:  Sensors Vol. 16, No. 4 ( 2016-04-13), p. 535-
    Details
    In: Sensors, MDPI AG, Vol. 16, No. 4 ( 2016-04-13), p. 535-
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s16040535
    Language: English
    Publisher: MDPI AG
    Publication Date: 2016
    detail.hit.zdb_id: 2052857-7
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  • 4
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    Online Resource
    Identification of Signatures of Selection for Litter Size and Pubertal Initiation in Two Sheep Populations
    MDPI AG ; 2022
    In:  Animals Vol. 12, No. 19 ( 2022-09-21), p. 2520-
    Details
    In: Animals, MDPI AG, Vol. 12, No. 19 ( 2022-09-21), p. 2520-
    Abstract: Fecundity is an important economic trait in sheep that directly affects their economic and productive efficiency. Our study aimed to identify SNP loci associated with sheep puberty or litter size which could be used in future breeding programs to improve fertility. Genomic DNA was obtained from Hetian and Cele Black sheep breeds and used for reduced-representation genome sequencing to identify SNP loci associated with pubertal initiation and litter size. Selective signatures analysis was performed based on the fixation index and nucleotide diversity, followed by pathway analysis of the genes contained in the selected regions. The selected SNP loci in the genes associated with pubertal initiation and litter size were validated using both sheep breeds. In total, 384,718 high quality SNPs were obtained and 376 genes were selected. Functional annotation of genes and enrichment analysis identified 12 genes associated with pubertal initiation and 11 genes associated with litter size. SNP locus validation showed that two SNP on PAK1 and four on ADCY1 may be associated with pubertal initiation, and one SNP on GNAQ gene (NC_040253.1: g.62677376G 〉 A) was associated with litter size in Cele Black sheep. Our results provide new theoretical support for sheep breeding.
    Type of Medium: Online Resource
    ISSN: 2076-2615
    URL: Article
    DOI: 10.3390/ani12192520
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2606558-7
    SSG: 23
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  • 5
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    Genome-Wide Identification and Expression Profiling Analysis of the Long-Chain Acyl-CoA Synthetases Reveal Their Potential Roles in Wheat Male Fertility
    MDPI AG ; 2022
    In:  International Journal of Molecular Sciences Vol. 23, No. 19 ( 2022-10-08), p. 11942-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 19 ( 2022-10-08), p. 11942-
    Abstract: Long-chain acyl-CoA synthetase (LACS), responsible for the conversion of free FAs into acyl-CoAs, is involved in multiple pathways of lipid metabolism. Although LACS genes in Arabidopsis have been well characterized, no detailed information concerning this family is available for wheat. In the present study, a systematic analysis was carried out for the wheat LACS family. As a result, 30 putative TaLACSs were identified. Expression analysis revealed that 22 Takacs were expressed in wheat anthers. Two orthologs of AtLACS1, TaLACS2 and TaLACS3, were repressed at the vacuolated stage in the cold-treated BS366 (a temperature-sensitive genic male-sterile line). Thus, TaLACS2 and TaLACS3 may function like AtLACS1 in wax biosynthesis in anthers, and the repression of both genes may be correlated with the male sterility of BS366. TaLACS5 is an ortholog of AtLACS5, which was expressed exclusively in anthers. TaLACS5 was repressed in the cold-treated BS366 at the tetrad, uninucleate, and vacuolated stages. The negative correlation between TaLACS5 and TaGAMYB-B, and the MYB domain found in the promoter sequence suggested that TaLACS5 may be negatively regulated by TaGAMYB-B to participate in wheat fertility. These findings will provide a valuable foundation for the understanding of the wheat LACS gene family in male fertility.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms231911942
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 6
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    Assessing Approaches of Human Inhalation Exposure to Polycyclic Aromatic Hydrocarbons: A Review
    MDPI AG ; 2021
    In:  International Journal of Environmental Research and Public Health Vol. 18, No. 6 ( 2021-03-18), p. 3124-
    Details
    In: International Journal of Environmental Research and Public Health, MDPI AG, Vol. 18, No. 6 ( 2021-03-18), p. 3124-
    Abstract: Polycyclic aromatic hydrocarbons (PAHs) are a class of important organic pollutants widely emitted from anthropogenic activities, with a general distribution in the gas and particulate phases. Some PAHs are carcinogenic, teratogenic, and mutagenic. Inhalation exposure to PAHs is correlated with adverse health outcomes in the respiratory and cardiovascular systems. Thus, it is significant to determine the exposure level of the general population. This study summarizes the evaluation methods for PAH exposure, focusing on different exposure parameters. External exposure can be determined via the collection of the environmental pollution concentration through active samplers or passive samplers during environmental monitoring or personal sampling. Time-activity patterns give critical exposure information that captures the exposure period, origin, and behaviors. Modeling is a labor-less approach for human exposure estimation, and microenvironmental exposure requires specific research. It is important to select appropriate methods to quantify the exposure level to provide accurate data to establish the exposure–risk relationship and make scientific suggestions for the protection of public health.
    Type of Medium: Online Resource
    ISSN: 1660-4601
    URL: Article
    DOI: 10.3390/ijerph18063124
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2175195-X
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  • 7
    Online Resource
    Online Resource
    Integrated Analysis of Microarray, Small RNA, and Degradome Datasets Uncovers the Role of MicroRNAs in Temperature-Sensitive Genic Male Sterility in Wheat
    MDPI AG ; 2022
    In:  International Journal of Molecular Sciences Vol. 23, No. 15 ( 2022-07-22), p. 8057-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 15 ( 2022-07-22), p. 8057-
    Abstract: Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms23158057
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 8
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    Online Resource
    Fluorescent Probe Combined with Photoelectric Analysis Technology for Detection of Escherichia coli
    MDPI AG ; 2023
    In:  Biosensors Vol. 13, No. 2 ( 2023-01-18), p. 150-
    Details
    In: Biosensors, MDPI AG, Vol. 13, No. 2 ( 2023-01-18), p. 150-
    Abstract: Food safety is facing great challenges in preventing foodborne diseases caused by pathogenic pollution, especially in resource-limited areas. The rapid detection technique of microorganisms, such as immunological methods and molecular biological methods, plays a crucial key in timely bioanalysis and disease treatment strategies. However, it is difficult for these methods to simultaneously meet the criteria of simple operation, high specificity, and sensitivity, as well as low cost. Coconut water is known as the “water of life” in Hainan. It is a refreshing and nutritious beverage which is widely consumed due to its beneficial properties to health. Coconut water processing is an important pillar industry in Hainan. The detection of pathogenic microorganisms, such as Escherichia coli, in coconut water has become an important factor which has restricted the upgrading and development of this industry. Based on the needs of industrial development, we developed a microbial photoelectric detection system which was composed of a fluorescent probe detection reagent and a photoelectric sensor detection device. This system combined microbial enzyme targets, selective fluorescent substrate metabolism characteristics, and a photoelectric sensor signal transduction mechanism, which produce a strong signal with a high signal-to-noise ratio. The microbial detection system developed here has a simple structure, simple and convenient operation, short detecting time (≥2 h), and high sensitivity (1 CFU/mL). This system may also enable early warning and monitoring programs for other pathogenic microorganisms in order to promote the overall competitiveness of the Hainan coconut water industry.
    Type of Medium: Online Resource
    ISSN: 2079-6374
    URL: Article
    DOI: 10.3390/bios13020150
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662125-3
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  • 9
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    Online Resource
    Analysis of Crash Characteristics of Hydrogen Storage Structure of Hydrogen Powered UAV
    MDPI AG ; 2022
    In:  Aerospace Vol. 9, No. 11 ( 2022-11-04), p. 687-
    Details
    In: Aerospace, MDPI AG, Vol. 9, No. 11 ( 2022-11-04), p. 687-
    Abstract: In the context of green aviation, as an internationally recognized solution, hydrogen energy is lauded as the “ultimate energy source of the 21st century”, with zero emissions at the source. Developed economies with aviation industries, such as Europe and the United States, have announced hydrogen energy aviation development plans successively. The study and development of high-energy hydrogen fuel cells and hydrogen energy power systems have become some of the future aviation research focal points. As a crucial component of hydrogen energy storage and delivery, the design and development of a safe, lightweight, and efficient hydrogen storage structure have drawn increasing consideration. Using a hydrogen-powered Unmanned Aerial Vehicle (UAV) as the subject of this article, the crash characteristics of the UAV’s hydrogen storage structure are investigated in detail. The main research findings are summarized as follows: (1) A series of crash characteristics analyses of the hydrogen storage structure of a hydrogen-powered UAV were conducted, and the Finite Element Analysis (FEA) response of the structure under different impact angles, internal pressures, and impact speeds was obtained and analyzed. (2) When the deformation of the hydrogen storage structure exceeds 50 mm, and the strain exceeds 0.8, an initial crack will appear at this part of the hydrogen storage structure. The emergency release valve should respond immediately to release the gas inside the tank to avoid further damage. (3) Impact angle and initial internal pressure are the main factors affecting the formation of initial cracks.
    Type of Medium: Online Resource
    ISSN: 2226-4310
    URL: Article
    DOI: 10.3390/aerospace9110687
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2756091-0
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  • 10
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    Effects of Freezing Temperature and Salinity on the Adhesion Shear Strength of Amphibious Aircraft Tires under Static Icing
    MDPI AG ; 2022
    In:  Aerospace Vol. 9, No. 3 ( 2022-03-20), p. 170-
    Details
    In: Aerospace, MDPI AG, Vol. 9, No. 3 ( 2022-03-20), p. 170-
    Abstract: This research investigates the effects of freezing temperature and salinity on the adhesion shear strength of amphibious aircraft tires under static icing. It found that the lower the freezing temperature, the greater the ice adhesion shear strength, and the higher the salinity of the water sample, the lower the ice adhesion shear strength. This is related to the thickness of the brine layer at the ice-tire substrate interface; the temperature decreased, the brine layer became thinner, and, accordingly, the adhesion shear strength increased. This paper analyzes the problem of brine precipitation during seawater freezing and its influencing mechanism on the ice adhesion shear strength. In addition, it also found that the lower the temperature, the greater the growth rate of the ice adhesion shear strength. When the salinity in different ranges changed, its influence on the adhesion shear strength was different. When the salinity of the water sample is close to 0%, a small change in the salinity will cause a large change in the ice adhesion shear strength. When the salinity is large, the change of salinity has a weaker influence on the ice adhesion shear strength. This research provides a strong reference for the design and study of amphibious aircraft tires.
    Type of Medium: Online Resource
    ISSN: 2226-4310
    URL: Article
    DOI: 10.3390/aerospace9030170
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2756091-0
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