bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytogenomics of Deschampsia P. Beauv. (Poaceae) Species Based on Sequence Analyses and FISH Mapping of CON/COM Satellite DNA Families
Authors: Amosova Alexandra V. , Ghukasyan Lilit , Yurkevich Olga Yu. , Bolsheva Nadezhda L. , Samatadze Tatiana E. , Zoshchuk Svyatoslav A. , Muravenko Olga V.
Published: May 2021

The genus Deschampsia P. Beauv. (Poaceae) involves a group of widespread polymorphic species, and many of them are highly tolerant to stressful environmental conditions. Genome diversity and chromosomal phylogeny within the genus are still insufficiently studied. Satellite DNAs, including CON/COM families, are the main components of the plant repeatome, which contribute to chromosome organization. For the first time, using PCR-based (Polymerase Chain Reaction) techniques and sequential BLAST (Basic Local Alignment Search Tool) and MSA (Multiple Sequence Alignment) analyses, we identified and classified CON/COM repeats in genomes of eleven Deschampsia accessions and three accessions from related genera. High homology of CON/COM sequences were revealed in the studied species though differences in single-nucleotide alteration profiles detected in homologous CON/COM regions indicated that they tended to diverge independently. The performed chromosome mapping of 45S rDNA, 5S rDNA, and CON/COM repeats in six Deschampsia species demonstrated interspecific variability in localization of these cytogenetic markers and facilitated the identification of different chromosomal rearrangements. Based on the obtained data, the studied Deschampsia species were distinguished into karyological groups, and MSA-based schematic trees were built, which could clarify the relationships within the genus. Our findings can be useful for further genetic and phylogenetic studies.
Potential Toxicity of Medicinal Plants Inventoried in Northeastern Morocco: An Ethnobotanical Approach
Authors: Kharchoufa Loubna , Bouhrim Mohamed , Bencheikh Noureddine , Addi Mohamed , Hano Christophe , Mechchate Hamza , Elachouri Mostafa
Published: May 2021

Herbal medicine and its therapeutic applications are widely practiced in northeastern Morocco, and people are knowledgeable about it. Nonetheless, there is a significant knowledge gap regarding their safety. In this study, we reveal the toxic and potential toxic species used as medicines by people in northeastern Morocco in order to compile and document indigenous knowledge of those herbs. Structured and semi-structured interviews were used to collect data, and simple random sampling was used as a sampling technique. Based on this information, species were collected, identified, and herbarium sheets were created. The collected data were analyzed using two quantitative indices: informant consensus factor (ICF) and fidelity level (Fl), as the degree of these indices give an insight into the level of toxicity of a given plant. The results revealed the knowledge of 55 species belonging to 36 families. The most represented families were Apiaceae, Asteraceae, Solanaceae, and Fabaceae. Furthermore, the majority of the species cited were herbs (67%), and the most common toxic parts were seeds, followed by leaves and roots. According to the informant consensus factor, death (0.81%) had the highest agreement, followed by the urological (0.76%) and skin (0.75%) categories. The most significant plants in terms of fidelity level were Solanum sodomaeum L. and Nerium oleander L. for death, Arisarum vulgare O. Targ. Tozz., Mentha spicata L., and Morus alba L. for the digestive category, Petroselinum crispum (Mill.) Fuss. and Citrus x aurantium L. for cardiovascular category, Urtica dioica L. for skin category, Datura stramonium L, and Ephedra altissima Desf. for neurological category, and finally Crocus sativus L. for general and unspecified category. This work highlights a valuable traditional knowledge of poisonous and potential poisonous plants in northeastern Morocco. Further phytochemical and toxicological research is needed to determine the safety of these prized herbs.
Process Development for Flexible Films of Industrial Cellulose Pulp Using Superbase Ionic Liquids
Authors: Ribeiro Diana C. M. , Rebelo Rafael C. , De Bon Francesco , Coelho Jorge F. J. , Serra Arménio C.
Published: May 2021

Due to environmental concerns, more attention has been given to the development of bio-based materials for substitution of fossil-based ones. Moreover, paper use is essential in daily routine and several applications of industrial pulp can be developed. In this study, transparent films were produced by industrial cellulose pulp solubilization in tetramethylguanidine based ionic liquids followed by its regeneration. Films were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), UV/Vis spectroscopy, proton nuclear magnetic resonance (1H-NMR), dynamic scanning calorimetry (DSC), thermal analysis (TG), and X-ray diffraction (XRD). Mechanical tests showed that films have a good elongation property, up to 50%, depending on ionic liquid incorporation. The influence of the conjugated acid and dissolution temperature on mechanical properties were evaluated. These results revealed the potential of this methodology for the preparation of new biobased films.
Numerical Study Using Microstructure Based Finite Element Modeling of the Onset of Convective Heat Transfer in Closed-Cell Polymeric Foam
Authors: Rivera-Salinas Jorge-Enrique , Gregorio-Jáuregui Karla-Monzerratt , Fonseca-Florido Heidi-Andrea , Ávila-Orta Carlos-Alberto , Ramírez-Vargas Eduardo , Romero-Serrano José-Antonio , Cruz-Ramírez Alejandro , Gutierréz-Pérez Víctor-Hugo , Olvera-Vazquez Seydy-Lizbeth , Rosales-Marines Lucero
Published: May 2021

The thermal performance of closed-cell foams as an insulation device depends on the thermal conductivity. In these systems, the heat transfer mode associated with the convective contribution is generally ignored, and studies are based on the thermo-physical properties that emerge from the conductive contribution, while others include a term for radiative transport. The criterion found in the literature for disregarding convective heat flux is the cell diameter; however, the cell size for which convection is effectively suppressed has not been clearly disclosed, and it is variously quoted in the range 3–10 mm. In practice, changes in thermal conductivity are also attributed to the convection heat transfer mode; hence, natural convection in porous materials is worthy of research. This work extends the field of study of conjugate heat transfer (convection and conduction) in cellular materials using microstructure-based finite element analysis. For air-based insulating materials, the criteria to consider natural convection (Ra=103) is met by cavities with sizes of 9.06 mm; however, convection is developed into several cavities despite their sizes being lower than 9.06 mm, hence, the average pore size that can effectively suppress the convective heat transfer is 6.0 mm. The amount of heat transported by convection is about 20% of the heat transported by conduction within the foam in a Ra=103, which, in turn, produces an increasing average of the conductivity of about 4.5%, with respect to a constant value.
Viscoelastic Relaxation of Polymerized Ionic Liquid and Lithium Salt Mixtures: Effect of Salt Concentration
Authors: Yokokoji Arisa , Kitayama Wakana , Wichai Kamonthira , Urakawa Osamu , Matsumoto Atsushi , Vao-Soongnern Visit , Inoue Tadashi
Published: May 2021

Polymerized ionic liquids (PILs) doped with lithium salts have recently attracted research interests as the polymer component in lithium-ion batteries because of their high ionic mobilities and lithium-ion transference numbers. To date, although the ion transport mechanism in lithium-doped PILs has been considerably studied, the role of lithium salts on the dynamics of PIL chains remains poorly understood. Herein, we examine the thermal and rheological behaviors of the mixture of poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide (PC4-TFSI)/lithium TFSI (LiTFSI) in order to clarify the effect of the addition of LiTFSI. We show that the glass transition temperature Tg and the entanglement density decrease with the increase in LiTFSI concentration wLiTFSI. These results indicate that LiTFSI acts as a plasticizer for PC4-TFSI. Comparison of the frequency dependence of the complex modulus under the iso-frictional condition reveals that the addition of LiTFSI does not modify the stress relaxation mechanism of PC4-TFSI, including its characteristic time scale. This suggests that the doped LiTFSI, component that can be carrier ions, is not so firmly bound to the polymer chain as it modifies the chain dynamics. In addition, a broadening of the loss modulus spectrum in the glass region occurs at high wLiTFSI. This change in the spectrum can be caused by the responses of free TFSI and/or coordination complexes of Li and TFSI. Our detailed rheological analysis can extract the information of the dynamical features for PIL/salt mixtures and may provide helpful knowledge for the control of mechanical properties and ion mobilities in PILs.
Adsorption Characteristics of Polymer Solutions on Media Surfaces and Their Main Influencing Factors
Authors: Zhu Shijie , Ye Zhongbin , Liu Zhezhi , Chen Zhonghua , Li Jun , Xiang Zuping
Published: May 2021

In practical applications, the chemical and physical adsorption of a polymer solution greatly affects its action mode and effect. Understanding the adsorption mechanism and its influencing factors can help to optimize the application mode and ensure application efficiency. Three types of polymer solutions—partially hydrolyzed polyacrylamide (HPAM), hydrophobically associating polymer (AP-P4), and dendrimer hydrophobically associating polymer (DHAP), which are viscoelastic liquids—were used as sorbates to study their adsorption by a sorbent such as quartz sand. The effects of the solution concentration, contact time, particle size of quartz sand, solid–liquid ratio, and fluid movement on the adsorption capacity of the polymer solutions were examined. The results showed that HPAM presents a typical Langmuir monolayer adsorption characteristic, and its adsorption capacity (per unit area) is 1.17–1.62 μg/cm2. The association enhances the interactions of the AP-P4 and DHAP solutions, and they present multilayer characteristics of first-order chemical adsorption and secondary physical molecule adsorption. Moreover, the dendrite structure further increases the adsorption thickness of DHAP. Hence, the adsorption thicknesses of AP-P4 and DHAP are four and six times that of HPAM, respectively. The adsorption of the three polymers is consistent with the influence of fluid motion and decreases with increasing fluid velocity. However, the larger the thickness of the adsorption layer, the clearer the influence of the flow, and the higher the decrease in adsorption capacity. Optimizing the injection rate is an effective method to control the applications of a polymer in porous media.
Development of Nanocomposite Film Comprising of Polyvinyl Alcohol (PVA) Incorporated with Bacterial Cellulose Nanocrystals and Magnetite Nanoparticles
Authors: Usawattanakul Naphat , Torgbo Selorm , Sukyai Prakit , Khantayanuwong Somwang , Puangsin Buapan , Srichola Preeyanuch
Published: May 2021

Nanocomposite film of poly(vinyl alcohol) (PVA) incorporated with bacterial cellulose nanocrystals (BCNCs) and magnetite nanoparticles (Fe3O4) is reported in this study. The BCNC-Fe3O4 nanoparticles and PVA film was prepared by in situ synthesis technique using chemical co-precipitation. Different concentrations of BCNC-Fe3O4 (20%, 40% and 60% w/w) were mechanically dispersed in PVA solution to form the nanocomposite film. Transmission electron microscopy (TEM) analysis of BCNC-Fe3O4 nanoparticles showed irregular particle sizes ranging from 4.93 to 30.44 nm with an average size distribution of 22.94 nm. The presence of characteristic functional groups of PVA, BCNC and Fe3O4 were confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Scanning electron microscope (SEM) attached energy dispersive spectroscopy (EDS) and vibrating sample magnetometer (VSM) analysis revealed that, the iron content and magnetic property increased with increasing BCNC-Fe3O4 content. The saturation magnetizations (MS) value increased from 5.14 to 11.56 emu/g. The PVA/ BCNC-Fe3O4 at 60% showed the highest Young’s modulus value of 2.35 ± 0.16 GPa. The prepared film could be a promising polymeric nanomaterial for various magnetic-based applications and for the design of smart electronic devices.
Thermo-Mechanical Behavior of Poly(ether ether ketone): Experiments and Modeling
Authors: Drozdov A. D. , deClaville Christiansen J.
Published: May 2021

Observations are reported on poly(ether ether ketone) (PEEK) in uniaxial tensile tests, relaxation tests and creep tests with various stresses in a wide interval of temperatures ranging from room temperature to 180 °C. Constitutive equations are developed for the thermo–mechanical behavior of PEEK under uniaxial deformation. Adjustable parameters in the governing equations are found by matching the experimental data. Good agreement is demonstrated between the observations and results of numerical simulation. It is shown that the activation energies for the elastoplastic, viscoelastic and viscoelastoplastic responses adopt similar values at temperatures above the glass transition point.
Polysaccharide Derived from Nelumbo nucifera Lotus Plumule Shows Potential Prebiotic Activity and Ameliorates Insulin Resistance in HepG2 Cells
Authors: Le Bao , Anh Pham-Thi-Ngoc , Yang Seung-Hwan
Published: May 2021

Polysaccharides are key bioactive compounds in lotus plumule tea, but their anti-diabetes activities remain unclear. The purpose of this study was to investigate the prebiotic activities of a novel polysaccharide fraction from the Nelumbo nucifera lotus plumule, and to examine its regulation of glucose metabolism in insulin-resistant HepG2 cells. The N. nucifera polysaccharide (NNP) was purified after discoloration, hot water extraction, ethanol precipitation, and DEAE-cellulose chromatography to obtain purified polysaccharide fractions (NNP-2). Fourier transform infrared spectroscopy was used to analyze the main structural characteristics and functional group of NNP-2. Physicochemical characterization indicated that NNP-2 had a molecular weight of 110.47 kDa and consisted of xylose, glucose, fructose, galactose, and fucose in a molar ratio of 33.4:25.7:22.0:10.5:8.1. The prebiotic activity of NNP-2 was demonstrated in vitro using Lactobacillus and Bifidobacterium. Furthermore, NNP-2 showed bioactivity against α-glucosidase (IC50 = 97.32 µg/mL). High glucose-induced insulin-resistant HepG2 cells were used to study the effect of NNP-2 on glucose consumption, and the molecular mechanism of the insulin transduction pathway was studied using RT-qPCR. NNP-2 could improve insulin resistance by modulating the IRS1/PI3K/Akt pathway in insulin-resistant HepG2 cells. Our data demonstrated that the Nelumbo nucifera polysaccharides are potential sources for nutraceuticals, and we propose functional food developments from the bioactive polysaccharides of N. nucifera for the management of diabetes.
Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes
Authors: Tolmachev Dmitry , Mamistvalov George , Lukasheva Natalia , Larin Sergey , Karttunen Mikko
Published: May 2021

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.
Recent Advances in Elongational Flow Dominated Polymer Processing Technologies
Authors: Yuan Zhongke , Chen Xiaochuan , Yu Dingshan
Published: May 2021

The continuous development of plasticizing conveying methods and devices has been carried out to meet the needs of the polymer processing industry. As compared to the conventional shear-flow-dominated plasticizing and conveying techniques, a new method for processing polymers based on elongational flow was proposed. This new method and the related devices such as vane extruders, eccentric rotor extruders and so on, exhibited multiple advantages including shorter processing time, higher mixing effectiveness, improved product performance and better adaptability to various material systems. The development of new techniques in the field of polymer material processing has opened up a broad space for the development of new plastic products, improved product performance and reduced processing costs. In this review, recent advances concerning the processing techniques based on elongational flow are summarized, and the broad applications in polymer processing as well as some future opportunities and challenges in this vibrant area are elucidated in detail.
A Novel Formulation of Cisplatin with γ-Polyglutamic Acid and Chitosan Reduces Its Adverse Renal Effects: An In Vitro and In Vivo Animal Study
Authors: Sasai Masao , Sakura Kazuma , Matsuda Takayuki , Uyama Hiroshi
Published: May 2021

Cisplatin (cis-diamminedichloroplatinum (II); CDDP) is a key chemotherapeutic agent but causes renal damage and other off-target effects. Here, we describe the pharmacological and biochemical characteristics of a novel formulation of CDDP complexed with γ-polyglutamic acid (γ-PGA) and chitosan (CS), γ-PGA/CDDP-CS, developed by complexing CDDP with γ-PGA, then adding CS (15 kDa; 10 mol%/γ-PGA). We analyzed tumor cytotoxicity in vitro, as well as blood kinetics, acute toxicity, and antitumor efficacy in vivo in BALB/cAJcl mice. γ-PGA/CDDP-CS showed pH-dependent release in vitro over 12 days (9.1% CDDP released at pH 7.4; 49.9% at pH 5.5). It showed in vitro cytotoxicity in a dose-dependent manner similar to that of uncomplexed CDDP. In a mesothelioma-bearing mouse model, a 15 mg/kg dose of CDDP inhibited tumor growth regardless of the type of formulation, complexed or uncomplexed; however, all mice in the uncomplexed CDDP group died within 13 days. γ-PGA/CDDP-CS was as effective as free CDDP in vivo but much less toxic.
Olive Oil/Pluronic Oleogels for Skin Delivery of Quercetin: In Vitro Characterization and Ex Vivo Skin Permeability
Authors: Elmowafy Mohammed , Musa Arafa , Alnusaire Taghreed S. , Shalaby Khaled , Fouda Maged M. A. , Salama Ayman , Al-Sanea Mohammad M. , Abdelgawad Mohamed A. , Gamal Mohammed , Fouad Shahinaze A.
Published: May 2021

The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5–30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro quercetin release and stability, and were compared with that of Pluronic F127 hydrogel. The selected formulation was characterized for its interaction possibility, ex vivo skin permeation and skin histological changes and safety. The particle sizes ranged from 345.3 ± 5.3 nm to 401.5 ± 2.8 nm, and possessed negative charges. The viscosities of the formulations were found in the range of 6367–4823 cps with inverse proportionality to olive oil percentage while the higher percentages showed higher quercetin release. Percentages of 25% and 30% olive oil showed instability pattern under the conditions of accelerated stability studies. Differential scanning calorimetry verified the existence of quercetin in micellar aggregation and the network in the case of hydrogel and oleogel respectively. Ex vivo skin permeation showed an improved skin permeation of quercetin when 20% olive oil containing oleogel was used. Skin histology after 10 days of application showed stratum corneum disruption and good safety profile. Based on these findings, the proposed oleogel containing 20% olive oil denotes a potential carrier for topical delivery of quercetin.
Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids
Authors: Gang Qin , Wang Rong-Tsu , Wang Jung-Chang
Published: May 2021

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.
Warpage Prediction of RHCM Crystalline Parts Based on Multi-Layers
Authors: Li Jiquan , Bei Jie , Liu Wenyong , Xia Xinxin , Zhou Bida , Peng Xiang , Jiang Shaofei
Published: May 2021

Warpage is a typical defect for injection-molded parts, especially for crystalline parts molded by rapid heat cycle molding (RHCM). In this paper, a prediction method is proposed for predicting the warpage of crystalline parts molded by the RHCM process. Multi-layer models were established to predict warpage with the same thicknesses as the skin-core structures in the molded parts. Warpages were defined as the deformations calculated by the multi-layer models. The deformations were solved using the classical laminated plate theory by Abaqus. A model was introduced to describe the elastic modulus with the influence of temperature and crystallinity. The simulation process was divided into two procedures, before ejection and after ejection. Thermal stresses and thermal strains were simulated, respectively, in the procedure before ejection and after ejection. The prediction results were compared with the experimental results, which showed that the average errors between predicted warpage and average experimental warpage are, respectively, 7.0%, 3.5%, and 4.4% in conventional injection molding (CIM), in RHCM under a 60 °C heating mold (RHCM60), and in RHCM under a 90 °C heating mold (RHCM90).
Spiritual Well-Being of Russian Orthodox and Evangelical Christians: Denominational Features
Authors: Divisenko Konstantin S. , Belov Alexei E. , Divisenko Olga V.
Published: May 2021

Till the early 2000s, the Russian “religious renaissance” caused by the collapse of the USSR had been characterized by the rapid growth of religiosity. However, these spiritual changes had been occurring within the Russian Orthodox church and among Evangelical Christians in different manners. Evangelical communities are still relatively small; however their members are highly devoted to their traditions. Meanwhile, Orthodox religiosity is primarily characterized by the nominal self-identification of believers and relatively low level of religious practices’ intensity. The article presents the study results (2017–2019) of the spiritual well-being of Orthodox and Evangelical Christians and its basic confessional and social determinants. The results demonstrate a strong correlation between the enchurchment level and the spiritual well-being level. The authors place particular emphasis on the role of religious coping that determines subjective well-being. The analysis confirmed that the positive ways of religious coping are determined by the regularity of religious practices and the believers’ social capital. We interpret the peculiarities of Orthodox and Evangelicals’ spiritual well-being in the light of differences between their church life’s arrangements which are defined by the believers’ practical religiosity and social capital.
Spatial and Temporal Variability of Minimum Brightness Temperature at the 6.925 GHz Band of AMSR2 for the Arctic and Antarctic Oceans
Authors: Kwon Young-Joo , Hong Sungwook , Park Jeong-Won , Kim Seung Hee , Kim Jong-Min , Kim Hyun-Cheol
Published: May 2021

The minimum brightness temperature (mBT) of seawater in the polar region is an important parameter in algorithms for determining sea ice concentration or snow depth. To estimate the mBT of seawater at 6.925 GHz for the Arctic and Antarctic Oceans and to find their physical characteristics, we collected brightness temperature and sea ice concentration data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) for eight years from 2012 to 2020. The estimated mBT shows constant annual values, but we found a significant difference in the seasonal variability between the Arctic and Antarctic Oceans. We calculated the mBT with the radiative transfer model parameterized by sea surface temperature (SST), sea surface wind speed (SSW), and integrated water vapor (IWV) and compared them with our observations. The estimated mBT represents the modeled mBT emitted from seawater under conditions of 2–5 m/s SSW and SST below 0 °C, except in the Arctic summer. The exceptional summer mBT in the Arctic Ocean was related to unusually high SST. We found evidence of Arctic amplification in the seasonal variability of Arctic mBT.
Detection of Banana Plants Using Multi-Temporal Multispectral UAV Imagery
Authors: Aeberli Aaron , Johansen Kasper , Robson Andrew , Lamb David W. , Phinn Stuart
Published: May 2021

Unoccupied aerial vehicles (UAVs) have become increasingly commonplace in aiding planning and management decisions in agricultural and horticultural crop production. The ability of UAV-based sensing technologies to provide high spatial (<1 m) and temporal (on-demand) resolution data facilitates monitoring of individual plants over time and can provide essential information about health, yield, and growth in a timely and quantifiable manner. Such applications would be beneficial for cropped banana plants due to their distinctive growth characteristics. Limited studies have employed UAV data for mapping banana crops and to our knowledge only one other investigation features multi-temporal detection of banana crowns. The purpose of this study was to determine the suitability of multiple-date UAV-captured multi-spectral data for the automated detection of individual plants using convolutional neural network (CNN), template matching (TM), and local maximum filter (LMF) methods in a geographic object-based image analysis (GEOBIA) software framework coupled with basic classification refinement. The results indicate that CNN returns the highest plant detection accuracies, with the developed rule set and model providing greater transferability between dates (F-score ranging between 0.93 and 0.85) than TM (0.86–0.74) and LMF (0.86–0.73) approaches. The findings provide a foundation for UAV-based individual banana plant counting and crop monitoring, which may be used for precision agricultural applications to monitor health, estimate yield, and to inform on fertilizer, pesticide, and other input requirements for optimized farm management.
Night-Time Light Remote Sensing Mapping: Construction and Analysis of Ethnic Minority Development Index
Authors: Zhao Fei , Song Lu , Peng Zhiyan , Yang Jianqin , Luan Guize , Chu Chen , Ding Jieyu , Feng Siwen , Jing Yuhang , Xie Zhiqiang
Published: May 2021

Using toponym data, population data, and night-time light data, we visualized the development index of the Yi, Wa, Zhuang, Naxi, Hani, and Dai ethnic groups on ArcGIS as well as the distribution of 25 ethnic minorities in the study area. First, we extracted the toponym data of 25 ethnic minorities in the study area, combined with night-time light data and the population proportion data of each ethnic group, then we obtained the development index of each ethnic group in the study area. We compared the development indexes of the Yi, Wa, Zhuang, Naxi, Hani, and Dai ethnic groups with higher development indexes. The results show that the Yi nationality’s development index was the highest, reaching 28.86 (with two decimal places), and the Dai nationality’s development index was the lowest (15.22). The areas with the highest minority development index were concentrated in the core area of the minority development, and the size varied with the minority’s distance. According to the distribution of ethnic minorities, we found that the Yi ethnic group was distributed in almost the entire study area, while other ethnic minorities had obvious geographical distribution characteristics, and there were multiple ethnic minorities living together. This research is of great significance to the cultural protection of ethnic minorities, the development of ethnic minorities, and the remote sensing mapping of lights at night.
Evaluation of Object-Based Greenhouse Mapping Using WorldView-3 VNIR and SWIR Data: A Case Study from Almería (Spain)
Authors: Aguilar Manuel A. , Jiménez-Lao Rafael , Aguilar Fernando J.
Published: May 2021

Plastic covered greenhouse (PCG) mapping via remote sensing has received a great deal of attention over the past decades. The WorldView-3 (WV3) satellite is a very high resolution (VHR) sensor with eight multispectral bands in the visible and near-infrared (VNIR) spectral range, and eight additional bands in the short-wave infrared (SWIR) region. A few studies have already established the importance of indices based on some of these SWIR bands to detect urban plastic materials and hydrocarbons which are also related to plastics. This paper aims to investigate the capability of WV3 (VNIR and SWIR) for direct PCG detection following an object-based image analysis (OBIA) approach. Three strategies were carried out: (i) using object features only derived from VNIR bands (VNIR); (ii) object features only derived from SWIR bands (SWIR), and (iii) object features derived from both VNIR and SWIR bands (All Features). The results showed that the majority of predictive power was attributed to SWIR indices, especially to the Normalized Difference Plastic Index (NDPI). Overall, accuracy values of 90.85%, 96.79% and 97.38% were attained for VNIR, SWIR and All Features strategies, respectively. The main PCG misclassification problem was related to the agricultural practice of greenhouse whitewash (greenhouse shading) that temporally masked the spectral signature of the plastic film.
Terrain Slope Effect on Forest Height and Wood Volume Estimation from GEDI Data
Authors: Fayad Ibrahim , Baghdadi Nicolas , Alcarde Alvares Clayton , Stape Jose Luiz , Bailly Jean Stéphane , Scolforo Henrique Ferraço , Cegatta Italo Ramos , Zribi Mehrez , Le Maire Guerric
Published: May 2021

The Global Ecosystem Dynamics Investigation LiDAR (GEDI) is a new full waveform (FW) based LiDAR system that presents a new opportunity for the observation of forest structures globally. The backscattered GEDI signals, as all FW systems, are distorted by topographic conditions within their footprint, leading to uncertainties on the measured forest variables. In this study, we explore how well several approaches based on waveform metrics and ancillary digital elevation model (DEM) data perform on the estimation of stand dominant heights (Hdom) and wood volume (V) across different sites of Eucalyptus plantations with varying terrain slopes. In total, five models were assessed on their ability to estimate Hdom and four models for V. Results showed that the models using the GEDI metrics, such as the height at different energy quantiles with terrain data from the shuttle radar topography mission’s (SRTM) digital elevation model (DEM) were still dependent on the topographic slope. For Hdom, an RMSE increase of 14% was observed for data acquired over slopes higher than 20% in comparison to slopes between 10 and 20%. For V, a 74% increase in RMSE was reported between GEDI data acquired over slopes between 0–10% and those acquired over slopes higher than 10%. Next, a model relying on the height at different energy quantiles of the entire waveform (HTn) and the height at different energy quartiles of the bare ground waveform (HGn) was assessed. Two sets of the HGn metrics were generated, the first one was obtained using a simulated waveform representing the echo from a bare ground, while the second one relied on the actual ground return from the waveform by means of Gaussian fitting. Results showed that both the simulated and fitted models provide the most accurate estimates of Hdom and V for all slope ranges. The simulation-based model showed an RMSE that ranged between 1.39 and 1.66 m (between 26.76 and 39.26 m3·ha−1 for V) while the fitting-based method showed an RMSE that ranged between 1.26 and 1.34 m (between 26.78 and 36.29 m3·ha−1 for V). Moreover, the dependency of the GEDI metrics on slopes was greatly reduced using the two sets of metrics. As a conclusion, the effect of slopes on the 25-m GEDI footprints is rather low as the estimation on canopy heights from uncorrected waveforms degraded by a maximum of 1 m for slopes between 20 and 45%. Concerning the wood volume estimation, the effect of slopes was more pronounced, and a degradation on the accuracy (increased RMSE) of a maximum of 20 m3·ha−1 was observed for slopes between 20 and 45%.
UAVs for Vegetation Monitoring: Overview and Recent Scientific Contributions
Authors: de Castro Ana I. , Shi Yeyin , Maja Joe Mari , Peña Jose M.
Published: May 2021

This paper reviewed a set of twenty-one original and innovative papers included in a special issue on UAVs for vegetation monitoring, which proposed new methods and techniques applied to diverse agricultural and forestry scenarios. Three general categories were considered: (1) sensors and vegetation indices used, (2) technological goals pursued, and (3) agroforestry applications. Some investigations focused on issues related to UAV flight operations, spatial resolution requirements, and computation and data analytics, while others studied the ability of UAVs for characterizing relevant vegetation features (mainly canopy cover and crop height) or for detecting different plant/crop stressors, such as nutrient content/deficiencies, water needs, weeds, and diseases. The general goal was proposing UAV-based technological solutions for a better use of agricultural and forestry resources and more efficient production with relevant economic and environmental benefits.
Temporal Vegetation Indices and Plant Height from Remotely Sensed Imagery Can Predict Grain Yield and Flowering Time Breeding Value in Maize via Machine Learning Regression
Authors: Adak Alper , Murray Seth C , Božinović Sofija , Lindsey Regan , Nakasagga Shakirah , Chatterjee Sumantra , Anderson Steven L. , Wilde Scott
Published: May 2021

Unoccupied aerial system (UAS; i.e., drone equipped with sensors) field-based high-throughput phenotyping (HTP) platforms are used to collect high quality images of plant nurseries to screen genetic materials (e.g., hybrids and inbreds) throughout plant growth at relatively low cost. In this study, a set of 100 advanced breeding maize (Zea mays L.) hybrids were planted at optimal (OHOT trial) and delayed planting dates (DHOT trial). Twelve UAS surveys were conducted over the trials throughout the growing season. Fifteen vegetative indices (VIs) and the 99th percentile canopy height measurement (CHMs) were extracted from processed UAS imagery (orthomosaics and point clouds) which were used to predict plot-level grain yield, days to anthesis (DTA), and silking (DTS). A novel statistical approach utilizing a nested design was fit to predict temporal best linear unbiased predictors (TBLUP) for the combined temporal UAS data. Our results demonstrated machine learning-based regressions (ridge, lasso, and elastic net) had from 4- to 9-fold increases in the prediction accuracies and from 13- to 73-fold reductions in root mean squared error (RMSE) compared to classical linear regression in prediction of grain yield or flowering time. Ridge regression performed best in predicting grain yield (prediction accuracy = ~0.6), while lasso and elastic net regressions performed best in predicting DTA and DTS (prediction accuracy = ~0.8) consistently in both trials. We demonstrated that predictor variable importance descended towards the terminal stages of growth, signifying the importance of phenotype collection beyond classical terminal growth stages. This study is among the first to demonstrate an ability to predict yield in elite hybrid maize breeding trials using temporal UAS image-based phenotypes and supports the potential benefit of phenomic selection approaches in estimating breeding values before harvest.
Analysis of Groundwater Depletion/Inflation and Freeze–Thaw Cycles in the Northern Urumqi Region with the SBAS Technique and an Adjusted Network of Interferograms
Authors: Wang Baohang , Zhang Qin , Pepe Antonio , Mastro Pietro , Zhao Chaoying , Lu Zhong , Zhu Wu , Yang Chengsheng , Zhang Jing
Published: May 2021

This work investigated the large-scale ground deformations threatening the Northern Urumqi district, China, which are connected to groundwater exploitation and the seasonal freeze–thaw cycles that characterize this frozen region. Ground deformations can be well captured by satellite data using a multi-temporal interferometric synthetic aperture radar (Mt-InSAR) approach. The accuracy of the achievable ground deformation products (e.g., mean displacement time series and related ground displacement time series) critically depends on the number and quality of the selected interferograms. This paper presents a straightforward interferogram selection algorithm that can be applied to identify an optimal network of small baseline (SB) interferograms. The selected SB interferograms are then used to produce ground deformation products using the well-known small baseline subset (SBAS) Mt-InSAR algorithm. The developed interferogram selection algorithm (ISA) permits the selection of the group of SB data pairs that minimize the relative error of the mean ground deformation velocity. Experiments were carried out using a group of 102 Sentinel-1B SAR data collected from 12 April 2017 to 29 October 2020. This research study shows that the investigated farmland region is characterized by a maximum ground deformation rate of about 120 mm/year. Periodic groundwater overexploitation, coupled with irrigation and freeze–thaw phases, is also responsible for seasonal (one-year) ground displacement signals, with oscillation amplitudes up to 120 mm in the zones of maximum displacement.
Alternative Approach for Tsunami Early Warning Indicated by Gravity Wave Effects on Ionosphere
Authors: Foroodi Zahra , Alizadeh Mahdi , Schuh Harald , Tsai Lung-Chih
Published: May 2021

The rapid displacement of the ocean floor during large ocean earthquakes or volcanic eruptions causes the propagation of tsunami waves on the surface of the ocean, and consequently internal gravity waves (IGWs) in the atmosphere. IGWs pierce through the troposphere and into the ionospheric layer. In addition to transferring energy to the ionosphere, they cause significant variations in ionospheric parameters, so they have considerable effects on the propagation of radio waves through this dispersive medium. In this study, double-frequency measurements of the Global Positioning System (GPS) and ionosonde data were used to determine the ionospheric disturbances and irregularities in response to the tsunami induced by the 2011 Tohoku earthquake. The critical frequency of the F2 layer (foF2) data obtained from the ionosonde data also showed clear disturbances that were consistent with the GPS observations. IGWs and tsunami waves have similar propagation properties, and IGWs were detected about 25 min faster than tsunami waves in GPS ground stations at the United States west coast, located about 7900 km away from the tsunami’s epicenter. As IGWs have a high vertical propagation velocity, and propagate obliquely into the atmosphere, IGWs can also be used for tsunami early warning. To further investigate the spatial variation in ionospheric electron density (IED), ionospheric profiles from FORMOSAT-3/COSMIC (F3/C) satellites were investigated for both reference and observation periods. During the tsunami, the reduction in IED started from 200 km and continued up to 272 km altitude. The minimum observed reduction was 2.68 × 105 el/cm3, which has happened at 222 km altitude. The IED increased up to 767 km altitude continuously, such that the maximum increase was 3.77 × 105 el/cm3 at 355 km altitude.
Modelling Spatial Heterogeneity in the Effects of Natural and Socioeconomic Factors, and Their Interactions, on Atmospheric PM2.5 Concentrations in China from 2000–2015
Authors: Wu Tao , Zhou Lixia , Jiang Guojun , Meadows Michael E. , Zhang Jianzhen , Pu Lijie , Wu Chaofan , Xie Xuefeng
Published: May 2021

In recent years, atmospheric PM2.5 pollution in China has become increasingly severe and exploring the relationships among its influencing factors is important in the prevention and control of air pollution. Although previous studies have identified complexity in variations in PM2.5 concentrations and recognized the interaction of multiple factors, little quantitative information is available on the evolution of the relationships among these factors, their spatial heterogeneity, and the multiscale interactions between them. In this study, geographical detector and multiscale geographically weighted regression models have been used to explore the multiscale interactions among natural and socioeconomic factors and PM2.5 concentration in China over the period 2000–2015. The results indicate that the relationship between natural factors and PM2.5 concentration is stronger than that for socioeconomic factors. The type of interaction between each factor is dominated by bivariate and nonlinear enhancement, exhibiting strong interactions between natural factors and anthropogenic factors. Although the effect of each factor on PM2.5 is complex, the relative influence of both human activities and social factors is shown to have gradually increased over time and population, agriculture, urbanization, and socioeconomic activities in general make important contributions to PM2.5. In addition, the scale of effects related to natural factors is smaller and more stable compared to the influence of human activities during the period 2000-2015. There are significant differences in the way natural factors and socioeconomic factors affect PM2.5, and there is strong non-stationarity of spatial relationships. Factors associated with topography, vegetation (NDVI), climate (temperature), natural sources, and agricultural activity are shown to be important determinants of PM2.5 across China and warrant significant attention in terms of managing atmospheric pollution. The study demonstrates that spatial differences in the direction, intensity, and scale of each factor should be accounted for to improve prevention and control measures and alleviate regional PM2.5 pollution.
Instantaneous Self-Powered Sensing System Based on Planar-Structured Rotary Triboelectric Nanogenerator
Authors: Kuang Shuangyang , Suo Xiaochen , Song Peiyi , Luo Jianjun
Published: May 2021

Self-powering electronics by harvesting mechanical energy has been widely studied, but most self-powering processes require a long time in the energy harvesting procedure, resulting in low efficiency or even system failure in some specific applications such as instantaneous sensor signal acquisition and transmission. In order to achieve efficient self-powered sensing, we design and construct an instantaneous self-powered sensing system, which puts heavy requirements on generator’s power and power management circuit. Theoretical analysis and experimental results over two types of generators prove that the planar-structured rotary triboelectric nanogenerator possesses many advantages over electromagnetic generator for the circumstances of instantaneous self-powering. In addition, an instantaneous driving mode power management circuit is also introduced showing advanced performance for the instantaneous self-powering sensing system. As a proof-of-concept, an integrated instantaneous self-powered sensing system is demonstrated based on Radio-Frequency transmission. This work demonstrates the potential of instantaneous self-powered sensing systems to be used in a wide range of applications such as smart home, environment monitoring, and security surveillance.
Extraction of the Structural Properties of Skin Tissue via Diffuse Reflectance Spectroscopy: An Inverse Methodology
Authors: Chen Bin , Zhang Yong , Gao Shang , Li Dong
Published: May 2021

For the laser treatment of vascular dermatosis, the blood vessel morphology and depth in skin tissue is essential to achieve personalized intelligent therapy. The morphology can be obtained from the laser speckle imaging, and vessel depth was extracted by an inverse methodology based on diffuse reflectance spectrum. With optimized spot size of 0.5 mm and known optical properties, the proposed method was experimentally validated via the spectral measurement of microcapillary with known size and depth embedded in an epoxy resin-based skin phantom. Results prove that vessel depth can be extracted with an average relative error of 5%, thereby providing the foundation for a personalized, precise, and intelligent laser treatment of vascular dermatosis.
Metrological Evaluation of Human–Robot Collaborative Environments Based on Optical Motion Capture Systems
Authors: González Leticia , Álvarez Juan C. , López Antonio M. , Álvarez Diego
Published: May 2021

In the context of human–robot collaborative shared environments, there has been an increase in the use of optical motion capture (OMC) systems for human motion tracking. The accuracy and precision of OMC technology need to be assessed in order to ensure safe human–robot interactions, but the accuracy specifications provided by manufacturers are easily influenced by various factors affecting the measurements. This article describes a new methodology for the metrological evaluation of a human–robot collaborative environment based on optical motion capture (OMC) systems. Inspired by the ASTM E3064 test guide, and taking advantage of an existing industrial robot in the production cell, the system is evaluated for mean error, error spread, and repeatability. A detailed statistical study of the error distribution across the capture area is carried out, supported by a Mann–Whitney U-test for median comparisons. Based on the results, optimal capture areas for the use of the capture system are suggested. The results of the proposed method show that the metrological characteristics obtained are compatible and comparable in quality to other methods that do not require the intervention of an industrial robot.