Search

In this paper, by using the Riccati transformation and integral inequality technique, we establish several oscillation criteria for second-order Emden–Fowler neutral delay differential equations under the canonical case and non-canonical case, respectively. Compared with some recent results reported in the literature, we extend the range of the neutral coefficient. Therefore, our results generalize to some of the results presented in the literature. Furthermore, several examples are provided to illustrate our conclusions. [ABSTRACT FROM AUTHOR]

The development of heterogeneous Fenton catalysts with good performance and stability is a challenge in the field of wastewater treatment. In this work, MgAlFe hydrotalcite-like compounds (MgAlFe-HTLcs) were prepared by solid phase reaction at room temperature and modified via a hydrothermal process. The experimental results showed that MgAlFe-HTLcs had a good layered structure with the same proportion of iron and aluminium, 18 h of crystallisation time and 110°C of crystallisation temperature and the lamellar structure was more uniform by solid grinding. Furthermore, the addition of iron can activate H2O2 more effectively to generate active oxygen which is •OH. The degradation experiments demonstrated that nearly 99.0% degradation efficiency was achieved for 10 mg/L Malachite Green (MG) solution within 60 min at the conditions of 0.10 g·L−1 MgAlFe-HTLcs, 0.10 mol·L-1 H2O2 and a natural pH of 6.3. Total organic carbon (TOC) removal reached 72.2% in a 70 min reaction. BET and XRD were measured to further discuss the stability and durability. Finally, a possible mechanism for the degradation of MG was presumed. [ABSTRACT FROM AUTHOR]

Background: Monopterusalbus is a hermaphroditic fish with sex reversal from ovaries to testes via the ovotestes in the process of gonadal development, but the molecular mechanism of the sex reversal was unknown. Methods: We produced transcriptomes containing mRNAs and lncRNAs in the crucial stages of the gonad, including the ovary, ovotestis and testis. The expression of the crucial lncRNAs and their target genes was detected using qRT‒PCR and in situ hybridization. The methylation level and activity of the lncRNA promoter were analysed by applying bisulfite sequencing PCR and dual-luciferase reporter assays, respectively. Results: This effort revealed that gonadal development was a dynamic expression change. Regulatory networks of lncRNAs and their target genes were constructed through integrated analysis of lncRNA and mRNA data. The expression and DNA methylation of the lncRNAs MSTRG.38036 and MSTRG.12998 and their target genes Psmβ8 and Ptk2β were detected in developing gonads and sex reversal gonads. The results showed that lncRNAs and their target genes exhibited consistent expression profiles and that the DNA methylation levels were negatively regulated lncRNA expression. Furthermore, we found that Ptk2β probably regulates cyp19a1 expression via the Ptk2β/EGFR/STAT3 pathway to reprogram sex differentiation. Conclusions: This study provides novel insight from lncRNA to explore the potential molecular mechanism by which DNA methylation regulates lncRNA expression to facilitate target gene transcription to reprogram sex differentiation in M.albus, which will also enrich the sex differentiation mechanism of teleosts. Highlights: Construction of the lncRNA-mRNA interaction network in the sex differentiation. DNA methylation was negatively associated with lncRNA expression in developing gonads. Ptk2β regulate Ptk2β/EGFR/STAT3 pathway to potentially regulate sex differentiation. Plain language summary: Monopterusalbus is a hermaphroditic fish that undergoes sex reversal from female to male via intersex during the process of the gonadal differentiation which was an ideal model for epigenetic modification research. After laying eggs, the female M.albus reversal to the intersex. So that the female have a shorter stage and smaller body size which cause low egg production. In the present study, we produced the transcriptomes which contain mRNA and lncRNA in the crucial stage of the gonad including ovary, ovotestis and testis. This effort reveals that gonadal development was a dynamic expression changes. Regulatory networks of lncRNAs and its target genes were constructed though integrated analysis of lncRNA and mRNA data. We found DNA methylation was negatively associated with lncRNA (MSTRG.38036 and MSTRG.12998) expression in developing gonads. Additionally, 17α-methyltestosterone inhibit the expression of lncRNA and increase methylation. Furthermore, we found that Ptk2β probably regulates cyp19a1 expression via the Ptk2β/EGFR/STAT3 pathway to reprogram sex differentiation. The present study on the gonadal differentiation of M.albus provides novel insights from lncRNA to explore potential molecular mechanism. In the future, function of the lncRNA will be further studied and the gene editing technology will be applied to cultivate the female with high fecundity to improve the yield of fish fry. [ABSTRACT FROM AUTHOR]

It is an urgent need that defect repair can develop from simple device fixation to living tissue reconstruction, from short life function replacement to permanent regeneration repair. At present, bone transplantation has become the second largest transplantation surgery after blood transfusion, and artificial bone transplantation generates great hope for the repair and treatment of bone defect. In order to repair bone defect, artificial bone must have good biological properties and sufficient mechanical properties, and it should also have the shape matching to bone defect site and the connected porous structure. For structures and properties requirements of artificial bone, in this review three major challenges faced by artificial bone transplantation are systemtically analyzed and current methods and strategies to address these issues are discussed: 1) the need for developing a type of bone scaffold material with both biological and mechanical properties, 2) the need for realizing the controllable fabrication of individual shape and multistage pore structure of bone scaffold, 3) the need for realizing the transformation from man‐made structure to biological structure. Besides, it summarizes the advantages and disadvantages of these methods and discusses the potential future directions of structural and functional adaptive artificial bone for bone defect regeneration. [ABSTRACT FROM AUTHOR]

The swamp eel, Monopterus albus, is an important aquaculture species in Asia (mainly China) whose production has seriously suffered from infectious diseases. In spite of the critical requirement for aquaculture practices, to date there is scant information on its immune defence. Here, the genetic characteristics of Toll‐like receptor 9 (TLR9), which plays crucial roles in the initiation of host defence against microbial invasion, were analysed. It exhibits a striking lack of genetic variation resulting from a recent demographic bottleneck. A comparison with the homologue of M. javanensis revealed that replacement but not silent differences have nonrandomly accumulated in the coding sequences at the early stage following their split from a common ancestor. Furthermore, the replacements relevant to the type II functional divergence have mainly occurred in structural motifs mediating ligand recognition and receptor homodimerization. These results provide hints to understand the diversity‐based strategy of TLR9 in the arms race against pathogens. Furthermore, the findings reported here give credence to the importance of basic immunology knowledge, especially for the key elements, in genetic engineering and breeding for disease resistance in the eel and other fishes. [ABSTRACT FROM AUTHOR]

Promoting the activity of catalyst, achieving high CO2 conversion and increasing light olefins yield are important in CO2 hydrogenation to olefin. Herein, SiO2 was doped in CuO‐ZnO‐ZrO2 to form multi‐oxides of CuO‐ZnO‐ZrO2‐SiO2 by co‐precipitation method, and the multi‐oxides was mixed with SAPO‐34 molecular sieves mechanically to form a composite catalyst of CuO‐ZnO‐ZrO2‐SiO2/SAPO‐34. Compared with CuO‐ZnO‐ZrO2, doping of SiO2 increases the dispersion and thermal stability of metal oxides, provides more sites for CO2 activated, and delays the aggregation of metal particles at higher temperature. Doped SiO2 can also adsorb the water from hydrogenation process to improve the olefins yield and hinder the formation of CO from reverse water gas shift. Thus, under the condition of reaction temperature at 420 °C, pressure of 3.0 MPa, space velocity of 1800 mL gcat−1 h−1, CO2/H2 (molar ratio) of 1 : 3 and the mass ratio of CuO‐ZnO‐ZrO2‐SiO2 (containing 8 % SiO2) to SAPO‐34 of 1 : 1, the direct CO2 hydrogenation to light olefins on CuO‐ZnO‐ZrO2‐SiO2/SAPO‐34 shows that the conversion of CO2 is 53.9 % and the selectivity of light olefins is 52.9 %, while the CO selectivity is only 13.6 %. [ABSTRACT FROM AUTHOR]

Background: Monopterus albus is a hermaphroditic and economically farmed fish that undergoes sex reversal from ovary to testis via ovotestis during gonadal development. The epigenetic changes that are associated with gonadal development in this species remain unclear. Methods: We produced DNA methylome, transcriptome, and chromatin accessibility maps of the key stages of gonad development: ovary, ovotestis, and testis. The expression of the key candidate genes was detected using qRT-PCR and in situ hybridization and the methylation levels were analysed using bisulphite sequencing PCR. Promoter activity and regulation were assessed using dual-luciferase reporter assays. Results: Gonadal development exhibits highly dynamic transcriptomic, DNA methylation, and chromatin accessibility changes. We found that DNA methylation status, especially of the transcription start site, was significantly negatively correlated with gene expression while chromatin accessibility exhibited no correlation with gene expression during gonadal development. The epigenetic signatures revealed many novel regulatory elements and genes involved in sex reversal, which were validated. DNA methylation detection and site mutation of plastin-2 promoter, as a candidate gene, revealed that DNA methylation could impact the binding of transcription factor dmrt1 and foxl2 through methylation and demethylation to regulate plastin-2 expression during gonadal development. Conclusions: These data provide novel insights into epigenetic modification and help elucidate the potential molecular mechanism by which dynamic modification of DNA methylation plays a crucial role in gonadal development. Highlights: DNA methylation modification plays a more crucial role than chromatin accessibility in gonad development. DNA methylation in the transcription start site plays a key role in gonad development. DNA methylation of the plastin-2 promoter inhibited gene expression. Plastin-2 is positively regulated by dmrt1 while negatively regulated by foxl2. [ABSTRACT FROM AUTHOR]

Nanosheet-liked mesoporous SAPO-34 zeolites were synthesized by a facile surfactant-assisted hydrothermal synthesis method. Compositions, morphology, acidities, chemical environment and texture properties of SAPO-34 zeolites synthesized were characterized by XRD, SEM, TEM, AFM, NH3-TPD, N2 adsorption–desorption, XPS, and TG measurements. The morphology and the surface acid density of SAPO-34 zeolite can be controlled by adding of cetyltrimethylammonium bromide (CTAB) and using triethanolamine (TEA) as the template. The nanosheet-liked mesoporous SAPO-34 zeolites have lower amount of strong acid strongth with the thickness of about 3.0 nm. The catalysis performance for methanol-to-olefin (MTO) over nanosheet-like SAPO-34 zeolites was systematically studied. Under the condition of temperature at 400 °C, feeding WHSV of 2.0 h−1, catalyst mass of 0.2 g and at atmospheric pressure, the methanol conversion is nearly 100% and the light olefins selectivity is 97.35%. As nanosheet-like SAPO-34 zeolites shorten the diffusion path and enhance the mass flow to and away from the catalytic centers, the catalyst lifetime is more than 420 min. [ABSTRACT FROM AUTHOR]

Let K be a field of characteristic zero. It is proved that images of linear K-derivations and linear K- E -derivations of the algebra K [ x , y , z ] of polynomials in three variables over K are Mathieu-Zhao subspaces, which affirms the corresponding LFED conjecture. [ABSTRACT FROM AUTHOR]

Accurate and reliable land cover information is vital for ecosystem management and regional sustainable development, especially for ecologically vulnerable areas. The South China Karst, one of the largest and most concentrated karst distribution areas globally, has been undergoing large-scale afforestation projects to combat accelerating land degradation since the turn of the new millennium. Here, we assess five recent and widely used global land cover datasets (i.e., CCI-LC, MCD12Q1, GlobeLand30, GlobCover, and CGLS-LC) for their comparative performances in land dynamics monitoring in the South China Karst during 2000–2020 based on the reference China Land Use/Cover Database. The assessment proceeded from three aspects: areal comparison, spatial agreement, and accuracy metrics. Moreover, divergent responses of overall accuracy with regard to varying terrain and geomorphic conditions have also been quantified. The results reveal that obvious discrepancies exist amongst land cover maps in both area and spatial patterns. The spatial agreement remains low in the Yunnan–Guizhou Plateau and heterogeneous mountainous karst areas. Furthermore, the overall accuracy of the five datasets ranges from 40.3% to 52.0%. The CGLS-LC dataset, with the highest accuracy, is the most accurate dataset for mountainous southern China, followed by GlobeLand30 (51.4%), CCI-LC (50.0%), MCD12Q1 (41.4%), and GlobCover (40.3%). Despite the low overall accuracy, MCD12Q1 has the best accuracy in areas with an elevation above 1200 m or a slope greater than 25°. With regard to geomorphic types, accuracy in non-karst areas is evidently higher than in karst areas. Additionally, dataset accuracy declines significantly (p < 0.05) with an increase in landscape heterogeneity in the region. These findings provide useful guidelines for future land cover mapping and dataset fusion. [ABSTRACT FROM AUTHOR]

Cadmium-modified HZSM-5 zeolite (Cd/HZSM-5) was prepared by ultrasound-assisted impregnation and its catalytic performance for methanol to aromatics (MTA) was investigated. It was characterized by means of XRD, SEM, TEM, Py-IR, N2 adsorption/desorption, NH3-TPD and XPS. Cd species distribute in the surface of the HZSM-5 zeolite, decreasing the crystallinity and increasing the Lewis acidity strength. Under the operating reaction condition of temperature at 400 °C, pressure at 0.1 MPa and space velocity of 1.896 h−1, 1.4 wt% Cd/HZSM-5 zeolites showed good catalytic activity for MTA with the aromatic's selectivity of 71.1%. Compared with that of about 7.5% over HZSM-5, the trimethylbenzene isomers in aromatics is 86.6% and the main product is 1,2,4-trimethylbenzene with selectivity of 34.0% in all products and 86.5% in trimethylbenzene isomers over 1.4 wt% Cd/HZSM-5 zeolites. [ABSTRACT FROM AUTHOR]

Waste residue of Chinese prickly ash seeds were simply treated with aqueous ZnCl2 to prepared the high-performed activated carbon. It was characterized by the methods of XRD, SEM, EDX, FT-IR, BET and XPS. The synergetic adsorption performance of Chinese prickly ash seeds activated carbon for Pb2+, Ni2+ and Acid Orange IΙ (AO) was studied. In the single-component system, the adsorption capacity of Pb2+, Ni2+ and AO were 15.1, 10.7 and 188.4 mg/g, respectively. In the AO-Pb2+ system, the maximum adsorption capacity of Pb2+ and AO were 79.40 and 332.68 mg/g under temperature of 30°C and pH of 5.0, respectively. For AO-Ni2+ system, it was 375.6 and 38.3 mg/g, respectively. The adsorption kinetics was satisfactorily fitted by the pseudo-second-order model. The synergic adsorption process can be smoothly described by the non-modified Sips isotherm. [ABSTRACT FROM AUTHOR]

A series of hydrogels were successfully prepared with low grade palygorskite and hydroxypropyl methyl cellulose as raw materials by free radical graft copolymerization method. The morphology, functional groups, crystalline phases and thermal stability of the hydrogels were characterized by SEM, FT‐IR, XRD and TG, respectively. The adsorption properties of hydrogels were tested. The water absorption rate of hydrogel with Jiangsu Xu Yu palygorskite (PGSH), Gansu Linze white grey palygorskite (WPGSH) and Gansu Linze red palygorskite (RPGSH) as raw materials was 1332 g/g, 1204 g/g and 1146 g/g, respectively. The three hydrogels showed excellent adsorption capacity for 100 mg/L methylene blue solution at room temperature, and the maximum adsorption capacities of PGSH, WPGSH and RPGSH were 236.44 mg/g, 227.72 mg/g and 223.01 mg/g, respectively. The adsorption kinetics of methylene blue over hydrogels was a pseudo two stage kinetic equation. [ABSTRACT FROM AUTHOR]

In this study, a new fluorinated methacrylamide (MACF) was synthesized and evaluated as an adsorbent in the dispersive solid‐phase extraction for the effective determination and extraction of 20 organophosphorus pesticides (OPPs) from ginseng samples using the QuEChERS (quick, easy, cheap, effective, rugged, safe) method coupled with GC–MS/MS. The properties of MACF were characterized using Fourier‐transform infrared spectroscopy, elemental analysis, and high‐resolution 19F NMR. MACF, chitosan, primary and secondary amine, octadecylsilane, graphitized carbon black, Z‐Sep, Z‐Sep+, and EMR‐Lipid were compared in terms of extraction efficiency. The best results were obtained when MACF was used. Matrix‐matched calibration was employed for quantification. All the OPPs exhibited good linearity (r2 > 0.9969) with the concentration at their respective concentration ranges. The limits of detection were 1.5–3.0 μg/kg, and the limits of quantification were 5.0–10.0 μg/kg. The trueness of the 20 pesticides at four spiked levels ranged from 86.1 to 111.1%, and the relative standard deviation was less than 11.3%. The modified QuEChERS method using MACF as the adsorbent was sensitive, reliable, and cost‐effective and could be used for the determination of 20 OPP residues in ginseng. [ABSTRACT FROM AUTHOR]

Propane dehydrogenation to propene is an endothermic reaction and CO2 hydrogenation to light olefins is an exothermic reaction. Using the CO2 hydrogenation reaction to consume the hydrogen from the propane dehydrogenation reaction, which is more favorable to propylene formation. A new method for coupling propane and CO2 to propylene is presented. The V–Fe modified KIT-6 was prepared by the ultrasonic-assisted impregnation method and used for coupling reaction of propane with CO2 to propylene. Exploring the relationship between catalytic properties and physicochemical characteristics through several characterization methods. As the appropriate amounts of V and Fe species were introduced into the framework of KIT-6, V–Fe modified KIT-6 performed large specific surface area, a highly ordered mesoporous structure and highly dispersed V and Fe active sites. The catalysis performance of V–Fe modified KIT-6 zeolites for production of propylene by propane dehydrogenation, CO2 hydrogenation and coupling reaction of C3H8 with CO2 was compared. Under the conditions of C3H8/CO2/N2 = 1:4:5, total flow rate = 20 mL/min, the temperature at 580 °C, the reaction pressure at 0.1 MPa, V/Fe molar ratio = 2 and the catalyst mass of 0.2 g, the propane conversion, propylene selectivity and yield are 37.8%, 87.0% and 32.9%, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemistry is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The accurate and timely mapping of summer maize is vital for agricultural management and food security. Time-series remotely sensed imagery provides a promising data resource for crop mapping by characterizing growth cycles over time. Therefore, this study explores summer maize mapping with composited time-series Sentinel-1A imagery of a typical crop field in China. First, time-series backscattering coefficients of major land-cover types (i.e. summer maize, peanut, forest, settlements, and water) are extracted from multi-temporal Sentinel-1A imagery. Second, according to the growth cycles of summer maize and peanut, the multi-temporal Sentinel-1A images are composited to enhance the characteristics of the summer maize growth cycle, while also eliminating redundant information and differences in phenology. Third, the decision-tree method is used to perform pixel-level classification; samples with an area of 1 km2 are collected as validation datasets. The results show that Sentinel-1A VH-polarized images are more sensitive to the summer maize growth cycle than VV-polarized images. The summer maize cropping areas are estimated with an overall accuracy of 96.55% and a kappa coefficient of 0.93. The results suggest that multi-temporal Sentinel-1A imagery is capable of characterizing the growth cycle of summer maize, and provides a promising solution for accurate summer maize mapping, irrespective of weather conditions. [ABSTRACT FROM AUTHOR]

Nanoscale polymer spherical and hollow structure HZSM-5 zeolites are prepared by hydrothermal and desilication–recrystallization methods. In addition, the crystallite size of two types of HZSM-5 can be easily controlled by changing H2O/Si mole ratio. The hollow structure HZSM-5 zeolite is formed, it is due to the 010 crystal plane is the most energetically favorable orientation in silicalite-1 and the Si species is first removed on this crystal plane. The properties of different morphology zeolites were characterized by means of XRD, SEM, TEM, NH3-TPD, N2 isothermal adsorption–desorption and TG, and the catalytic performance of these two types of HZSM-5 in MTA reaction was investigated in a fixed-bed differential reactor. The results showed that the multilevel pore structure and suitable acid strength and more acid density were obtained in the hollow structure HZSM-5 zeolite. Therefore, the hollow HZSM-5 zeolite exhibited that higher catalytic lifetime and selectivity of aromatics than nanoscale polymer spherical HZSM-5 zeolite in MTA reaction. Furthermore, the Al distribution on the 010 crystal plane may change slightly during the process of fabricating hollow mesoporous, which leads to higher selectivity of p-xylene over hollow HZSM-5 than nanoscale polymer spherical HZSM-5 zeolite. [ABSTRACT FROM AUTHOR]

To understand the relationship between the catalytic performance, crystallite size, and acidity of SAPO-34 zeolites better, a series of SAPO-34 zeolites were prepared by hydrothermal crystallization using palygorskite as silicon and partial aluminum source, and selecting two kinds of triethylamine, morpholine and tetraethylammonium hydroxide as dual templates. The obtained SAPO-34 zeolites were characterized via the methods of XRD, SEM, N2-adsorption–desorption, NH3-TPD, FTIR, XRF, 29Si MAS NMR, 27Al MAS NMR and TG. The properties of the templates affected the crystal growth rate that triethylamine and morpholine can cause a larger crystallite size while tetraethylammonium hydroxide can form small crystallite size particles. The number of acid sites of SAPO-34 zeolites first decreased and then increased with the increase of morpholine. The formation of Si islands can enhance the number of acid sites of SAPO-34 zeolites. The catalytic performance of SAPO-34 zeolites in methanol-to-olefins (MTO) reaction was investigated in a fixed bed reactor. Under reaction conditions, when the reaction temperature was 400 °C, the feed WHSV was 2.0 h−1, the mass of the catalyst was 0.5 g, at atmospheric pressure, the sample with an amount of acid sites of 0.85 mmol g−1 and crystallite size of 0.84 μm exhibited the optimum catalytic performance with methanol conversion at 100%, light olefin selectivity at 97.15% and catalytic lifetime at more than 1050 min. [ABSTRACT FROM AUTHOR]

S-doped NiFe-based particles were prepared by a solvothermal method and used to degrade methylene blue (MB) aqueous solutions with visible light in a heterogeneous Fenton reaction. The obtained solid samples were characterized by XRD, SEM, TEM, and XPS. It was found that 0.2 g L−1 NiFe2S4 can degrade 99.8% MB solution within 6 min in the presence of 5 mM H2O2 and natural pH. The recycle experiments results indicate that the NiFe2S4 catalyst possessed better stability than NiFe2O4. Furthermore, NiFe2S4 particles can be easily separated from contaminant solution by using a magnet due to their excellent ferromagnetism. COD analysis experiments indicated that the COD removal rate of NiFe2S4 is 73.1% in 30 min. A possible mechanism was proposed, and the degradation products were measured by LC-MS. [ABSTRACT FROM AUTHOR]

To improve the dispersion of metals and to enhance the catalytic performance of SAPO-34 molecular sieves, the template-assisted method was applied to synthesize Co, Ni and Zn modified SAPO-34 molecular sieves by using palygorskite as silicon source and tetraethylammonium hydroxide as template. The metal modified SAPO-34 molecular sieves were characterized by XRD, SEM, XPS, N2-adsorption-desorption, NH3-TPD, FTIR, ICP-AES and TG. The N atoms of tetraethylammonium hydroxide exhibited the different forces to three metal ions, thus the acidity of the molecular sieves was further regulated. Compared with metal modified SAPO-34 molecular sieves prepared by impregnation, metal modified SAPO-34 molecular sieves prepared by template-assisted maintained higher surface area, bigger pore volume and better dispersion of metals. The catalytic performance of metal modified SAPO-34 molecular sieves prepared by template-assisted method in the reaction of methanol-to-olefins (MTO) was investigated in the fixed bed reactor. Under the reaction conditions that the reaction temperature was 400 °C, the reaction pressure was 0.1 MPa, the feed WHSV was 2.0 h−1 and the mass of catalyst was 0.5 g, Ni modified SAPO-34 molecular sieves exhibited great methanol conversion and high selectivity to light olefins. The selectivity of light olefins reached 95.7%. [ABSTRACT FROM AUTHOR]

Over recent decades, Chinese giant salamanders Andrias spp. have declined dramatically across much of their range. Overexploitation and habitat degradation have been widely cited as the cause of these declines. To investigate the relative contribution of each of these factors in driving the declines, we carried out standardized ecological and questionnaire surveys at 98 sites across the range of giant salamanders in China. We did not find any statistically significant differences between water parameters (temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, alkalinity, hardness and flow rate) recorded at sites where giant salamanders were detected by survey teams and/or had been recently seen by local respondents, and sites where they were not detected and/or from which they had recently been extirpated. Additionally, we found direct and indirect evidence that the extraction of giant salamanders from the wild is ongoing, including within protected areas. Our results support the hypothesis that the decline of giant salamanders across China has been primarily driven by overexploitation. Data on water parameters may be informative for the establishment of conservation breeding programmes, an initiative recommended for the conservation of these species. [ABSTRACT FROM AUTHOR]

Background: The Chinese giant salamander Andrias davidianus is an important amphibian species in China because of its increasing economic value, protection status and special evolutionary position from aquatic to terrestrial animal. Its large genome presents challenges to genetic research. Genetic linkage mapping is an important tool for genome assembly and determination of phenotype-related loci. Results: In this study, we constructed a high-density genetic linkage map using ddRAD sequencing technology to obtain SNP genotyping data of members from an full-sib family which sex had been determined. A total of 10,896 markers were grouped and oriented into 30 linkage groups, representing 30 chromosomes of A. davidianus. The genetic length of LGs ranged from 17.61 cM (LG30) to 280.81 cM (LG1), with a mean inter-locus distance ranging from 0.11(LG3) to 0.48 cM (LG26). The total genetic map length was 2643.10 cM with an average inter-locus distance of 0.24 cM. Three sex-related loci and four sex-related markers were found on LG6 and LG23, respectively. Conclusion: We constructed the first High-density genetic linkage map and identified three sex-related loci in the Chinese giant salamander. Current results are expected to be a useful tool for future genomic studies aiming at the marker-assisted breeding of the species. [ABSTRACT FROM AUTHOR]

Early-season crop identification is of great importance for monitoring crop growth and predicting yield for decision makers and private sectors. As one of the largest producers of winter wheat worldwide, China outputs more than 18 % of the global production of winter wheat. However, there are no distribution maps of winter wheat over a large spatial extent with high spatial resolution. In this study, we applied a phenology-based approach to distinguish winter wheat from other crops by comparing the similarity of the seasonal changes of satellite-based vegetation index over all croplands with a standard seasonal change derived from known winter wheat fields. Especially, this study examined the potential of early-season large-area mapping of winter wheat and developed accurate winter wheat maps with 30 m spatial resolution for 3 years (2016–2018) over 11 provinces, which produce more than 98 % of the winter wheat in China. A comprehensive assessment based on survey samples revealed producer's and user's accuracies higher than 89.30 % and 90.59 %, respectively. The estimated winter wheat area exhibited good correlations with the agricultural statistical area data at the municipal and county levels. In addition, the earliest identifiable time of the geographical location of winter wheat was achieved by the end of March, giving a lead time of approximately 3 months before harvest, and the optimal identifiable time of winter wheat was at the end of April with an overall accuracy of 89.88 %. These results are expected to aid in the timely monitoring of crop growth. The 30 m winter wheat maps in China are available via an open-data repository (DOI: 10.6084/m9.figshare.12003990, Dong et al., 2020a). [ABSTRACT FROM AUTHOR]

Early season crop identification is of great importance for monitoring crop growth and predicting yield for decision-makers and private sectors. As one of the largest producers of winter wheat worldwide, China outputs more than 18% of the global production of winter wheat. However, there are no distribution maps of winter wheat over a large spatial extent with high spatial resolution. In this study, we applied a phenology-based approach to distinguish winter wheat from other crops by comparing the similarity of the seasonal changes of satellite-based vegetation index over all croplands with a standard seasonal change derived from known winter wheat fields. Especially, this study examined the potential of early season large-area mapping of winter wheat and developed accurate winter wheat maps with 30 m spatial resolution for three years (2016-2018) over eleven provinces, which produce more than 98 % of the winter wheat in China. A comprehensive assessment based on survey samples revealed producer' and user' accuracies higher than 89.30 % and 90.59 %, respectively. The winter wheat map exhibited good correspondence with the agricultural census area data at the municipal and county levels. In addition, the earliest identifiable time of the geographical location of winter wheat was achieved by the end of March, giving a lead time of approximately three months before harvest, and the optimal identifiable time of winter wheat was at the end of April with an overall accuracy of 89.88 %. These results are expected to aid in the timely monitoring of crop conditions. The 30 m winter wheat maps in China are available via an open-data repository (DOI: http://doi.org/10.6084/m9.figshare.12003990, Dong et al., 2020). [ABSTRACT FROM AUTHOR]

Currently, we lack a clear understanding of how climate influences the responses of soil organic carbon (OC) and nitrogen (N) to land-use changes in semiarid regions. Thus, to clarify the mechanisms involved, we measured the soil OC and total N (TN) concentrations and stocks in the 0–100 cm soil layer in adjacent grassland, farmland, and woodland at five sites on the Loess Plateau in China, which varied in terms of the mean annual precipitation (MAP) and mean annual temperature (MAT). The farmland or woodland was converted from grassland at each site. Conversion of grassland to farmland significantly reduced the soil OC and TN, with greater decreases in sites with relatively lower MAP and MAT (–0.60 Mg OC ha−1 yr−1 and –0.22 Mg TN ha−1 yr−1, respectively) than sites with relatively higher MAP and MAT (–0.35 Mg OC ha−1 yr−1 and –0.04 Mg TN ha−1 yr−1). Conversion of grassland to woodland increased OC and TN at sites with higher MAP and MAT, but decreased them at sites with lower MAP and MAT. OC and TN increased to a depth of 100 cm with MAP and MAT after this land-use change. OC and TN decreased at relatively drier and colder sites, but increased at relatively wetter and warmer sites. These findings provide insights into the effects of land-use changes on the soil OC and TN under different climate conditions, thereby facilitating the sustainable management of grasslands in semiarid regions. [ABSTRACT FROM AUTHOR]

The dehydrogenation of propane to propylene is endothermic reaction will generate hydrogen, while the hydrogenation of CO2 to light olefins is exothermic reaction with hydrogen as reactant. Using the CO2 hydrogenation reaction to consume the hydrogen from the propane dehydrogenation reaction, which is more beneficial to propylene generation. Thus, a promising approach of coupling propane with CO2 to produce propylene was proposed. A simple wetness impregnation method was used to prepare the In/HZSM‐5 composite catalyst for this coupling reaction. It was characterized by means of XRD, SEM, TEM, H2‐TPR, NH3‐TPD, XPS, TG, and N2 isothermal adsorption‐desorption. Effects of indium loading, feed volume ratio of propane to CO2, reaction pressure and temperature on the coupling of propane with CO2 to propylene were investigated in a fixed‐bed reactor. When the mass content of indium is 12%, the feeding volume ratio of propane to CO2 is 1 : 4, the reaction pressure is 0.3 MPa and the reaction temperature is 580 °C, the propylene selectivity is 71.41%, as well as the conversion per pass of propane and CO2 is 17.74% and 5.08%, respectively. [ABSTRACT FROM AUTHOR]

Using ethylene glycol as solvent and PVP as structure-directing agent, CuFe2O4 nanospheres were successfully prepared by solvothermal method. The crystal structure, morphology, magnetic properties, and pore-size distribution of samples were characterized by using X-ray diffraction, scanning electron microscope, transmission electron microscope, VSM, and BET, respectively. The effects of various preparation factors on the crystal form and morphology of the obtained samples were systematically discussed. The result exhibited that the self-assembled hollow nanospheres with good crystal form and morphology are obtained under the conditions of 0.50 g PVP, 9 mmol NaAc, reaction temperature of 180 °C, and reaction time of 24 h. The catalytic activity of CuFe2O4 hollow nanospheres was evaluated by the degradation of methylene blue (MB) and the possible degradation mechanism and pathway of MB in the CuFe2O4/H2O2 photo-Fenton-like system were proposed. In addition, the properties of CuFe2O4 particles prepared by different methods were compared and analyzed. The sample synthesized by solvothermal method has a large specific surface area and excellent magnetic properties. Furthermore, the increase in the photoelectric response and the conductivity are beneficial to the improvement of catalytic performance. [ABSTRACT FROM AUTHOR]

The Chinese giant salamander Andrias davidianus is a protected amphibian with high nutritional and economic value. Understanding its sex determination mechanism is important for improving culture techniques and sex control in breeding. However, little information on the characterization of critical genes involved in sex is available. Herein, sequencing of ovary and test produced 40,783,222 and 46,128,902 raw reads, respectively, which were jointly assembled into 80,497 unigenes. Of these, 36,609 unigenes were annotated, of which 8907 were female-biased and 10,385 were male-biased. Several sex-related pathways were observed, including the Wnt signaling pathway. After elevated temperature and estrogen exposure, neomale and neofemale specimens were identified by a female-specific marker for the first time. RT-qPCR analysis showed the expression profile of ten selected sex-biased genes to be exhibited consistently in male and neomale and in female and neofemale, with the exception of the Amh and TfIIIa genes. Results suggested that these genes may play important roles in A. davidianus sex determination and gonad development. This provides a basis for further investigation of the molecular mechanisms of sex determination in amphibians. [ABSTRACT FROM AUTHOR]

Hierarchically porous P substituted HZSM‐5 (H[P, Al]‐ZSM‐5‐AT‐0.05 M) was successfully synthesized by isomorphous substitution method with introduced P atoms into ZSM‐5 zeolite frameworks followed by alkali treatment. H[P, Al]‐ZSM‐5‐AT‐0.05 M was characterized by XRD, ICP‐OES, SEM, FT‐IR, N2 adsorption‐desorption, NH3‐TPD, XPS, Py‐IR, and TG‐DTA, respectively. The surface area, pore volume, particle size and P/Al (molar ratio) are 328 m2.g−1, 0.23 cm3.g−1, 563 nm and 0.027, respectively. The catalytic performance of H[P, Al]‐ZSM‐5‐AT‐0.05 M in coupling reaction of methanol with 1‐butene was investigated in the fixed‐bed reactor. On the condition of reaction temperature at 500°C under atmosphere pressure, the main product is propylene with the selectivity and yield of 33.7% and 31.0%, respectively. Hydrogen transfer index was calculated to 0.24. Moreover, its diffusion limitation was investigated with the self‐etherification of benzyl alcohol reaction. The value of Thiele modulus (η) and effectiveness factor (ϕ) are 0.08 and 16.9, respectively. The scheme of isomorphously substituted method of introducing P into ZSM‐5 framework and catalytic performance over H[P, Al]‐ZSM‐5 and H[P, Al]‐ZSM‐5‐AT‐0.05 M in coupling methanol with 1‐butene. P substituted HZSM‐5 is treated with NaOH solution to form mesoporous zeolites. The result shows that H[P, Al]‐ZSM‐5‐AT‐0.05 M exhibited higher catalytic stability, higher apparent reaction rate, effectiveness factor and lower content of diffusion limitation in coupling of methanol with 1‐butene to propylene reaction. [ABSTRACT FROM AUTHOR]

Catalytic performance is influenced by the morphology and assembly of catalyst particles. Therefore, Zn ion‐doped HZSM‐5 zeolite with different morphological structures is prepared using post‐treatments of selective dissolution and recrystallization, causing silicon components to migrate from the interior to the exterior in the different template etching processes. The core–shell, hollow, and hierarchical core–shell Zn/HZSM‐5 microspheres with weak acid sites on the external surfaces are successfully synthesized. Hierarchical core–shell‐structured Zn/HZSM‐5 microspheres with a silicon‐rich surface layer are prepared using an etching method in n‐butylamine solution. Their catalytic activity is investigated in methanol aromatization. The functionalized morphological Zn/HZSM‐5 catalysts show good catalytic performance and the silicon‐rich surface layer improves selectivity of p‐xylene in the reaction of methanol to aromatics. Three morphological structured zeolite synthesis routes for p‐xylene are reported and selectivity is studied. Zn/HZSM‐5Si shows lower activity in the conversion of methanol to aromatics, but higher selectivity to xylene (particularly p‐xylene) considering benzene, toluene, and xylene. The Zn/HZSM‐5 catalysts treated in tetrapropylammonium hydroxide (TAPOH) and n‐butylamine solution exhibit excellent catalytic activity and stability in MTA reactions. [ABSTRACT FROM AUTHOR]

Efficient and rapid separation of emulsified oil/water mixtures is urgently needed and still remains a worldwide challenge. Even though traditional superhydrophobic/superoleophilic filtration membranes have demonstrated to be effective for separation of water-in-oil emulsions, they still suffer from complicated fabrication procedures and lower flux, resulting from their nanoscale pore size. Herein, green desert sands (50 μm to 1 mm) with under-oil superhydrophilicity were introduced, for the first time, to develop into a layer for efficient gravity-directed separation of various water-in-oil emulsions, which could avoid not only sophisticated filtration membranes fabrication process but also the use of expensive low energy materials of fluorosilane involved in traditional superhydrophobic materials. It is worth mentioning that the sand layer could serve as an adsorbent material with under-oil superhydrophilicity, achieving ultrafast gravity-driven separation of tiny water droplets from various water-in-oil emulsions with flux as high as 2342 L m−2 h even though the interspacing between the sand particles is greater than the size of emulsified droplets. Moreover, the sand can be abundantly obtained from deserts, which is another advantage that the current filtrate materials do not possess. In summary, this study provides a general avenue to design under-oil superhydrophilic materials for rapid separation of water-in-oil emulsions. Such an approach can provide some new perspectives for fabrication of novel emulsion-separating materials. [ABSTRACT FROM AUTHOR]

Areas and spatial distribution information of paddy rice are important for managing food security, water use, and climate change. However, there are many difficulties in mapping paddy rice, especially mapping multi-season paddy rice in rainy regions, including differences in phenology, the influence of weather, and farmland fragmentation. To resolve these problems, a novel multi-season paddy rice mapping approach based on Sentinel-1A and Landsat-8 data is proposed. First, Sentinel-1A data were enhanced based on the fact that the backscattering coefficient of paddy rice varies according to its growth stage. Second, cropland information was enhanced based on the fact that the NDVI of cropland in winter is lower than that in the growing season. Then, paddy rice and cropland areas were extracted using a K-Means unsupervised classifier with enhanced images. Third, to further improve the paddy rice classification accuracy, cropland information was utilized to optimize distribution of paddy rice by the fact that paddy rice must be planted in cropland. Classification accuracy was validated based on ground-data from 25 field survey quadrats measuring 600 m × 600 m. The results show that: multi-season paddy rice planting areas effectively was extracted by the method and adjusted early rice area of 1630.84 km2, adjusted middle rice area of 556.21 km2, and adjusted late rice area of 3138.37 km2. The overall accuracy was 98.10%, with a kappa coefficient of 0.94. [ABSTRACT FROM AUTHOR]

Spatial variation of soil respiration (Rs) in cropland ecosystems must be assessed to evaluate the global terrestrial carbon budget. This study aims to explore the spatial characteristics and controlling factors of Rs in a cropland under winter wheat and summer maize rotation in the North China Plain. We collected Rs data from 23 sample plots in the cropland. At the late jointing stage, the daily mean Rs of summer maize (4.74 μmol CO2 m-2 s-1) was significantly higher than that of winter wheat (3.77μmol CO2 m-2 s-1). However, the spatial variation of Rs in summer maize (coefficient of variation, CV = 12.2%) was lower than that in winter wheat (CV = 18.5%). A similar trend in CV was also observed for environmental factors but not for biotic factors, such as leaf area index, aboveground biomass, and canopy chlorophyll content. Pearson’s correlation analyses based on the sampling data revealed that the spatial variation of Rs was poorly explained by the spatial variations of biotic factors, environmental factors, or soil properties alone for winter wheat and summer maize. The similarly non-significant relationship was observed between Rs and the enhanced vegetation index (EVI), which was used as surrogate for plant photosynthesis. EVI was better correlated with field-measured leaf area index than the normalized difference vegetation index and red edge chlorophyll index. All the data from the 23 sample plots were categorized into three clusters based on the cluster analysis of soil carbon/nitrogen and soil organic carbon content. An apparent improvement was observed in the relationship between Rs and EVI in each cluster for both winter wheat and summer maize. The spatial variation of Rs in the cropland under winter wheat and summer maize rotation could be attributed to the differences in spatial variations of soil properties and biotic factors. The results indicate that applying cluster analysis to minimize differences in soil properties among different clusters can improve the role of remote sensing data as a proxy of plant photosynthesis in semi-empirical Rs models and benefit the acquisition of Rs in cropland ecosystems at large scales. [ABSTRACT FROM AUTHOR]

Lhx9 is an LIM (named for the first three proteins in which the domain was found, Lin-11, Isl1 and Mec-3) homeodomain protein involved in development and differentiation of the gonad. In this study, we isolated the full-length Lhx9 and Lhx9 α from Andrias davidianus, detected the tissue distribution and analysed the methylation of the promoters. We identified Lhx9 of 1411 bp and Lhx9 α of 1153-bp length, differing in the 3 $^{\prime }$ -flanking region, encoding 399 and 330 amino acids, respectively. The Lhx9 gene was detected primarily in liver, ovary and heart with moderate expression in brain, pituitary, intestine and spleen, and low expression in the remaining examined tissues, while Lhx9 α expression was high in heart, pituitary and liver, and low in spleen and stomach. Significantly higher Lhx9 expression was observed in ovary than in testis, with no differences in Lhx9 α expression between testis and ovary observed. Bisulphite sequencing revealed significantly higher methylation in testis compared to ovary. The methylation level of CpG sites -733, -673, -615 and -594 exhibited significantly higher levels in testis than in ovary, which was negatively correlated with Lhx9 expression. The methylation and expression patterns suggested that promoter methylation suppressed expression of Lhx9 in A. davidianus. [ABSTRACT FROM AUTHOR]

ABSTRACT Foxl2 and FTZ-F1 play a crucial role in the regulation of gonad development in fish and mammals, but studies of their function in amphibians are scarce. We isolated the full length of Foxl2 ( adFoxl2) and Ftz-F1 ( adFtz-f1) cDNA from the Chinese giant salamander Andrias davidianus and quantified its expression in various tissues and developing gonads. The adFoxl2 gene encodes 301aa including a conserved forkhead box, and the adFtz-f1 gene encodes 467aa containing an Ftz-F1 box. The amino acid sequences showed high homology with other amphibians. adFoxl2 expression was high in ovary, whereas adFtz-f1 was higher in testis, moderate in pituitary, ovary, and kidney; and low in the remaining tested tissues. Expression of adFoxl2 gradually increased from 1Y to 5Y in ovary, whereas adFtz-f1 expression gradually decreased in testis. In addition, adFoxl2 and adFtz-f1 were detected in granulosa cell in ovary and in spermatocytes in testis. The adFoxl2 transcription was inhibited in brain and ovary after treatment with methyltestosterone and with letrozole, whereas adFtz-f1 expression was upregulated. High-temperature suppressed the expression of adFxl2 in ovary and enhanced the transcription of adFtz-f1. These results suggest that adFoxl2 functioned in ovary differentiation, whereas adFtz-f1 played a role in testis development, which lays a foundation for study of the sex differentiation mechanism in A. davidianus. [ABSTRACT FROM AUTHOR]

Prolactin receptor (PRLR) is a protein associated with reproduction in mammals and with osmoregulation in fish. In this study, the complete length of Chinese giant salamander Andrias davidianus prolactin receptor (AD-prlr) was cloned. Andrias davidianus prlr expression was high in the kidney, pituitary, and ovary and low in other examined tissues. The AD-prlr levels were higher in ovary than in testis, and increased in ovaries with age from 1 to 6 years. To determine effect of exogenous androgen and aromatase inhibitor on AD-prlr expression, methyltestosterone (MT) and letrozole (LE)were injected, resulting in decreased AD-prlr in both brain and ovary, with MT repressing prlr transcriptionmore rapidly than did LE. Themolecular evolution of prlr was assessed, and found to have undergone a complex evolution process. The obranch-site test detected four positively selected sites in ancestral lineages prior to the separation of mammals and birds. Fourteen sites underwent positive selection in ancestral lineages of birds and sixwere positively selected in amphibians. The site model showed that 16, 7, and 30 sites underwent positive selection in extantmammals, amphibians, and birds, respectively. The positively selected sites in amphibians were located outside the transmembrane domain, with four in the extracellular and three in the intracellular domain, indicating that the transmembrane region might be conserved and essential for protein function. Our findings provide a basis for further studies of AD-prlr function and molecular evolution in Chinese giant salamander. [ABSTRACT FROM AUTHOR]

Because canola is a major oilseed crop, accurately determining its planting areas is crucial for ensuring food security and achieving UN 2030 sustainable development goals. However, when canola is extracted using remote-sensing data, winter wheat causes serious interference because it has a similar growth cycle and spectral reflectance characteristics. This interference seriously limits the classification accuracy of canola, especially in mixed planting areas. Here, a novel canola flower index (CFI) is proposed based on the red, green, blue, and near-infrared bands of Sentinel-2 images to improve the accuracy of canola mapping, based on the finding that spectral reflectance of canola on the red and green bands is higher than that of winter wheat during the canola flowering period. To investigate the potential of the CFI for extracting canola, the IsoData, support vector machine (SVM), and random forest (RF) classification methods were used to extract canola based on Sentinel-2 raw images and CFI images. The results show that the average overall accuracy and kappa coefficient based on CFI images were 94.77% and 0.89, respectively, which were 1.05% and 0.02, respectively, higher than those of the Sentinel-2 raw images. Then we found that a threshold of 0.14 on the CFI image could accurately distinguish canola from non-canola vegetation, which provides a solution for automatic mapping of canola. The overall classification accuracy and kappa coefficient of this threshold method were 96.02% and 0.92, which were very similar to those of the SVM and RF methods. Moreover, the advantage of the threshold classification method is that it reduces the dependence on training samples and has good robustness and high classification efficiency. Overall, this study shows that CFI and Sentinel-2 images provide a solution for automatic and accurate canola extraction. [ABSTRACT FROM AUTHOR]

The Ag3 PO4 and Ag3 PO4 sonocatalysts with surface enrichment of Br− anions ( Br- Ag3 PO4) were synthesized using a facile precipitate process. Various analysis, including X-ray diffraction, transmission electron microscopy, scanning electron microscope, Brunauer-Emmett-Teller, photoluminescence (PL) spectra, and UV-Vis absorption spectra were carried out to investigate the property and structure. The effect of a variety of changing conditions on ultrasonic degradation of organic dye has been investigated. Both of them exhibited obvious activity for sonocatalytic degradation of organic dyes. However, Br- Ag3 PO4 sonocatalysts showed much higher activity than that of Ag3 PO4. By XRD analysis, the Br− anions of the surface of Ag3 PO4 has been transformed into AgBr in the preparation process. The high activity could be attributed to AgBr for modifying Ag3 PO4. By detecting hydroxyl radicals (· OH) in the reactive solution, we found that AgBr on the surface of Ag3 PO4 can help to produce a lot of additional · OH radicals. These · OH radicals may be significant reason to improve Ag3 PO4 activity, which further proved the · OH radical mechanism of Ag3 PO4 degradation of dyes under ultrasonic radiation. In addition, kinetic analysis and sonocatalytic mechanism were discussed in detail. [ABSTRACT FROM AUTHOR]

Asian swamp eel (Monopterus albus, Zuiew 1793) is a commercially important fish due to its nutritional value in Eastern and Southeastern Asia. One local strain of M. albus distributed in the Jianghan Plain of China has been subjected to a selection breeding program because of its preferred body color and superiority of growth and fecundity. Some members of the genus Monopterus have been reclassified into other genera recently. These classifications require further phylogenetic analyses. In this study, the complete mitochondrial genomes of the breeds of M. albus were decoded using both PacBio and Illumina sequencing technologies, then phylogenetic analyses were carried out, including sampling of M. albus at five different sites and 14 species of Synbranchiformes with complete mitochondrial genomes. The total length of the mitogenome is 16,621 bp, which is one nucleotide shorter than that of four mitogenomes of M. albus sampled from four provinces in China, as well as one with an unknown sampling site. The gene content, gene order, and overall base compositions are almost identical to the five reported ones. The results of maximum likelihood (ML) and Bayesian inference analyses of the complete mitochondrial genome and 13 protein-coding genes (PCGs) were consistent. The phylogenetic trees indicated that the selecting breed formed the deepest branch in the clade of all Asian swamp eels, confirmed the phylogenetic relationships of four genera of the family Synbranchidae, also providing systematic phylogenetic relationships for the order Synbranchiformes. The divergence time analyses showed that all Asian swamp eels diverged about 0.49 million years ago (MYA) and their common ancestor split from other species about 45.96 MYA in the middle of the Miocene epoch. Altogether, the complete mitogenome of this breed of M. albus would serve as an important dataset for germplasm identification and breeding programs for this species, in addition to providing great help in identifying the phylogenetic relationships of the order Synbranchiformes. [ABSTRACT FROM AUTHOR]

Sentinel-2 imagery is an unprecedented data source with high spatial, spectral and temporal resolution in addition to free access. The objective of this paper was to evaluate the potential of using Sentinel-2 data to map winter crops in the early growth stage. Analysis of three winter crop types—winter garlic, winter canola and winter wheat—was carried out in two agricultural regions of China. We analysed the spectral characteristics and vegetation index profiles of these crops in the early growth stage and other land cover types based on Sentinel-2 images. A decision tree classification model was built to distinguish the crops based on these data. The results demonstrate that winter garlic and winter wheat can be distinguished four months before harvest, while winter canola can be distinguished two months before harvest. The overall classification accuracy was 96.62% with a kappa coefficient of 0.95. Therefore, Sentinel-2 images can be used to accurately identify these winter crops in the early growth stage, making them an important data source in the field of agricultural remote sensing. [ABSTRACT FROM AUTHOR]

In fish, sperm motility activation is one of the most essential procedures for fertilization. Previous studies have mainly focused on the external environmental effects and intracellular signals in sperm activation; however, little is known about the metabolic process of sperm motility activation in fish. In the present study, using ricefield eel (Monopterus albus) sperm as a model, metabonomics was used to analyze the metabolic mechanism of the sperm motility activation in fish. Firstly, 529 metabolites were identified in the sperm of ricefield eel, which were clustered into the organic acids, amino acids, nucleotides, benzene, and carbohydrates, respectively. Among them, the most abundant metabolites in sperm were L-phenylalanine, DL-leucine, L-leucine, lysolecithin choline 18:0, L-tryptophan, adenine, hypoxanthine, 7-Methylguanine, shikimic acid, and L-tyrosine. Secondly, compared to pre-activated sperm, the level of S-sulfo-L-cysteine and L-asparagine were both increased in the post-activated sperm. Ninety-two metabolites were decreased in the post-activated sperm, including quinic acid, acetylsalicylic acid, 7,8-dihydro L-biopterin, citric acid, glycylphenylalanine, and dihydrotachysterol (DHT). Finally, basing on the pathway analysis, we found that the changed metabolites in sperm motility activation were mainly clustered into energy metabolism and anti-oxidative stress. Fish sperm motility activation would be accompanied by the release of a large amount of energy, which might damage the genetic material of sperm. Thus, the anti-oxidative stress function is a critical process to maintain the normal physiological function of sperm. [ABSTRACT FROM AUTHOR]

Garlic and winter wheat are major economic and grain crops in China, and their boundaries have increased substantially in recent decades. Updated and accurate garlic and winter wheat maps are critical for assessing their impacts on society and the environment. Remote sensing imagery can be used to monitor spatial and temporal changes in croplands such as winter wheat and maize. However, to our knowledge, few studies are focusing on garlic area mapping. Here, we proposed a method for coupling active and passive satellite imagery for the identification of both garlic and winter wheat in Northern China. First, we used passive satellite imagery (Sentinel-2 and Landsat-8 images) to extract winter crops (garlic and winter wheat) with high accuracy. Second, we applied active satellite imagery (Sentinel-1 images) to distinguish garlic from winter wheat. Third, we generated a map of the garlic and winter wheat by coupling the above two classification results. For the evaluation of classification, the overall accuracy was 95.97%, with a kappa coefficient of 0.94 by eighteen validation quadrats (3 km by 3 km). The user's and producer's accuracies of garlic are 95.83% and 95.85%, respectively; and for the winter wheat, these two accuracies are 97.20% and 97.45%, respectively. This study provides a practical exploration of targeted crop identification in mixed planting areas using multisource remote sensing data. [ABSTRACT FROM AUTHOR]

Graphene oxide–supported β-cyclodextrin was prepared with graphene oxide and β-cyclodextrin as raw materials and epichlorohydrin as crosslinking agent, respectively. It was characterized by the methods of Raman spectroscopy, FT-IR, and SEM. The graphene oxide–supported β-cyclodextrin showed excellent adsorption performance for p-nitrophenol, and the absorption equilibrium can be achieved within 2 h. The adsorptive capacity is 117.28 mg/g at adsorption temperature of 313 K and pH at 8.0. Adsorption isotherms showed that the adsorption capacity increases with the increases of temperature and adsorption process could be better fitted by Langmuir isotherm (R2 > 0.995). Thermodynamic functions (ΔG, ΔH, and ΔS) investigation showed that the adsorption is spontaneous, endothermic, and random. The adsorption kinetics of p-nitrophenol over graphene oxide–supported β-cyclodextrin is conformed to a pseudo-second-order process. This study has suggested that the graphene oxide–supported β-cyclodextrin could play an efficient and beneficial source of the adsorbent for the purpose of eliminating p-nitrophenol from aqueous solution. [ABSTRACT FROM AUTHOR]

Accurately quantifying spatiotemporal changes in surface water is essential for water resources management, nevertheless, the dynamics of Poyang Lake surface water areas with high spatiotemporal resolution, as well as its responses to climate change, still face considerable uncertainties. Using the time series of Sentinel-1 images with 6- or 12-day intervals, the Sentinel-1 water index (SWI), and SWI-based water extraction model (SWIM) from 2015 to 2020 were used to document and study the short-term characteristics of southwest Poyang Lake surface water. The results showed that the overall accuracy of surface water area was satisfactory with an average of 91.92%, and the surface water area ranged from 129.06 km2 on 2 March 2017 to 1042.57 km2 on 17 July 2016, with significant intra- and inter-month variability. Within the 6-day interval, the maximum change of lake area was 233.42 km2 (i.e., increasing from 474.70 km2 up to 708.12 km2). We found that the correlation coefficient between the water area and the 45-day accumulated precipitation reached to 0.75 (p < 0.001). Moreover, a prediction model was built to predict the water area based on climate records. These results highlight the significance of high spatiotemporal resolution mapping for surface water in the erratic southwest Poyang Lake under a changing climate. The automated water extraction algorithm proposed in this study has potential applications in delineating surface water dynamics at broad geographic scales. [ABSTRACT FROM AUTHOR]