α-Glucosidase Inhibitors From the Coral-Associated Fungus Aspergillus terreus

Nine novel butenolide derivatives, including four pairs of enantiomers, named (±)-asperteretones A–D (1a/1b–4a/4b), and a racemate, named asperteretone E (5), were isolated and identified from the coral-associated fungus Aspergillus terreus. All the structures were established based on extensive spectroscopic analyses, including HRESIMS and NMR data. The chiral chromatography analyses allowed the separation of (±)-asperteretones A–D, whose absolute configurations were further confirmed by experimental and calculated electronic circular dichroism (ECD) analysis. Structurally, compounds 2–5 represented the first examples of prenylated γ-butenolides bearing 2-phenyl-3-benzyl-4H-furan-1-one motifs, and their crucial biogenetically related metabolite, compound 1, was uniquely defined by an unexpected cleavage of oxygen bridge between C-1 and C-4. Importantly, (±)-asperteretal D and (4S)-4-decarboxylflavipesolide C were revised to (±)-asperteretones B (2a/2b) and D (4), respectively. Additionally, compounds 1a/1b–4a/4b and 5 were evaluated for the α-glucosidase inhibitory activity, and all these compounds exhibited potent inhibitory potency against α-glucosidase, with IC50 values ranging from 15.7 ± 1.1 to 53.1 ± 1.4 μM, which was much lower than that of the positive control acarbose (IC50 = 154.7 ± 8.1 μM), endowing them as promising leading molecules for the discovery of new α-glucosidase inhibitors for type-2 diabetes mellitus treatment

Construction of Hierarchical MoSe2 Hollow Structures and Its Effecton Electrochemical Energy Storage and Conversion

Metal selenides have attracted increased attentionas promising electrode materials for electrochemical energy storageand conversion systems including metal-ion batteries and watersplitting. However, their practical application is greatly hindered bycollapse of the microstructure, thus leading to performance fading.Tuning the structure at nanoscale of these materials is an effectivestrategy to address the issue. Herein, we craft MoSe2withhierarchical hollow structures via a facile bubble-assistedsolvothermal method. The temperature-related variations of thehollow interiors are studied, which can be presented as solid, yolk−shell, and hollow spheres, respectively. Under the simultaneousaction of the distinctive hollow structures and interconnectionsamong the nanosheets, more intimate contacts between MoSe2and electrolyte can be achieved, thereby leading to superior electrochemical properties. Consequently, the MoSe2hollownanospheres prepared under optimum conditions exhibit optimal electrochemical activities, which hold an initial specificcapacity of 1287 mA h g−1and maintain great capacity even after 100 cycles as anode for Li-ion battery. Moreover, the Tafelslope of 58.9 mV dec−1for hydrogen evolution reaction is also attained

Energy Coordinative Optimization of Wind-Storage-Load Microgrids Based on Short-Term Prediction

According to the topological structure of wind-storage-load complementation microgrids, this paper proposes a method for energy coordinative optimization which focuses on improvement of the economic benefits of microgrids in the prediction framework. First of all, the external characteristic mathematical model of distributed generation (DG) units including wind turbines and storage batteries are established according to the requirements of the actual constraints. Meanwhile, using the minimum consumption costs from the external grid as the objective function, a grey prediction model with residual modification is introduced to output the predictive wind turbine power and load at specific periods. Second, based on the basic framework of receding horizon optimization, an intelligent genetic algorithm (GA) is applied to figure out the optimum solution in the predictive horizon for the complex non-linear coordination control model of microgrids. The optimum results of the GA are compared with the receding solution of mixed integer linear programming (MILP). The obtained results show that the method is a viable approach for energy coordinative optimization of microgrid systems for energy flow and reasonable schedule. The effectiveness and feasibility of the proposed method is verified by examples

Three new amide derivatives from the fungus Alternaria brassicicola

Abstract Three new amide derivatives (alteralkaloids A–C, 1–3) and three known alkaloids (4–6) were afforded after phytochemical investigation of fungus Alternaria brassicicola. The structures of these compounds were confirmed by NMR spectroscopic and HRESIMS data. Furthermore, the absolute configuration of 1 was determined using the single-crystal X-ray diffraction analysis. Compounds 1–3 belong to a class of amide derivatives that have not been found in nature before, sharing the same characteristic signals of the butyl moiety and amide group. These isolated compounds mentioned above were tested for the cytotoxic activity. Graphical Abstrac

Two Different Inoculation Methods Unveiled the Relative Independence of DON Accumulation in Wheat Kernels from Disease Severity on Spike after Infection by Fusarium Head Blight

Fusarium head blight (FHB) causes wheat yield loss and mycotoxin (deoxynivalenol, DON) accumulation in wheat kernel. Developing wheat cultivars with overall resistance to both FHB spread within a spike and DON accumulation in kernels is crucial for ensuring food security and food safety. Here, two relatively novel inoculation methods, bilateral floret inoculation (BFI) and basal rachis internode injection (BRII), were simultaneously employed to evaluate disease severity and DON content in kernels in a segregating population of recombinant inbred lines (RILs) developed from Ning 7840 (carrying Fhb1) and Clark (without Fhb1). Under both inoculation methods, four contrasting combinations of disease severity and DON content were identified: high severity/high DON (HSHD), high severity/low DON (HSLD), low severity/high DON (LSHD) and low severity/low DON (LSLD). Unexpectedly, the BRII method clearly indicated that disease severity was not necessarily relevant to DON concentration. The effects of Fhb1 on disease severity, and on DON concentrations, agreed very well across the two methods. Several lines carrying Fhb1 showed extremely higher severity and (or) DON content under both inoculation methods. The “Mahalanobis distance” (MD) method was used to rate overall resistance of a line by inclusion of both disease severity and DON content over both methods to select LSLD lines

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 To determine the relative contribution rate of environmental variables to shallow landslide risk for forestland, and clarify the key vegetation factors affecting the shallow landslide risk and their disaster reduction range, seventeen environmental variables were selected, and the Maximum entropy (MaxEnt) model was used to determine the relative contribution rate of these environmental variables to the prediction of shallow landslide risk for forestland.  </p

Biomimetic structure design and construction of cactus-like MoS2/Bi19Cl3S27 photocatalysts for efficient hydrogen evolution

Cacti grown in arid areas have developed intrinsic water management systems, inspired by the cactus which has survived cruel natural selection, uncommon cactus-like MoS2/Bi19Cl3S27 heterostructures have been successfully constructed in this work. Resembling the trichome and epidermis of a cactus stem, vertically aligned MoS2 along with a carbon species hydrolyzed from glucose on Bi19Cl3S27 comprised the unique biomimetic structure. During the photocatalytic process of MoS2/Bi19Cl3S27 heterostructures, the characteristic biomimetic structure endows the heterostructures with greatly enhanced light adsorption and charge separation capabilities, the whole hydrogen evolution reaction was boosted by the combination of optimized charge and mass transfer paths, like the plant morphogenesis of a cactus which plays a significant role in mucilage-based energy-transmission. As a consequence, the improved photocatalytic H2 evolution rate reaches up to 876.6 μmol g−1 h−1 with an optimal loading of 5 wt% MoS2. The successful preparation of biomimetic structured MoS2/Bi19Cl3S27 samples with good stability shows that bismuth-based materials have great potential for applications in energy conversion systems, while providing enlightenment for the design of other biomimetic structured nanomaterials

A Rice Mapping Method Based on Time-Series Landsat Data for the Extraction of Growth Period Characteristics

The rapid and accurate acquisition of rice cultivation information is very important for the management and assessment of rice agriculture and for research on food security, the use of agricultural water resources, and greenhouse gas emissions. Rice mapping methods based on phenology have been widely used but further studies are needed to clearly quantify the rice characteristics during the growth cycle. This paper selected the area where rice agriculture has undergone tremendous changes as the observation object. The rice areas were mapped in three time periods during the period from 1993 to 2016 by combining the characteristics of the harvested areas, flooded areas, and the time interval when harvesting and flooding occurred. An error matrix was used to determine the mapping accuracy. After exclusion of clouds and cloud shadows, the overall accuracy of the paddy fields was higher than 90% (90.5% and 93.5% in period 1 and period 3, respectively). Mixed pixels, image quality, and image acquisition time are important factors affecting the accuracy of rice mapping. The rapid economic development led to an adjustment of people&rsquo;s diets and presumably this is the main reason why rice cultivation is no longer the main agricultural production activity in the study area

Enhancing potassium-ion battery performance by MoS2 coated nitrogen-doped hollow carbon matrix

© 2020 Elsevier B.V. As an important alternative to lithium-ion batteries (LIBs), potassium-ion batteries (PIBs) have attracted much attention due to the abundance and low cost of potassium, however, it is still a great challenge to select suitable anode materials to accommodate the large-size of K-ion. Herein, MoS2 nanosheets were coated on the porous carbon polyhedron derived from zeolite imidazole framework-8 (designated as PCP@MoS2) and employed as the anode materials for PIBs. Benefiting from the high electrical conductivity, strong structure stability of the nitrogen-doped carbon polyhedron and the layered crystal structure of MoS2, the reversible capacity can be maintained at 375 mA h g−1 after 100 cycles at 100 mA g−1, 200 mA h g−1 after 200 cycles at 500 mA g−1 as well as excellent rate property. The excellent electrochemical performance can be attributed to the unique hybrid structures and the synergistic effects between MoS2 and N doped porous carbon polyhedron, which could enhance the electronic conductivity, shorten the K-ion diffusion distance, mitigate the agglomeration of the MoS2 nanosheets, relieve the volume variation, and provide plenty of active sites for K ion accomodation

Hierarchical Ni-Co-O-C-P hollow tetragonal microtubes grown on Ni foam for efficient overall water splitting in alkaline media

Exploring low-cost and highly efficient non-noble bifunctional electrocatalysts with high performances for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for large-scale sustainable energy systems. Herein, the Ni-Co-O-C-P hollow tetragonal microtubes grown on 3D Ni foam (Ni-Co-O-C-P/NF) was synthesized via a one-step solvothermal method and followed by a simple carbon coating and in situ phosphorization treatment. Benefiting from the unique open and hierarchical nano-architectures, the as prepared Ni-Co-O-C-P/NF presents a high activity and durability for both the HER and OER in alkaline media. The overall-water-splitting reaction requires a low cell voltage (1.54 V @ 10 mA cm(-2)) in 1 M KOH when Ni-Co-O-C-P/NF is used as both the anode and cathode. The highly flexible structure can provide a large amount of exposed active sites and shorten the mass transport distance. Furthermore, bimetallic phosphides also favor the electrocatalysis due to the higher electronic conductivity and the synergetic effect. This work demonstrated a promising bifunctional electrocatalyst for water electrolysis in alkaline media with potential in future applications