Abstract In recent years, China has organized three batches of high-proportion renewable energy generation bases, with the aim of resolving the geographical imbalance between renewable energy supply ...and consumption. Renewable electricity is transported from the resource-abundant western regions to the electricity-demanding eastern regions. Given the inherent variability and unpredictability of wind power and photovoltaic power generation, there is a pressing need for additional support from more reliable energy generation sources, including coal-fired power and concentrated solar power (CSP). This paper presents a power system optimization planning model that incorporates the internal energy transfer of CSP. It proposes strategies for establishing high-proportion renewable energy generation bases supported by both coal-fired power and CSP. Furthermore, it investigates the primary constraints affecting the energy generation base. The study also compares the peak shaving depth and output characteristics between coal-fired power and CSP. Moreover, this paper introduces the method of natural gas supplemental combustion to enhance the power supply stability of CSP, enabling the renewable energy generation base to supply electricity through conventional DC transmission.
An inverse‐electron‐demand Diels–Alder (IEDDA) reaction could complement the conventional normal‐electron‐demand Diels–Alder reaction in the synthesis of six‐membered carbocycles. However, catalytic ...asymmetric all‐carbon‐based IEDDA reactions are underdeveloped. Herein, we disclosed a copper‐catalyzed asymmetric IEDDA reaction using electron‐deficient 3‐carboalkoxyl‐2‐pyrones and electronically unbiased indenes as reactants. This method enables the rapid and enantioselective construction of a wide range of hexahydrofluorenyl bridged‐lactone scaffolds. Using this method, asymmetric total syntheses of cephanolides A and B were accomplished.
Catalytic asymmetric all‐carbon‐based inverse‐electron‐demand Diels–Alder reactions of 2‐pyrones with electronically unbiased indenes have been realized. This method enables the rapid and enantioselective construction of a wide range of hexahydrofluorenyl bridged‐lactone scaffolds. Based on this method, asymmetric total syntheses of cephanolides A and B have been accomplished.
An efficient cascade reaction of tryptamine‐derived isocyanides with C,N‐cyclic azomethine imines is described. The polycyclic pyrrolo2,3‐cquinoline derivatives, which benefited from rearrangement ...process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40–87 %) under metal‐free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N‐cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in‐depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine‐derived isocyanide‐based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.
Natural‐product‐like polycyclic pyrrolo2,3‐cquinoline derivatives have been easily constructed in one‐step process from easily available starting materials. This reaction involves two ring enlargements and four heterocyclic ring formations via cascade rearrangement process. DFT studies reveal the crucial hydrogen‐bonding interaction in the detailed mechanistic investigation.
Non‐small‐cell lung cancer (NSCLC), with its aggressive biological behavior, is one of the most diagnosed cancers. Tumor‐associated inflammatory cells play important roles in the interaction between ...chronic inflammation and lung cancer, however the mechanisms involved are far from defined. In the present study, by developing an orthotopic NSCLC mouse model based on chronic inflammation, we proved that an inflammatory microenvironment accelerated the growth of orthotopic xenografts in vivo. Tumor‐associated macrophages, the most abundant population of inflammatory cells, were identified. Treatment with macrophage‐conditioned medium (MCM) promoted the growth and migration of NSCLC cells. Using bioinformatics analysis, we identified downregulated PP2Ac expression in NSCLC cells upon treatment with MCM. We further confirmed that this downregulation was executed in an NF‐κB pathway‐dependent manner. As IκB kinase (IKK) has been proved to be a substrate of PP2Ac, inhibition on PP2Ac could result in amplification of NF‐κB pathway signaling. Overexpression of PP2Ac, or the dominant‐negative forms of IKK or IκB, attenuated the acceleration of growth and metastasis by MCM. Using bioinformatics analysis, we further identified that CXCL1 and COL6A1 could be downstream of NF‐κB/PP2Ac pathway. Luciferase assay and ChIP assay further confirmed the location of response elements on the promoter regions of CXCL1 and COL6A1. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted proliferation and migration.
Tumor‐associated macrophages, the prominent type of inflammatory cells in non‐small‐cell lung cancer, can promote the growth and metastasis of cancer cells. Overexpression of PP2Ac, or the dominant‐negative forms of IKK or IκB, attenuated the acceleration on cancer cell growth and metastasis by TAMs. CXCL1 and COL6A1 could be downstream of NF‐κB/PP2Ac pathway. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted cancer cell proliferation and migration.
Herein, we show that the combination of the Birch reduction of readily available anisole derivatives and the catalytic asymmetric inverse‐electron‐demand Diels–Alder reaction of 2‐pyrones can serve ...as a powerful platform for the diverse synthesis of synthetically important cis‐decalin scaffolds. Enabled by a well‐modified chiral bis(oxazoline) ligand/CuII complex, a wide range of polysubstituted cis‐decalin scaffolds with up to six contiguous stereocenters were generated efficiently. The synthetic potential of this method is demonstrated by the concise synthesis of the sesquiterpene (+)‐occidentalol and a key intermediate for seven triterpenes. Mechanistic studies suggest the 1,3‐cyclohexadienes formed in situ are the key intermediates, and efficient kinetic resolution occurs when C2‐ and/or C3‐substituted 1,4‐cyclohexadienes are utilized as substrates. DFT calculations elucidated that the Diels–Alder reaction proceeds in a stepwise fashion and revealed the origins of the stereoselectivities.
Asymmetric synthesis of highly functionalized chiral cis‐decalins was realized by merging Birch reduction and a tandem olefin migration/asymmetric IEDDA reaction. Up to six contiguous and two quaternary stereocenters could be formed in one step by efficient kinetic resolution. The synthetic value of the approach is illustrated by the concise total synthesis of (+)‐occidentalol and the synthesis of a key intermediate for seven triterpenes.
An enantioselective chemical synthesis of arene cis‐dihydrodiols has been realized from 2‐pyrones through sequential ytterbium‐catalyzed asymmetric inverse‐electron‐demand Diels–Alder (IEDDA) ...reaction of 2‐pyrones and retro‐Diels–Alder extrusion of CO2. By using this strategy, a series of substituted arene cis‐dihydrodiols can be obtained efficiently with high enantioselectivity (>99 % ee in many cases). Based on this strategy, efficient and concise asymmetric total syntheses of (+)‐MK7607 and 1‐epi‐(+)‐MK7607 were accomplished.
An enantioselective chemical synthesis of arene cis‐dihydrodiols from 2‐pyrones through sequential ytterbium‐catalyzed asymmetric inverse‐electron‐demand Diels–Alder (IEDDA) reaction of 2‐pyrones and retro‐Diels–Alder extrusion of CO2 is reported. This method provides a powerful chemical method for the enatioselective synthesis of arene cis‐dihydrodiols as a reliable alternative to traditional enzymatic catalysis.
Pesticides directly pollute the environment and contaminate foods ultimately being absorbed by the human body. Their residues contain highly toxic substances that have been found to cause serious ...problems to human health even at very low concentrations. The gold standard method, gas/liquid chromatography combined with mass spectroscopy, has been widely used for the detection of pesticide residues. However, these methods have some drawbacks such as complicated pretreatment and cleanup steps. Recent technological advancements of surface-enhanced Raman spectroscopy (SERS) have promoted the creation of alternative detection techniques. SERS is a useful detection tool with ultrasensitivity and simpler protocols. Present SERS-based pesticide residue detection often uses standard solutions of target analytes in conjunction with theoretical Raman spectra calculated by density functional theory (DFT) and actual Raman spectra detected by SERS. SERS is quite a promising technique for the direct detection of pesticides at trace levels in liquid samples or on the surface of solid samples following simple extraction to increase the concentration of analytes. In this review, we highlight recent studies on SERS-based pesticide detection, including SERS for pesticide standard solution detection and for pesticides in/on food samples. Moreover, in-depth analysis of pesticide chemical structures, structural alteration during food processing, interaction with SERS substrates, and selection of SERS-active substrates is involved.
A novel copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides has been developed. The regioselectivity of the alkylboration was controlled by subtle ...differences in the ligand structure. The reaction thus enables the practical, regiodivergent synthesis of two different alkyl boronic esters with complex structures from a single alkene.
One way or another: The copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides is described. The regioselectivity of the carboboration can be controlled by fine‐tuning the ligand structure.
The synthesis of 2‐azido‐1‐benzoylindolin‐3‐yl 2‐benzamidobenzoate commencing from (1H‐indol‐1‐yl)(phenyl)methanone and trimethylsilyl azide (TMSN3) under oxygen atmosphere is described in this ...paper. This transformation proceeds via a sequential dearomatization and ring‐opening cascade reaction of indoles in a cascade manner.
On 3 January 2019, the Chang'e‐4 (CE‐4) touched down on the Von Karman crater located inside the South Pole‐Aitken Basin, providing for the first time the opportunity for in situ measurements of the ...lunar regolith at the farside of the Moon. The CE‐4 ground penetrating radar reveals that fine‐grained regolith, coarse impact ejecta, and fractured bedrocks lie beneath the exploration path of the Yutu‐2 rover. The variations of regolith permittivity with depth and the radargrams indicate that the CE‐4 site has a fine‐grained regolith layer thickness of 11.1 m, which is about 1.3–3 times higher than the in situ measurement results at the Apollo and Chang'e‐3 (CE‐3) sites except for Apollo 16, possibly due to a faster weathering rate of ejecta deposits compared with coherent basalt substrates. The penetration depth of CE‐4 is about 2.85 times (in terms of round‐way delay) deeper than CE‐3, probably due to the differences in abundances of ilmenite and rocks in the regolith.
Plain Language Summary
CE‐4 is the first craft in history to land on the lunar farside. Its rover is equipped with a ground‐penetrating radar (GPR), the same as the one mounted on the CE‐3 rover, which uses pulses of electromagnetic energy to reveal the subsurface structure and properties, especially useful to study the lunar soil layer (“regolith”) that mantles most of the lunar surface. The results from the GPR show that the thickness of the regolith at the CE‐4 site is 1.3–3 times higher than the in situ measurements at the Apollo 11,12,14,15, 17, and CE‐3 sites even though the ages of the surfaces of Apollo 11 and Apollo 17 are thought to be comparable with that of the CE‐4 site. It implies a faster regolith growth speed at the CE‐4 site. The mineral mix of the surface materials at the CE‐4 site is different from that at the CE‐3: this results in less radar signal attenuation, thus increasing the detection limit up to the depth of 35 m, 2.85 times deeper than the CE‐3.
Key Points
The LPR measurements at the CE‐4 landing site reveal that the shallow structure comprises of fine‐grained regolith, coarse impact ejecta, and fractured bedrocks
The CE‐4 landing site has a thicker regolith layer (~11 m) compared with the CE‐3, hinting at a longer weathering history
A lower abundance of ilmenite and rocks in the regolith at the CE‐4 site allows 2.85 times the penetration depth compared with CE‐3 site
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