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An unprecedented in situ SO2-capture cascade triggered by alkyl radicals has been documented herein. Mechanistic investigations suggest that, triggered by alkyl radicals, SO2 was released in situ and subsequently fixed into polycyclic small molecules. A wide range of alkylsulfonyl substituted polycyclic compounds were easily prepared with high yields and good functional group tolerability. [ABSTRACT FROM AUTHOR]

We report an efficient oxidative radical desulfur-fragmentation and reconstruction of enol triflates for the synthesis of α-CF3 ketones. Preliminary mechanistic studies disclosed that oxidative fragmentation to release a CF3 radical from the triflyl group of enol triflate and subsequent addition of the CF3 radical to another enol triflate form the desired α-CF3 ketones. This method provides a new approach to α-CF3 ketones, featuring the utilization of catalytic amount of oxidants, broad substrate scope, and potential to control the regioselectivity. [ABSTRACT FROM AUTHOR]

This paper analyzes the shear performance of prismatic and tapered beams with corrugated steel webs (CSWs) under different layouts of external prestressing based on finite element (FE) simulations. The results show that when the external prestressing tendon distribution is straight, there is no shear stress in the prismatic beam with CSWs, but there is shear stress in the tapered beam with CSWs. Therefore, it is not generally accurate that only the vertical component of the external prestressing force can induce shear stress when calculating the shear stresses caused by external prestressing in the existing design specifications. In theory, it is proven, for the first time, that the axial force and prestressing bending moment generated by external prestressing will generate additional shear stresses, which will cause the shear stress redistribution in tapered beams with CSWs. However, these two factors were not taken into account in existing design specifications, which resulted in a significant error in predicting the shear stress for tapered beams with CSWs when ignoring the contribution of the axial force and prestressing bending moment. Consequently, a unified analytical formula is proposed for predicting the shear stresses caused by an external prestressing force on the CSW, and this formula can be appropriate for both tapered and prismatic beams with CSWs under both straight and bent external prestressing tendons. In addition, this study quantitatively investigates the ratios of shear stresses in the CSWs induced by the vertical and horizontal components of the external prestressing force, and their corresponding bending moments. Finally, the study reveals the factors affecting the distribution of shear stress on beams with CSWs under external prestressing and proves that using the traditional method to calculate the shear stress neglects the shear capacity of the inclined concrete bottom slab will produce a significant error when applied to tapered cases. • The prismatic and tapered beams with corrugated steel webs (CSWs) under external prestressing were analyses. • It is proven that the prestressing bending moment and axial force will generate additional shear stresses. • A unified analytical formula is proposed for predicting the shear stresses caused by external prestressing on the CSWs. • The factors affecting the distribution of shear stress on beams with CSWs under external prestressing were revealed. [ABSTRACT FROM AUTHOR]

This paper presents an efficient and feasible algorithm for the path planning problem of the multiple unmanned aerial vehicles (multi-UAVs) formation in a known and realistic environment. The artificial potential field method updated by the additional control force is used for establishing two models for the single UAV, which are the particle dynamic model and the path planning optimization model. The additional control force can be calculated by using the optimal control method. Furthermore, the multi-UAV path planning model is established by introducing 'virtual velocity rigid body' and 'virtual target point'. Then, the motion states of the lead plane and wingmen are obtained from the path planning model. Finally, the path following process based on the quadrotor helicopter PID controllers is introduced to verify the rationality of the path planning results. The simulation results show that the artificial potential method with the additional control force improved by the optimal control method has a good path planning ability for the single UAV and the all UAVs formation. At the same time, the path planning results are available and the UAVs can basically track the UAV formation. [ABSTRACT FROM AUTHOR]

Sirtuin 1 (SIRT1) overexpression significantly inhibits lipid deposition during yak intramuscular preadipocyte (YIMA) differentiation; however, the regulatory mechanism remains unknown. We elucidated the role of SIRT1 in YIMA differentiation using lentivirus-mediated downregulation technology and conducted mRNA-seq and ChIP-seq assays using H3K9ac antibodies after SIRT1 overexpression in order to reveal SIRT1 targets during YIMA adipogenesis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed in order to identify the functional annotation of common genes. In addition, a potential target of SIRT1 was selected to verify its effects on the differentiation and proliferation of YIMAs. SIRT1 interfered with lipid deposition and promoted YIMA differentiation. In total, 143,518 specific peaks were identified after SIRT1 overexpression, where genes associated with downregulation peaks were enriched in transcription, gene expression, lipid-related processes, and classical lipid-related pathways. The H3K9ac signal in the whole genome promoter region (2 kb upstream and downstream of the transcription start site (TSS)) was weakened, and the peaks were distributed across all gene functional regions. Genes that lost signals in their TSS region or gene body region were enriched in both biological processes and pathways associated with lipogenesis. The ChIP-seq results revealed 714 common differential genes in mRNA-seq, which were enriched in "MAPK signaling", "lipid and atherosclerosis", "mTOR signaling", and "FoxO signaling" pathways. A total of 445 genes were downregulated in both their H3K9ac signals and mRNA expression, and one of their most significantly enriched pathways was FoxO signaling. Nine genes (FBP2, FPGT, HSD17B11, KCNJ15, MAP3K20, SLC5A3, TRIM23, ZCCHC10, and ZMYM1) lost the H3K9ac signal in their TSS regions and had low mRNA expression, and three genes (KCNJ15, TGM3, and TRIM54) had low expression but lost their H3K9ac signal in the gene body region. The interference of TRIM23 significantly inhibited fat deposition during preadipocyte differentiation and promoted cell proliferation by increasing S-phase cell numbers. The present study provides new insights into the molecular mechanism of intramuscular fat content deposition and the epigenetic role of SIRT1 in adipocyte differentiation. [ABSTRACT FROM AUTHOR]

Closing the circle: A versatile and modular method yields various saturated and unsaturated N ‐ heterocyclic carbene precursors from a Tf2O ‐ mediated intramolecular cyclization reaction. A resultant sterically demanding oxazolium salt could be used not only as good intermediate for directly preparing N,N′ ‐ disubstituted imidazolium salts in one step, but also as a precursor of sterically demanding oxazol ‐ 2 ‐ ylidene. [ABSTRACT FROM AUTHOR]