Beampattern Synthesis for Frequency Diverse Array Based on Time-Modulated Double Parameters Approach

Abstract The basic frequency diverse array (FDA) using linearly increasing frequency increments generates a range-angle dependent beampattern. However, it is coupled in range and angle dimensions and is also periodic in range and time, making its applications limited. In this paper, a novel FDA beampattern synthesis approach is proposed utilizing the time-modulated double parameters based on the chaos sequence. The chirp signal mechanism is used instead of the single-frequency signal mechanism. Meanwhile, the multi-carrier architecture is used for range-angle decoupling. Satisfactory time-invariant range-angle beampattern can be synthesized for both single and multiple targets locations. Simulation results show the effectiveness of the proposed FDA scheme. Furthermore, comparative study with the existing technology indicates that the proposed approach can provide better performance in spatial focusing and side-lobe suppressing.</div

Highly Selective Anion Exchange Membrane Based on Quaternized Poly(triphenyl piperidine) for the Vanadium Redox Flow Battery

Vanadium redox flow batteries (VRFBs) have attracted great attention recently owing to the increasing supply of intermittent renewable energies. However, VRFBs usually suffer from serious vanadium ion crossover and high cost when perfluorinated membranes are employed as the separator. In this study, a highly selective anion exchange membrane (AEM) is synthesized from the aryl ether-free poly­(terphenyl piperidine) (PTP). Using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTMA-Cl) as the quaternization reagent, not only are the piperidinium cations formed in the PTP main chain, but also the side-chain quaternary ammonium cation and hydroxyl group are introduced into the PTP backbone. Compared with pure PTP-TFA and methyl quaternized PTP (PTP-Me) membranes, the obtained hydroxypropyltrimethyl ammonium grafted poly­(terphenyl piperidinium) (PTP-CHPTMA) membrane exhibits high H+ permeability (1.82 × 10–5 cm2 min–1) and low area resistance (0.35 Ω cm2) mainly due to the presence of the hydrophilic hydroxyl group. Owing to the electrostatic repulsion effect of main-chain piperidinium and side-chain quaternary ammonium cations to vanadium ions, the PTP-CHPTMA membrane achieves a low vanadium ion permeability (1.21 × 10–8 cm2 min–1). Consequently, the PTP-CHPTMA membrane reaches 2 orders of magnitude higher ion selectivity than Nafion 115. The assembled single VRFB with PTP-CHPTMA possesses high Coulombic efficiencies of close to 100% at 60–160 mA cm–2 and higher energy efficiencies than the cell with Nafion 115. The self-discharge duration of the cell with PTP-CHPTMA (381 h) is nearly 4.5 times longer than that of Nafion 115 (86 h). Meanwhile, the VRFB based on PTP-CHPTMA displays excellent cycle stability and discharge capacity retention over 580 charge–discharge cycles at 100 mA cm–2

Total Synthesis of Aplysiasecosterol A

Aplysiasecosterol A (1) is a structurally unusual 9,11-secosteroid isolated from the sea hare Aplysia kurodai. We have accomplished the first and asymmetric total synthesis of 1 in a convergent fashion. The left-hand segment bearing three adjacent stereocenters was constructed through desymmetrizing reduction, ketalization, and radical cyclization. A strategy of asymmetric 2-bromoallylation followed by spontaneous desymmetrizing lactolization enabled a more expeditious access to this segment. The right-hand segment was prepared through two different approaches: one featuring Myers alkylation and Suzuki–Miyaura coupling and the other relying upon Aggarwal lithiation–borylation and Zweifel–Evans olefination. The two fragments were coupled by a Reformatsky type reaction. The three consecutive stereocenters embedded in the central domain of 1 were generated by an iron-mediated, hydrogen atom transfer based radical cyclization reaction

Total Synthesis of Aplysiasecosterol A

Aplysiasecosterol A (<b>1</b>) is a structurally unusual 9,11-secosteroid isolated from the sea hare Aplysia kurodai. We have accomplished the first and asymmetric total synthesis of <b>1</b> in a convergent fashion. The left-hand segment bearing three adjacent stereocenters was constructed through desymmetrizing reduction, ketalization, and radical cyclization. A strategy of asymmetric 2-bromoallylation followed by spontaneous desymmetrizing lactolization enabled a more expeditious access to this segment. The right-hand segment was prepared through two different approaches: one featuring Myers alkylation and Suzuki–Miyaura coupling and the other relying upon Aggarwal lithiation–borylation and Zweifel–Evans olefination. The two fragments were coupled by a Reformatsky type reaction. The three consecutive stereocenters embedded in the central domain of <b>1</b> were generated by an iron-mediated, hydrogen atom transfer based radical cyclization reaction

Iron-Catalyzed Regioselective Reductive Fluoroalkylalkenylation of Unactivated Alkenes

The example of iron-catalyzed reductive fluoroalkylalkenylation of unactivated alkenes has been disclosed, affording the stereodefined homoallylic fluoroalkanes with high efficiency and regioselectivity. This three-component cross-electrophile coupling features directing groups free, good functional group tolerance, broad substrate scope, and late-stage difunctionalization of biorelevant molecules. Moreover, this protocol sheds light on the distinct reactivity disparities between fluoroalkyl and nonfluoroalkyl radicals in three-component reductive cross-coupling reactions, highlighting the unique nature of iron/B2pin2 systems

Additional file 1 of Mining key circRNA-associated-ceRNA networks for milk fat metabolism in cows with varying milk fat percentages

Supplementary Material

Table_4_CircRNA screening and ceRNA network construction for milk fat metabolism in dairy cows.XLSX

BackgroundMilk fat is one of the main reference elements for evaluating milk quality and is a primary objective trait in dairy cattle breeding. In recent years, circular RNAs (circRNAs) have been found to play crucial roles in many biological processes. However, the function and expression profiles of circRNAs in milk fat synthesis in cows are not completely understood. We performed RNA sequencing to analyze the genome-wide expression of circRNA transcripts in bovine mammary epithelial cells (BMECs) from cows with extreme differences in milk fat percentage. We identified candidate differential circRNAs associated with milk fat metabolism using functional enrichment analysis and constructed a lipid metabolism-related competing endogenous RNA (ceRNA) interactive regulatory network.ResultsA total of 290 circRNAs were significantly differentially expressed (DE-circRNAs) in high milk fat percentage (HMF) cows compared to that in low milk fat percentage (LMF) cows. Of the 290 circRNAs, 142 were significantly upregulated and 148 were significantly downregulated. Enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) identified four DE-circRNAs (circ_0001122, circ_0007367, circ_0018269, and circ_0015179) that potentially regulate milk fat metabolism. Among them, circ_0001122, circ_0007367, and circ_0015179 had relatively high expression levels in cow mammary gland tissue compared to other tissues (heart, liver, kidney, uterus, ovaries, and small intestine) of cows. The regulatory networks circ_0001122:miR-12043:LIPG, circ_0007367:miR-331-3p:CIDEA/PML, and circ_0018269:miR-11989:RORC/HPX are potential networks to explore the mechanism of milk fat regulation.ConclusionsThese results reveal the possible role of circRNAs in milk fat metabolism in dairy cows. Several important circRNAs and ceRNAs affecting milk fat synthesis were identified, providing insights into the complex biology of milk fat synthesis as well as a novel theoretical perspective for future research on lactation, milk quality, and breed improvement in dairy cows.</p

Table_3_CircRNA screening and ceRNA network construction for milk fat metabolism in dairy cows.XLSX

BackgroundMilk fat is one of the main reference elements for evaluating milk quality and is a primary objective trait in dairy cattle breeding. In recent years, circular RNAs (circRNAs) have been found to play crucial roles in many biological processes. However, the function and expression profiles of circRNAs in milk fat synthesis in cows are not completely understood. We performed RNA sequencing to analyze the genome-wide expression of circRNA transcripts in bovine mammary epithelial cells (BMECs) from cows with extreme differences in milk fat percentage. We identified candidate differential circRNAs associated with milk fat metabolism using functional enrichment analysis and constructed a lipid metabolism-related competing endogenous RNA (ceRNA) interactive regulatory network.ResultsA total of 290 circRNAs were significantly differentially expressed (DE-circRNAs) in high milk fat percentage (HMF) cows compared to that in low milk fat percentage (LMF) cows. Of the 290 circRNAs, 142 were significantly upregulated and 148 were significantly downregulated. Enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) identified four DE-circRNAs (circ_0001122, circ_0007367, circ_0018269, and circ_0015179) that potentially regulate milk fat metabolism. Among them, circ_0001122, circ_0007367, and circ_0015179 had relatively high expression levels in cow mammary gland tissue compared to other tissues (heart, liver, kidney, uterus, ovaries, and small intestine) of cows. The regulatory networks circ_0001122:miR-12043:LIPG, circ_0007367:miR-331-3p:CIDEA/PML, and circ_0018269:miR-11989:RORC/HPX are potential networks to explore the mechanism of milk fat regulation.ConclusionsThese results reveal the possible role of circRNAs in milk fat metabolism in dairy cows. Several important circRNAs and ceRNAs affecting milk fat synthesis were identified, providing insights into the complex biology of milk fat synthesis as well as a novel theoretical perspective for future research on lactation, milk quality, and breed improvement in dairy cows.</p

Palladium(II)-Catalyzed C–H Bond Activation/C–C Coupling/Intramolecular Tsuji–Trost Reaction Cascade: Facile Access to 2<i>H</i>‑Pyrano­naphtho­quinones

An efficient one-pot synthesis of 2<i>H</i>-pyrano­naphtho­quinone was achieved via a palladium-catalyzed C–H bond activation/C–C bond formation/intramolecular Tsuji–Trost reaction cascade. The unprecedented procedure exhibits excellent functional group tolerance, giving the target naphthoquinones in moderate to good isolated yields (40–88%) under mild reaction conditions. Scalable production of the product can make this reaction a method of choice for the synthesis of 2<i>H</i>-pyrano­naphtho­quinones

Table_5_CircRNA screening and ceRNA network construction for milk fat metabolism in dairy cows.XLSX

BackgroundMilk fat is one of the main reference elements for evaluating milk quality and is a primary objective trait in dairy cattle breeding. In recent years, circular RNAs (circRNAs) have been found to play crucial roles in many biological processes. However, the function and expression profiles of circRNAs in milk fat synthesis in cows are not completely understood. We performed RNA sequencing to analyze the genome-wide expression of circRNA transcripts in bovine mammary epithelial cells (BMECs) from cows with extreme differences in milk fat percentage. We identified candidate differential circRNAs associated with milk fat metabolism using functional enrichment analysis and constructed a lipid metabolism-related competing endogenous RNA (ceRNA) interactive regulatory network.ResultsA total of 290 circRNAs were significantly differentially expressed (DE-circRNAs) in high milk fat percentage (HMF) cows compared to that in low milk fat percentage (LMF) cows. Of the 290 circRNAs, 142 were significantly upregulated and 148 were significantly downregulated. Enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) identified four DE-circRNAs (circ_0001122, circ_0007367, circ_0018269, and circ_0015179) that potentially regulate milk fat metabolism. Among them, circ_0001122, circ_0007367, and circ_0015179 had relatively high expression levels in cow mammary gland tissue compared to other tissues (heart, liver, kidney, uterus, ovaries, and small intestine) of cows. The regulatory networks circ_0001122:miR-12043:LIPG, circ_0007367:miR-331-3p:CIDEA/PML, and circ_0018269:miR-11989:RORC/HPX are potential networks to explore the mechanism of milk fat regulation.ConclusionsThese results reveal the possible role of circRNAs in milk fat metabolism in dairy cows. Several important circRNAs and ceRNAs affecting milk fat synthesis were identified, providing insights into the complex biology of milk fat synthesis as well as a novel theoretical perspective for future research on lactation, milk quality, and breed improvement in dairy cows.</p