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Your search keyword '"Jing, Changcheng"' showing total 159 results
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159 results on '"Jing, Changcheng"'

1. Early dark energy triggered by spacetime dynamics that encodes cosmic radiation-matter transition

Author

Jing, Changcheng, Tian, Shuxun, and Zhu, Zong-Hong

Subjects
General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Early dark energy (EDE), introduced at the epoch of matter-radiation equality to alleviate the Hubble tension, has posed a new coincidence problem: why EDE appears at matter-radiation equality when their physics are completely unrelated? To solve this coincidence problem, we propose a new EDE model based on scalar-tensor gravity with the idea that EDE is triggered by spacetime dynamics that encodes cosmic radiation-matter transition. Our model can induce EDE naturally at matter-radiation equality without unnatural parameter tuning. Compared with other EDE models, a distinguishing feature of ours is that it can also induce a new energy component during cosmic matter-dark energy transition. This is testable with low-redshift observations., Comment: 9 pages, 7 figures, published in Phys. Rev. D

Published
2024
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2. Difluorinated thromboxane A2 reveals crosstalk between platelet activatory and inhibitory pathways by targeting both the TP and IP receptors

Author

Allen, Megan F., primary, Hutchinson, James L., additional, Keith, Michael, additional, Mallah, Shahida, additional, Corey, Robin A., additional, Trory, Justin S., additional, Jing, Changcheng, additional, Fang, Huaquan, additional, Wei, Liang, additional, Bennett, Steven H., additional, Aggarwal, Varinder K., additional, Mundell, Stuart J., additional, and Hers, Ingeborg, additional

Published
2024
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3. Difluorinated thromboxane A2 reveals crosstalk between platelet activatory and inhibitory pathways by targeting both the TP and IP receptors.

Author

Allen, Megan F., Hutchinson, James L., Keith, Michael, Mallah, Shahida, Corey, Robin A., Trory, Justin S., Jing, Changcheng, Fang, Huaquan, Wei, Liang, Bennett, Steven H., Aggarwal, Varinder K., Mundell, Stuart J., and Hers, Ingeborg

Subjects
FLUORESCENCE resonance energy transfer, BLOOD platelet aggregation, BLOOD platelet activation, PROTEIN kinases, BIOLUMINESCENCE
Abstract

Background and Purpose: Thromboxane A2 (TXA2) is a prostanoid produced during platelet activaton, important in enhancing platelet reactivity by activation of TP receptors. However, due to the short half‐life, studying TXA2 signalling is challenging. To enhance our understanding of TP receptor‐mediated platelet biology, we therefore synthesised mono and difluorinated TXA2 analogues and explored their pharmacology on heterologous and endogenously expressed TP receptor function. Experimental Approach: Platelet functional and signalling responses were studied using aggregometry, Ca2+ mobilisation experiments and immunoblotting and compared with an analogue of the TXA2 precursor prostaglandin H2, U46619. Gαq/Gαs receptor signalling was determined using a bioluminescence resonance energy transfer (BRET) assay in a cell line overexpression system. Key Results: BRET studies revealed that F‐TXA2 and F2‐TXA2 promoted receptor‐stimulated TP receptor G‐protein activation similarly to U46619. Unexpectedly, F2‐TXA2 caused reversible aggregation in platelets, whereas F‐TXA2 and U46619 induced sustained aggregation. Blocking the IP receptor switched F2‐TXA2‐mediated reversible aggregation into sustained aggregation. Further BRET studies confirmed F2‐TXA2‐mediated IP receptor activation. F2‐TXA2 rapidly and potently stimulated platelet TP receptor‐mediated protein kinase C/P‐pleckstrin, whereas IP‐mediated protein kinase A/P‐vasodilator‐stimulated phosphoprotein was more delayed. Conclusion and Implications: F‐TXA2 is a close analogue to TXA2 used as a selective tool for TP receptor platelet activation. In contrast, F2‐TXA2 acts on both TP and IP receptors differently over time, resulting in an initial wave of TP receptor‐mediated platelet aggregation followed by IP receptor‐induced reversibility of aggregation. This study reveals the potential difference in the temporal aspects of stimulatory and inhibitory pathways involved in platelet activation. [ABSTRACT FROM AUTHOR]

Published
2024
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6. De Novo Synthesis of Dihydrobenzofurans and Indolines and Its Application to a Modular, Asymmetric Synthesis of Beraprost

Author

Wang, Ze-Shu, primary, Bennett, Steven H., additional, Kicin, Bilal, additional, Jing, Changcheng, additional, Pradeilles, Johan A., additional, Thai, Karen, additional, Smith, James R., additional, Bacoş, P. David, additional, Fasano, Valerio, additional, Saunders, Carla M., additional, and Aggarwal, Varinder K., additional

Published
2023
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12. Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

Author

Wang, Hui, Jing, Changcheng, Noble, Adam, and Aggarwal, Varinder Kumar

Subjects
electrophiles, asymmetric synthesis, 010402 general chemistry, 01 natural sciences, Catalysis, Coupling reaction, Stereospecificity, cross-coupling, Boron, Chemistry, 010405 organic chemistry, Enantioselective synthesis, Minireviews, 1,2-migration, General Chemistry, General Medicine, Combinatorial chemistry, 0104 chemical sciences, Zweifel olefination, boronate complex, Chiral, Boronate Complexes, Electrophile, stereospecific, Minireview
Abstract

The stereospecific 1,2‐migration of boronate complexes is one of the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals to natural products. Typically, 1,2‐migration of boronate complexes is driven by displacement of an α‐leaving group, oxidation of an α‐boryl radical, or electrophilic activation of an alkenyl boronate complex. The aim of this article is to summarize the recent advances in the rapidly expanding field of electrophile‐induced stereospecific 1,2‐migration of groups from boron to sp2 and sp3 carbon centers. It will be shown that three different conceptual approaches can be utilized to enable the 1,2‐migration of boronate complexes: stereospecific Zweifel‐type reactions, catalytic conjunctive coupling reactions, and transition metal‐free sp2–sp3 couplings. A discussion of the reaction scope, mechanistic insights, and synthetic applications of the work described is also presented., Electrophile‐induced stereospecific 1,2‐migration of boronate complexes has been successfully applied in many asymmetric reactions. Typically, the electrophilic species provides the activation required for the boronate complex to undergo the desired migration of a group from boron to the adjacent sp2‐ or sp3‐hybridized carbon. Such activating species range from stoichiometric classical electrophiles to transition metal complexes present in catalytic quantities.

Published
2020
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20. Total Synthesis of Thromboxane B2via a Key Bicyclic Enal Intermediate

Author

Jing, Changcheng and Aggarwal, Varinder K.

Abstract

A 12-step asymmetric synthesis of thromboxane B2(TxB2) from 2,5-dimethoxytetrahydrofuran is described. The synthesis employs our organocatalytic aldol reaction of succinaldehyde to give a key bicyclic enal intermediate. From here, the synthetic strategy involves a conjugate addition of an alkenyl side chain to the bicyclic enal, Baeyer–Villiger oxidation, and a highly Z-selective Wittig olefination of a hemiacetal. Key to success was minimizing redox operations and the manipulation of functional groups in the correct order.

Published
2020
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