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991.
为解决两端固定支撑弹性梁解的存在性及唯一性问题,运用Leray-Schauder延拓定理,研究一类非线性四阶常微分方程边值问题,当非线性项满足适当至多增长性条件时,得到解的存在性结果.进一步,当非线性项满足Lipschitz条件时,得到解的唯一性结果. 相似文献
992.
993.
该文研究了振荡Robin混合边值齐次化问题解的收敛率.该工作的困难之处在于Robin边值上出现的振荡因子以及边界交叉项的处理.该文利用对偶方法巧妙得对振荡积分进行了估计.文中建立了解的H1和L2收敛率,所得结果明显地依赖于维数.该文可以视为将对偶方法和光滑算子,延拓到处理振荡Robin混合边值问题的情形. 相似文献
994.
Yi Ding Yan Wu Ying Tian Yuzeng Xu Minna Hou Bo Zhou Jingshan Luo Guofu Hou Ying Zhao Xiaodan Zhang 《Journal of Energy Chemistry》2021,(7):48-54
Guanidinium (GA) cations are intentionally introduced in MAPbl3 perovskite by considering its potential capability of stabilizing the material through plenty of... 相似文献
995.
Ya Wang Sinan Zhao Tao Guo Li Li Tantan Li Anqi Wang Dandan Zhang Yanlei Wang Yi Sun 《Molecules (Basel, Switzerland)》2022,27(1)
A novel hybrid PKS–NRPS alkaloid, xylarialoid A (1), containing a 13-membered macrocyclic moiety and [5,5,6] fused tricarbocyclic rings, together with ten known cytochalasins (2–11), was isolated from a plant-derived endophytic fungus, Xylaria arbuscula. The chemical structures of all compounds were elucidated using 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculation. Compounds 1–3 and 10 exhibited significant antitumor activities against A549 and Hep G2 cell lines, with IC50 values of 3.6–19.6 μM. In addition, compound 1 showed potent anti-inflammatory activity against LPS-induced nitric oxide (NO) production in macrophage RAW 264.7 cells (IC50, 6.6 μM). 相似文献
996.
Mengdie Gong Mingyan Tu Hongxia Sun Lu Li Lili Zhu Honglin Li Zhenjiang Zhao Shiliang Li 《Molecules (Basel, Switzerland)》2022,27(1)
Huntington’s disease (HD) is a rare single-gene neurodegenerative disease, which can only be treated symptomatically. Currently, there are no approved drugs for HD on the market. Studies have found that MAPK11 can serve as a potential therapeutic target for HD. Regrettably, no MAPK11 small molecule inhibitors have been approved at present. This paper presents three series of compounds that were designed and synthesized based on the structure of skepinone-L, a known MAPK14 inhibitor. Among the synthesized compounds, 13a and 13b, with IC50 values of 6.40 nM and 4.20 nM, respectively, displayed the best inhibitory activities against MAPK11. Furthermore, the structure–activity relationship (SAR) is discussed in detail, which is constructive in optimizing the MAPK11 inhibitors for better activity and effect against HD. 相似文献
997.
无水AlCl3催化氯苯胺与丙烯腈的加成反应 总被引:6,自引:0,他引:6
报道了无水AlCl3催化邻、间、对氯苯胺三种异构体与丙烯腈发生催化加成反应生成相应的N_氰乙基邻氯苯胺、N_氰乙基间氯苯胺、N_氰乙基对氯苯胺和N,N_二氰乙基邻氯苯胺、N,N_二氰乙基间氯苯胺、N,N_二氰乙基对氯苯胺。结果表明,AlCl3是一种对该类反应具有高催化活性的催化剂。在较低的温度下,用3%~10%(占氯代苯胺的摩尔百分数,以下同)的AlCl3,主要获得单氰乙基产物,最高收率为88%~92%;在较高的温度下,用30%~100%的AlCl,主要获得二氰乙基产物,最高收率为76%~89%。 相似文献
998.
To expose the statistical properties of the degenerated spectrum, with the aid of the random matrix theory,a possible form of the NNS distribution function of the degenerate spectrum was proposed by providing a solution in terms of the same-degeneracy case. The results indicate that the target spectrum is transformed into two sub-spectra: a random one and a regular one, and that the repulsion level of the regular spectrum is also decreased. 相似文献
999.
Runming Wang Jasper Fuk-Woo Chan Suyu Wang Hongyan Li Jiajia Zhao Tiffany Ka-Yan Ip Zhong Zuo Kwok-Yung Yuen Shuofeng Yuan Hongzhe Sun 《Chemical science》2022,13(8):2238
The emergence of SARS-CoV-2 variants of concern compromises vaccine efficacy and emphasizes the need for further development of anti-SARS-CoV-2 therapeutics, in particular orally administered take-home therapies. Cocktail therapy has shown great promise in the treatment of viral infection. Herein, we reported the potent preclinical anti-SARS-CoV-2 efficacy of a cocktail therapy consisting of clinically used drugs, e.g. colloidal bismuth subcitrate (CBS) or bismuth subsalicylate (BSS), and N-acetyl-l-cysteine (NAC). Oral administration of the cocktail reduced viral loads in the lung and ameliorated virus-induced pneumonia in a hamster infection model. The mechanistic studies showed that NAC prevented the hydrolysis of bismuth drugs at gastric pH via the formation of the stable component [Bi(NAC)3], and optimized the pharmacokinetics profile of CBS in vivo. Combination of bismuth drugs with NAC suppressed the replication of a panel of medically important coronaviruses including Middle East respiratory syndrome-related coronavirus (MERS-CoV), Human coronavirus 229E (HCoV-229E) and SARS-CoV-2 Alpha variant (B.1.1.7) with broad-spectrum inhibitory activities towards key viral cysteine enzymes/proteases including papain-like protease (PLpro), main protease (Mpro), helicase (Hel) and angiotensin-converting enzyme 2 (ACE2). Importantly, our study offered a potential at-home treatment for combating SARS-CoV-2 and future coronavirus infections.A cocktail therapy comprising bismuth drugs and N-acetyl-l-cysteine is reported to suppress the replication of SARS-CoV-2 via the oral route. The broad-spectrum inhibitory activities of the combination upon key viral cysteine enzymes are verified. 相似文献
1000.
Dingxuan Ma Huimin Zhao Fan Cao Huihui Zhao Jixin Li Lei Wang Kang Liu 《Chemical science》2022,13(8):2385
Aqueous rechargeable zinc-ion batteries (ZIBs) provide high theoretical capacity, operational safety, low-cost and environmental friendliness for large-scale energy storage and wearable electronic devices, but their future development is plagued by low capacity and poor cycle life due to the lack of suitable cathode materials. In this work, a covalent organic framework (Tp-PTO-COF) with multiple carbonyl active sites is synthesized and successfully introduced in aqueous rechargeable ZIBs for the first time. Tp-PTO-COF delivers high specific capacities of 301.4 and 192.8 mA h g−1 at current densities of 0.2 and 5 A g−1, respectively, along with long-term durability and flat charge–discharge plateaus. The remarkable electrochemical performance is attributed to the abundance of nucleophilic carbonyl active sites, well defined porous structure and inherent chemical stability of Tp-PTO-COF. Moreover, the structural evolution and Zn2+ ion intercalation mechanism are discussed and revealed by the experimental analysis and density functional theory calculations. These results highlight a new avenue to develop organic cathode materials for high performance and sustainable aqueous rechargeable ZIBs.A covalent organic framework (Tp-PTO-COF) with carbonyl active sites was proposed as a novel cathode material and successfully applied in aqueous rechargeable zinc-ion batteries (ZIBs). 相似文献