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901.
合成了三种分子中分别含有-S-,-SO-,-SO2-基力的羧酸型离子表面活性剂,并研究了它们的表面活性。 相似文献
902.
Jie Lu Zhiqiang Huang Yusheng Liu Huimin Wang Min Qiu Yinghui Qu Wenpeng Yuan 《Molecules (Basel, Switzerland)》2022,27(2)
Flavonoids have important biological activities, such as anti-inflammatory, antibacterial, antioxidant and whitening, which is a potential functional food raw material. However, the biological activity of Fengdan peony flavonoid is not particularly clear. Therefore, in this study, the peony flavonoid was extracted from Fengdan peony seed meal, and the antioxidant, antibacterial and whitening activities of the peony flavonoid were explored. The optimal extraction conditions were methanol concentration of 90%, solid-to-liquid ratio of 1:35 g:mL, temperature of 55 °C and time of 80 min; under these conditions, the yield of Fengdan peony flavonoid could reach 1.205 ± 0.019% (the ratio of the dry mass of rutin to the dry mass of peony seed meal). The clearance of Fengdan peony total flavonoids to 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, hydroxyl radical and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical could reach 75%, 70% and 97%, respectively. Fengdan peony flavonoid could inhibit the growth of the Gram-positive bacteria. The minimal inhibitory concentrations (MICs) of Fengdan peony flavonoid on S. aureus, B. anthracis, B. subtilis and C. perfringens were 0.0293 mg/mL, 0.1172 mg/mL, 0.2344 mg/mL and 7.500 mg/mL, respectively. The inhibition rate of Fengdan peony flavonoid on tyrosinase was 8.53–81.08%. This study intensely illustrated that the antioxidant, whitening and antibacterial activity of Fengdan peony total flavonoids were significant. Fengdan peony total flavonoids have a great possibility of being used as functional food materials. 相似文献
904.
Xinsheng Xu Jianlong Qu Tong Li Zhenzhen Tong Zhen Zhao Zhenhuan Zhou 《Acta Mechanica Solida Sinica》2021,34(6):820-829
In this paper,a local surface nanocrystallization technology is used for thin-walled structures with square cross sections,and an energy absorption device of tw... 相似文献
905.
Hongyan Liu Daokui Qu Fang Xu Zhenjun Du Kai Jia Mingmin Liu 《Entropy (Basel, Switzerland)》2022,24(5)
With the rapid development of robot perception and planning technology, robots are gradually getting rid of fixed fences and working closely with humans in shared workspaces. The safety of human-robot coexistence has become critical. Traditional motion planning methods perform poorly in dynamic environments where obstacles motion is highly uncertain. In this paper, we propose an efficient online trajectory generation method to help manipulator autonomous planning in dynamic environments. Our approach starts with an efficient kinodynamic path search algorithm that considers the links constraints and finds a safe and feasible initial trajectory with minimal control effort and time. To increase the clearance between the trajectory and obstacles and improve the smoothness, a trajectory optimization method using the B-spline convex hull property is adopted to minimize the penalty of collision cost, smoothness, and dynamical feasibility. To avoid the collisions between the links and obstacles and the collisions of the links themselves, a constraint-relaxed links collision avoidance method is developed by solving a quadratic programming problem. Compared with the existing state-of-the-art planning method for dynamic environments and advanced trajectory optimization method, our method can generate a smoother, collision-free trajectory in less time with a higher success rate. Detailed simulation comparison experiments, as well as real-world experiments, are reported to verify the effectiveness of our method. 相似文献
906.
907.
Zhuojia Xu Aihua Qu Hongyu Zhang Weiwei Wang Changlong Hao Meiru Lu Baimei Shi Liguang Xu Maozhong Sun Chuanlai Xu Hua Kuang 《Chemical science》2022,13(22):6642
Parkinson''s disease (PD) is an age-related neurodegenerative disease, and the removal of senescent cells has been proved to be beneficial for improving age-associated pathologies in neurodegeneration disease. In this study, chiral gold nanoparticles (NPs) with different helical directions were synthesized to selectively induce the apoptosis of senescent cells under light illumination. By modifying anti-B2MG and anti-DCR2 antibodies, senescent microglia cells could be cleared by chiral NPs without damaging the activities of normal cells under illumination. Notably, l-P+ NPs exhibited about a 2-fold higher elimination efficiency than d-P− NPs for senescent microglia cells. Mechanistic studies revealed that the clearance of senescent cells was mediated by the activation of the Fas signaling pathway. The in vivo injection of chiral NPs successfully confirmed that the elimination of senescent microglia cells in the brain could further alleviate the symptoms of PD mice in which the alpha-synuclein (α-syn) in cerebrospinal fluid (CFS) decreased from 83.83 ± 4.76 ng mL−1 to 8.66 ± 1.79 ng mL−1 after two months of treatment. Our findings suggest a potential strategy to selectively eliminate senescent cells using chiral nanomaterials and offer a promising strategy for alleviating PD.The apoptosis pathways of senescent microglia cells induced by chiral NPs under the irradiation of 808 nm laser in the brain of PD mice. 相似文献
908.
909.
增强UV-B辐射和多效唑对绿豆光合作用的影响 总被引:1,自引:1,他引:1
使用TPS-1便携式光合仪结合Farquhar和Sharkey的理论测定或计算增强UV-B辐射、多效唑(PP333)及其复合处理幼苗的相关光合指标,并同时测定核酮糖-1,5-二磷酸羧化/加氧酶(Rubisco)含量.发现UV-B辐射降低净光合速率(Pn)、气孔限制值(Ls)和气孔导度(Gs),但使胞间隙CO2浓度(Ci)增加;PP333提高Pn、Gs和Ci,却使Ls下降;与PP333处理相较,UV-B+PP333诱导Pn、Gs和Ci降低,却促进Ls增加;UV-B对Pn、叶肉细胞光合能力(Ao)、表观量子效率(AQY)、羧化效率(dPn/dCi)和Rubisco含量的降低程度大于PP333对上述指标的提高程度,亦大于PP333处理下UV-B对上述指标的抑制程度.结果表明,UV-B降低Pn的主要原因为叶肉细胞光合活性的抑制,而PP333促进Pn及PP333减轻UV-B对Pn的抑制效应主要是通过调节Gs实现的. 相似文献
910.
Ziru Liu Jiameng Qu Fan Ke Haotian Zhang Yiwen Zhang Qian Zhang Qing Li Kaishun Bi Huarong Xu 《Molecules (Basel, Switzerland)》2022,27(9)
The excessive expression of reactive oxygen species is closely connected to many diseases. Considerable studies have demonstrated dandelion as well as its ingredients exhibited antioxidant activity. However, specific material basis reflecting the antioxidant activity has not been comprehensively investigated. In this study, a spectrum–effect relationship study on dandelion between fingerprinting and antioxidant activity was analyzed in detail, while a UHPLC quantification method developed and completely validated for simultaneous determination of active ingredients in dandelion. With the establishment of dandelion fingerprints of different regions, 24 common peaks were characterized. The classic FRAP method and ABTS methods were then used to detect their antioxidant activity. Partial least squares regression analysis, bivariate correlation analysis and grey correlation method were used to accomplish the spectrum–effect relationship. Eventually, the ingredients with antioxidant activity which could be considered as candidate quality markers of dandelion were discovered through spectrum–effect relationship analysis. The six compounds including caftaric acid, chlorogenic acid, caffeic acid, chicoric acid, isochlorogenic acid A, and isochlorogenic acid C were quantitatively determined. The developed UHPLC assay method was accurate, precise, and reliable. The study has elucidated the antioxidant material basis of dandelion and provided a scientific basis for the quality control of dandelion. 相似文献