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再生混凝土 1

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Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing the production of reactive oxygen species

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《医学前沿（英文）》 2018年第12卷第3期页码 289-300 doi: 10.1007/s11684-017-0550-7

摘要：

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag⁺) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag⁺and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag⁺ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10⁻⁶ and 10⁻⁵ mol/L Ag⁺ at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5–60 min after exposure to Ag⁺. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10⁻⁶ and 10⁻⁵ mol/L Ag⁺, with 10⁻⁵ mol/L Ag⁺ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag⁺ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag⁺ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.

关键词： ionic silver human keratinocyte cell proliferation reactive oxygen species active oxygen scavenger NAC

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Relationship between reactive oxygen species and sodium-selenite-induced DNA damage in HepG2 cells

ZOU Yunfeng, NIU Piye, GONG Zhiyong, YANG Jin, YUAN Jing, WU Tangchun, CHEN Xuemin

《医学前沿（英文）》 2007年第1卷第3期页码 327-332 doi: 10.1007/s11684-007-0063-x

摘要： Selenium compounds, as an effective chemopreventive agent, can induce apoptosis in tumor cells. Reactive oxygen species (ROS) are important mediators in apoptosis induced by various stimuli, which include chemopreventive agents. In this study, we investigated the relationship between ROS and the levels of DNA damage induced by selenite in HepG2 cells. After HepG2 cells were treated with selenite, there was a dose-dependent decrease in cell viability. The levels of ROS induced by selenite were measured by 2′, 7′-dichlorofluorescein diacetate (DCFH-DA) fluorescence, which shows a dose- and time-dependent increase in HepG2 cells. The levels of DNA damage in HepG2 increased in all cells treated with an increasing dose of selenite at 0, 2.5, 5, 10, and 20 μmol/L. N-acetylcysteine (NAC), a known antioxidant, increased cell viability and decreased ROS generation. Moreover, NAC effectively blocked DNA damage induced by selenite. These results revealed that ROS might play an important role in selenite-induced DNA damage that can be reduced by NAC treatment.

关键词： NAC N-acetylcysteine DNA fluorescence relationship

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再生与原生混凝土结构构件统一设计理论的基础问题 Article

肖建庄, 张凯建, 丁陶, 张青天, 肖绪文

《工程（英文）》 2023年第29卷第10期页码 188-197 doi: 10.1016/j.eng.2023.03.017

摘要：

再生混凝土作为一种低碳混凝土，成为近20年来国内外的研究热点，但是目前再生混凝土结构的设计仍是一个挑战。本文从原生与再生混凝土结构构件统一设计的新需求出发，剖析了两者统一设计的必要性，并从强度取值、受压本构关系以及结构构件设计方法等方面进行了深入论证。分析发现，再生混凝土的强度变异系数总体上高于原生混凝土，再生混凝土的抗压强度及抗拉强度代表值的定义和取值方法与原生混凝土一致；原生与再生混凝土的单轴受压本构关系具有统一的数学表达形式，但与原生混凝土相比，再生混凝土弹性模量降低、脆性增加。最后，提出了再生混凝土构件安全可靠度调整系数，实现了再生与原生混凝土构件承载力设计公式的统一，并从概念设计和构造措施上，论证了考虑时变强度与钢筋锈蚀等影响的时变可靠度统一的可行性。本文的工作，丰富和发展了混凝土结构基本理论。

关键词：再生混凝土原生混凝土强度取值本构关系可靠度统一设计方法