Anti-proliferation and apoptosis effects of Camellia nitidissima C. W. Chi extract on A549 lung cancer cells

Purpose: To investigate the effect of Camellia nitidissima C. W. Chi extract (CNCE) on apoptosis and proliferation in A549 human lung cancer cells.Methods: Inverted microscope was used to examine morphological changes in A549 cells after exposure to CNCE. Trypan blue staining of living cells was applied to construct the cell growth curve after treatment with varying concentrations of CNCE. The influence of CNCE on cell proliferation, apoptosis and cell cycle were determined by MTT assay. The protein expressions of key apoptosisrelated  enzymes were evaluated by immuno-cytochemical method.Results: CNCE inhibited the growth of A549 lung cancer cells at the concentration range of 20 - 160 μg/mL. Flow cytometry showed that CNCE induced apoptosis in the A549 cells. The proportion of cells in G0/G1-phase increased significantly (p < 0.01), while the proportion of cells in S-phase and G2/Mphase decreased  correspondingly, indicating that the cells were in G0/G1-phase arrest. Cell cycle arrest and apoptosis-inducing effect gradually increased with increase in CNCE concentration. With increasing concentrations of CNCE, there were significant increases in the expressions of caspase-3 (p < 0.05), caspase-8 (p < 0.01) and caspase-9 (p < 0.05), and significant decreases in Ki-67 (p < 0.01) and p21 ras protein (p < 0.01).Conclusion: CNCE exerts significant inhibitory effect on the proliferation of A549 lung cancer cells, and therefore can potentially be developed for the treatment of lung cancer.Keywords: Camellia nitidissima, Antitumor activity, Lung cancer, Apoptosis, Cell cycle arrest, Caspas

Utjecaj otopine u čvrstom stanju i starenja na mikrostrukturu i mehanička svojstva kompozita čestica SiCp/Al-Si-Cu-Mg

The SiC particles (SiCp, mass fraction 30 %) reinforced with the Al-Si-Cu-Mg matrix composite have been prepared using one-way press method, sintering, and hot extrusion. The composite was subjected to solid solution treatment at temperatures of 470 °C, 485 °C, 500 °C, 515 °C, and 530 °C for 4 h. The sample was then subjected to ageing treatment at temperatures of 160 °C and 180 °C during different times after solid solution treatment at 515 °C for 4 h. The microstructure and mechanical properties of the SiCp/Al-Si-Cu-Mg matrix composite under the different ageing and solid solution treatments were tested using SEM and TEM microhardness analysis. The results show that the white granulated metallic compounds of the SiCp/Al-Si-Cu-Mg composite materials, which are formed in the sintering process of composite materials, dissolve back after the solid solution treatment at different temperatures. The higher the solid solution temperature, the more metallic compounds dissolve back. The microhardness of the composites reached maximum after solution treatment at 515 °C for 4 h. Following the ageing treatment and with the prolongation of ageing time, the hardness of the composite material reached “double peak” phenomenon. With the increase in ageing temperature, the hardening speed of the composite material also increased, but at the same time, the hardening ability had reduced. After the ageing treatment, the second phases of the composite are discoid Al5Cu6Mg2. This work is licensed under a Creative Commons Attribution 4.0 International License.Pripravljen je kompozit čestica SiC (SiCp) u masenom udjelom 30 % u matrici Al-Si-Cu-Mg prešanjem, sinteriranjem i ekstrudiranjem. Kompozit je 4 sata bio izložen otapanju u čvrstom stanju pri 470 °C, 485 °C, 500 °C, 515 °C i 530 °C. Nakon toga na uzorak je 4 sata pri 515 °C djelovalo otapanje u čvrstom stanju, a zatim su uzorci starili različito vrijeme pri temperaturama 160 i 180 °C. Mikrostruktura i mehanička svojstva kompozita proučena su tehnikama pretražnom i transmisijskom mikroskopijom te analizom mikrotvrdoće. Pri sinteriranju kompozita SiCp/Al-Si-Cu-Mg nastaje bijeli zrnasti metalni spoj koji se otapa u čvrstu otopinu pri različitim temperaturama. Što je viša temperatura čvrste otopine, više se otopi metalnog spoja. Mikrotvrdoća doseže maksimum pri izlaganju reakcijama u čvrstom stanju pri 515 °C kroz četiri sata. Nakon starenja i s produljenjem starenja tvrdoća materijala pokazuje dvostruki vrh. S povišenjem temperature povećava se brzina očvršćivanja, no istodobno se smanjuje mogućnost očvršćenja. Druga faza kompozita nakon starenja je diskoidni Al5Cu6Mg2. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Using Prospect Theory To Explain The Setting Of The Expected Rate Of Return On Pension Assets

Studies often use earnings management to explain the setting of assumed expected rate of return (ERRs) on pension assets in the defined benefit plans. In this paper, we argue that a manager’s risk attitude toward investment may have an impact on setting ERRs on pension assets. Prospect theory is a theory of decision making under risk and is used to explain firms’ behavior with regard to earnings management. We believe that prospect theory also can be used to explain firms’ setting of ERRs, which critically depends on managers’ expectations regarding risky investment. Empirical evidence shows that prospect theory can explain how firms set their ERRs on pension assets. We find that firms in the high-ERR group are risk-averters; that is, there is a positive relationship between risk and return. On the other hand, firms in the low-ERR group are risk-lovers and have an inverse risk-return relationship. Our findings contribute to the literature by suggesting that managers’ risk attitudes also affect the choice of ERR