Antioxidant and Proapoptotic Activities of Sclerocarya birrea [(A. Rich.) Hochst.] Methanolic Root Extract on the Hepatocellular Carcinoma Cell Line HepG2

The main goal of this study was to characterize the in vitro antioxidant activity and the apoptotic potential of S. birrea methanolic root extract (MRE). Among four tested extracts, obtained with different solvents, MRE showed the highest content of polyphenols, flavonoids, and tannins together with antioxidant activities tested with superoxide, nitric oxide, ABTS, and beta-carotene bleaching assays. Moreover, the cytotoxic effect of MRE was evaluated on the hepatocarcinoma cell line HepG2. In these cells, MRE treatment induced apoptosis and generated reactive oxygen species (ROS) in dose-dependent manner. The cytotoxic effect promoted by MRE was prevented by pretreatment of HepG2 cells with N-acetyl-L-cysteine (NAC), suggesting that oxidative stress was pivotal in MRE-mediated cell death. Moreover, we showed that the MRE treatment induced the mitochondrial membrane depolarization and the cytochrome c release from mitochondria into the cytosol. It suggests that the apoptosis occurred in a mitochondrial-dependent pathway. Interestingly, MRE showed a sensibly lower cytotoxicity, associated with a low increase of ROS, in normal human dermal fibroblasts compared to HepG2 cells. It is suggested that the methanolic root extract of S. Birrea is able to selectively increase intracellular ROS levels in cancer cells, promoting cell death

Note Technique: estimation de canal dans un contexte Massive MIMO et contamination des symboles pilotes pour différents types d'architecture de récepteur

In this paper we address the problem of channel state information guessing algorithms in the context of massive MIMO systems. We illustrate the problem of pilot contamination in the case where several cells share the same spectrum bandwidth and we calculate the capacity of the system for different receiver architectures: Maximum Ratio Combining, Zero-Forcing, MMSE. The theoretical expressions we obtained are the most accurate ones in the open literature of the field.dans ce papier nous traitons le problème de l'estimation des canaux dans un contexte massive MIMO. Nous illustrons le problème de la contamination des symboles pilotes dans le cas où plusieurs cellules partagent les mêmes bandes de fréquence et nous calculons la capacité du système pour différents types d'architecture de récepteur: Maximum Ratio Combining, Zero-Forcing, MMSE. Les expressions théoriques obtenues sont les plus précises que l'on puisse trouver dans la littérature scientifique

Note Technique: CSI estimation in massive MIMO systems and pilot contamination for MMSE receiver architecture

In this paper we address the problem of channel state information guessing algorithms in the context of massive MIMO systems. We illustrate the problem of pilot contamination in the case where several cells share the same spectrum bandwidth and we calculate the capacity of the system for MMSE receiver. The theoretical expressions we obtained are the most accurate ones in the open literature of the field

Note Technique: CSI estimation in massive MIMO systems and pilot contamination for Zero Forcing receiver architectures

In this paper we address the problem of channel state information guessing algorithms in the context of massive MIMO systems. We illustrate the problem of pilot contamination in the case where several cells share the same spectrum bandwidth and we calculate the capacity of the system for Zero-Forcing receiver. The theoretical expressions we obtained are the most accurate ones in the open literature of the field

Note Technique: CSI estimation in massive MIMO systems and pilot contamination MRC receiver architecture

In this paper we address the problem of channel state information guessing algorithms in the context of massive MIMO systems. We illustrate the problem of pilot contamination in the case where several cells share the same spectrum bandwidth and we calculate the capacity of the system for Maximum Ratio Combining receiver. The theoretical expressions we obtained are the most accurate ones in the open literature of the field