7-[4-(5,7-Dimethyl-1,8-naphthyridin-2-yl­oxy)phen­oxy]-2,4-dimethyl-1,8-naphthyridine methanol disolvate

The title compound, C26H22N4O2·2CH3OH, was synthesized and characterized by 1H NMR spectroscopy and X-ray structure analysis. There is one half-mol­ecule in the asymmetric unit with a centre of symmetry located at the centre of the benzene ring. The two bridged naphthyridine ring systems are in an anti­parallel orientation. In the crystal structure, O—H⋯N, C—H⋯O and C—H⋯N inter­actions define the packing

VPRSM Based Decision Tree Classifier

A new approach for inducing decision trees is proposed based on the Variable Precision Rough Set Model. From the rough set theory point of view, in the process of inducing decision trees with evaluations of candidate attributes, some methods based on purity measurements, such as information entropy based methods, emphasize the effect of class distribution. The more unbalanced the class distribution is, the more favorable it is. The rough set based approaches emphasize the effect of certainty. The more certain it is, the better. The criterion for node selection in the new method is based on the measurement of the variable precision explicit regions corresponding to candidate attributes. We compared the presented approach with C4.5 on some data sets from the UCI machine learning repository, which instantiates the feasibility of the proposed method

Autophagy Inhibition Enhances Daunorubicin-Induced Apoptosis in K562 Cells

Anthracycline daunorubicin (DNR) is one of the major antitumor agents widely used in the treatment of myeloid leukemia. Unfortunately, the clinical efficacy of DNR was limited because of its cytotoxity at high dosage. As a novel cytoprotective mechanism for tumor cell to survive under unfavorable conditions, autophagy has been proposed to play a role in drug resistance of tumor cells. Whether DNR can activate to impair the sensitivity of cancer cells remains unknown. Here, we first report that DNR can induce a high level of autophagy, which was associated with the activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Moreover, cell death induced by DNR was greatly enhanced after autophagy inhibition by the pharmacological inhibitor chloroquine (CQ) and siRNAs targeting Atg5 and Atg7, the most important components for the formation of autophagosome. In conclusion, we found that DNR can induce cytoprotective autophagy by activation of ERK in myeloid leukemia cells. Autophagy inhibition thus represents a promising approach to improve the efficacy of DNR in the treatment of patients with myeloid leukemia