Recent Advances in Halide Perovskite Resistive Switching Memory Devices: A Transformation from Lead-Based to Lead-Free Perovskites.

Due to their remarkable electrical and light absorption characteristics, hybrid organic-inorganic perovskites have recently gained popularity in several applications such as optoelectronics, lasers, and light-emitting diodes. Through this, there has recently been an increase in the use of halide perovskites (HPs) in resistive switching (RS) devices. However, lead-based (Pb-based) perovskites are notorious for being unstable and harmful to the environment. As a result, lead-free (Pb-free) perovskite alternatives are being investigated in achieving the long-term and sustainable use of RS devices. This work describes the characteristics of Pb-based and Pb-free perovskite RS devices. It also presents the recent advancements of HP RS devices, including the selection strategies of perovskite structures. In terms of resistive qualities, the directions of both HPs appear to be identical. Following that, the possible impact of switching from Pb-based to Pb-free HPs is examined to determine the requirement in RS devices. Finally, this work discusses the opportunities and challenges of HP RS devices in creating a stable, efficient, and sustainable memory storage technology.

Bile Acid Synthesis Disorder Masquerading as Intractable Vitamin D-Deficiency Rickets.

Vitamin D-deficiency rickets, not responding to large treatment doses of oral vitamin D, suggest rare receptor mutations, malabsorption, or hepatobiliary dysfunction. We present a set of twins of Hispanic origin who presented with refractory vitamin D-deficiency rickets and failure to thrive (FTT) at 6 months of age. On follow-up, mild elevations in serum alanine transaminases and normal aspartate aminotransferase were noted. Subsequently, patients manifested fat-soluble vitamin deficiencies. More targeted evaluations revealed a diagnosis of 3ß-hydroxy-Δ 5-C27-steroid oxidoreductase deficiency. Treatment with oral bile acid replacement with cholic acid resolved rickets and promoted weight gain. Bile acid synthesis disorders should be suspected in refractory rickets in infancy, particularly in a clinical setting of FTT, even in the absence of substantial abnormalities in liver-function tests.

Synthesis of 2-methyl N10-substituted acridones as selective inhibitors of multidrug resistance (MDR) associated protein in cancer cells.

A series of N10-substituted-2-methyl acridone derivatives are synthesized and are examined for its ability to reverse P-glycoprotein (P-gp) mediated multidrug resistance (MDR) in breast cancer cell lines MCF-7 and MCF-7/Adr. The structural requirement of in-vitro anti-cancer and reversal of drug resistance are studied. The results showed that compound 16 with four carbon spacer exhibited promising in-vitro anti-cancer and reversal of drug resistance in comparison to the other analogues.