Effect of long chain fatty acids on the memory switching behavior of tetraindolyl derivatives.

Non-volatile memory devices using organic materials have attracted much attention due to their excellent scalability, fast switching speed, low power consumption, low cost etc. Here, we report both volatile as well as non-volatile resistive switching behavior of p-di[3,3'-bis(2-methylindolyl)methane]benzene (Indole2) and its mixture with stearic acid (SA). Previously, we have reported the bipolar resistive switching (BRS) behavior using 1,4-bis(di(1H-indol-3-yl)methyl)benzene (Indole1) molecules under ambient conditions [Langmuir 37 (2021) 4449-4459] and complementary resistive switching (CRS) behavior when the device was exposed to 353 K or higher temperature [Langmuir 38 (2022) 9229-9238]. However, the present study revealed that when the H of -NH group of Indole1 is replaced by -CH3, the resultant Indole2 molecule-based device showed volatile threshold switching behaviour. On the other hand, when Indole2 is mixed with SA at a particular mole fraction, dynamic evolution of an Au/Indole2-SA/ITO device from volatile to non-volatile switching occurred with very good device stability (>285 days), memory window (6.69 × 102), endurance (210 times), data retention (6.8 × 104 s) and device yield of the order of 78.5%. Trap controlled SCLC as well as electric field driven conduction was the key behind the observed switching behaviour of the devices. In the active layer, trap centers due to the SA network may be responsible for non-volatile characteristics of the device. Observed non-volatile switching may be a potential candidate for write once read many (WORM) memory applications in future.

Interaction of a Phospholipid and a Coagulating Protein: Potential Candidate for Bioelectronic Applications.

In the present communication, we have investigated the interaction between a biomembrane component 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and a coagulating protein protamine sulfate (PS) using the Langmuir-Blodgett (LB) technique. The π-A isotherm, π-t characteristics, and analysis of isotherm curves suggested that PS strongly interacted with DOPC, affecting the fluidity of the DOPC layer. Electrical characterization indicates that PS as well as the PS-DOPC film showed resistive switching behavior suitable for Write Once Read Many (WORM) memory application. Trap-controlled space charge-limited conduction (SCLC) was the key mechanism behind such observed switching. The presence of DOPC affected the SCLC process, leading to lowering of threshold voltage (V Th), which is advantageous in terms of lower power consumption.

Helicobacter pylori in humans: Where are we now?

Helicobacter pylori has been associated with colonization of gastro duodenal mucosa of humans from millions of years. The main burden of the disese is in the developing countries, due to overcrowding and poor hygiene. If left untreated it leads to lot of sequlae from minor to sinister diseases over a period of time. The main challenges that remain are prevention of H. pylori-related diseases by effective treatment and screening procedures and development of a vaccine, which can address all these issues including beneficial aspects of H. pylori. The literature pertaining to different aspects of H. pylori were scrutinized from Pubmed. Material on clinical behavior, complications of chronic gastric involvement, and prevention besides role of H. pylori in nongastric diseases and the latest trends of management was collected for research and review. We continue to face many challenges. The prevention of cancer of the stomach, a worst sequlae of H. pylori continues to be a big challenge despite population screening and prevention surveys being underway in many countries. On the other hand continued scientific work has now unfolded involvement of H. pylori in extragastric diseases like cerebrovascular, cardiovascular, idiopathic thrombocytopenia, sideroblastic anemia, mental diseases, and collagen vascular diseases. In contrast, the beneficial effects of H. pylori with respect to allergic diseases and obesity are now clear. Moreover, problem of drug resistance for eradication of H. pylori has arisen for which novel treatments are being tried. Lactobacillus reuteri having anti H. pylori action is emerging as one of the promising treatment.