Indian Institute of Technology Guwahati

About: Indian Institute of Technology Guwahati is a education organization based out in Guwahati, Assam, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 6933 authors who have published 17102 publications receiving 257351 citations.

Vapor phase sensing of ammonia at the sub-ppm level using a perylene diimide thin film device

Abstract: The fabrication of a two terminal sensor device based on a histidine substituted perylene diimide (PDI-HIS) thin film for the sensitive detection and quantification of ammonia (NH3) vapors by monitoring the changes in its current intensity is reported at room temperature under ambient conditions. The thin film morphological variations of the drop cast PDI-HIS films before and after exposure to NH3 vapors are characterized by FESEM and TEM confirming the diffusion/adsorption of the NH3 vapors. The solution cast PDI-HIS thin film gas sensor device exhibited rapid, highly sensitive and selective vapor phase response towards NH3 with a detection limit as low as 0.56 ppm which is much lower than the maximum permissible limit set for NH3 (25 ppm) for prolonged exposure. Furthermore, control sensing experiments performed using alkyl substituted PDI (PDI-n-octyl) demonstrated that the presence of histidine groups at the imide position of PDI-HIS drastically affects the solid-state aggregation mode as well as redox potential that ultimately enhances the sensing response of the device. The key performance parameters of the device such as sensitivity, response/recovery time, selectivity, recyclability, stability and detection limit demonstrated the protocol as simple, reliable, cost-effective and most efficient in performing NH3 detection under very realistic conditions.

Alpinia: the gold mine of future therapeutics.

Abstract: Since prehistoric era, plant-derived drugs were much preferred due to their less side effects than drugs of synthetic origin. Bioassay-guided selection of active fraction of a plant extract and further isolation and characterization of the pure bioactive compounds are in practice in both academic and industrial research. Zingiberaceae, a medicinally important, ornamental, monocotyledonous family has potential members in the tribe Alpinieae, among which the genus Alpinia is studied under this current review due to its wide range of biomedical applications. The members in the genus possess many bioactive compounds against harmful microbes to deadly diseases like cancer by regulating the different signalling pathway systems. Several compounds have been discovered and found to deliver diversified biological efficacy either in vitro or in vivo against a range of diseases. The chemical profiling of the genus and investigation of crude essential oils and individual bioactive compounds towards the therapeutic importance in various disciplines have been documented in the current review.