Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Excited state & Catalysis. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Inhibition of Amyloid Fibril Growth by Nanoparticle Coated with Histidine-Based Polymer

Abstract: Amyloid protein fibrillation is responsible for variety of neurological disorders and thus inhibition of fibrillation is a potential therapeutic strategy for these diseases. Recent study shows that nanoparticles can significantly influence the kinetics of amyloid fibrillation, depending on their surface chemistry. Here we demonstrate that amyloid fibril formation can be completely inhibited by nanoparticles coated with histidine-based polymer. We have designed nanoparticles with modular surface chemistry and found that the presence of cationic and anionic surface charge, along with weakly hydrophobic functional groups, is essential in inhibiting the amyloid fibrillation processes. This work shows that the appropriate nanoprobe can be designed for controlling the amyloid fibrillation kinetics and for complete inhibition of fibrillation.

Antimicrobial activity, biocompatibility and hydrogelation ability of dipeptide-based amphiphiles

Abstract: The development of new antibiotics is of increasing importance due to the growing resistance power of microbes against conventional drugs. To this end, cationic peptides are emerging as clinically potent antimicrobial agents. In the present study, we have synthesized six dipeptide-based cationic amphiphiles with different head group structures by varying combinations of L-amino acid residues. These amphiphiles showed remarkable growth inhibiting activity on several Gram-positive (minimum inhibitory concentration (MIC) = 0.1–10 µg/mL) and Gram-negative (MIC = 5–150 µg/mL) bacteria as well as on fungus (MIC = 1–50 µg/mL). The inherent antimicrobial efficacies of these cationic dipeptides were influenced by the head group architecture of the amphiphiles. Encouragingly, these amphiphiles selectively attacked microbial cells, while showing biocompatibility toward mammalian cells. The results show that the rational designing of short peptide-based cationic amphiphiles might serve as a promising strategy in the development of antimicrobial agents with greater cell specificities. In addition, the amphiphiles showed water gelation ability at room temperature. The formation of non-covalent supramolecular networks in gelation was established by microscopic and spectroscopic studies.

Origin of the Spin-Orbital Liquid State in a Nearly J=0 Iridate Ba3ZnIr2O9

Abstract: We show using detailed magnetic and thermodynamic studies and theoretical calculations that the ground state of Ba3ZnIr2O9 is a realization of a novel spin-orbital liquid state. Our results reveal that Ba3ZnIr2O9 with Ir5+ (5d(4)) ions and strong spin-orbit coupling (SOC) arrives very close to the elusive J = 0 state but each Ir ion still possesses a weak moment. Ab initio density functional calculations indicate that this moment is developed due to superexchange, mediated by a strong intradimer hopping mechanism. While the Ir spins within the structural Ir2O9 dimer are expected to form a spin-orbit singlet state (SOS) with no resultant moment, substantial frustration arising from interdimer exchange interactions induce quantum fluctuations in these possible SOS states favoring a spin-orbital liquid phase down to at least 100 mK.