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.

Collider signatures for the heavy lepton triplet in the type I+III seesaw mechanism

Abstract: The minimal SU(5) theory augmented by the fermionic adjoint representation restores the coupling constant unification and gives realistic neutrino masses and mixing through the hybrid Type I and Type III seesaw. The crucial prediction of the theory is an SU(2) lepton triplet with the mass below TeV. We study the signature of these heavy leptons at the hadron and lepton colliders. The smoking gun evidence of the theory, as in general seesaw mechanisms, is $\ensuremath{\Delta}L=2$ lepton-number violation through events of a pair of like-sign leptons plus four jets without significant missing energy at hadron colliders. We find that via this unique channel the heavy lepton can be searched for up to a mass of 200 GeV at the Tevatron with $8\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, and up to 450 (700) GeV at the LHC of 14 TeV C.M. energy with $10(100)\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The 7 TeV LHC run of $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ is expected to probe a mass window of 110--200 GeV. We also comment on how to distinguish this theory from other models with similar heavy leptons. Finally, we compare the production rates and angular distributions of heavy leptons in ${e}^{+}{e}^{\ensuremath{-}}$ collisions for various models.

A new triazine functionalized luminescent covalent organic framework for nitroaromatic sensing and CO2 storage

Abstract: A new hexagonally ordered covalent organic framework (COF), TRIPTA has been synthesized using Schiff base condensation reaction between 1,3,5-tris-(4-aminophenyl)triazine (TAPT) and 1,3,5-triformylphloroglucinol (TFP). TRIPTA exhibits high crystallinity, a large BET surface area (609 m2 g−1) and pore volume (0.351 cm3 g−1) and possesses high nitrogen content (14.97%). TRIPTA was found to be highly luminescent when suspended in polar solvents upon irradiation of UV light and can detect various nitroaromatic compounds with good sensitivity by fluorescence quenching at concentrations as low as in the range of 10−8 M. The maximum fluorescence quenching was observed for trinitrophenol (61.7% at 5.46 × 10−7 M) with a Stern–Volmer constant of 2.7 × 106 M−1. The COF also showed excellent CO2 uptake capacity of 57.07 wt% at 273 K and 16.02 wt% at 298 K up to 5 bar pressure, with an initial heat of adsorption (Qst) value 56.77 kJ mol−1.

Head group modulated pH-responsive hydrogel of amino acid-based amphiphiles: entrapment and release of cytochrome c and vitamin B12.

Abstract: The present study describes the rational design and synthesis of amino acid-based amphiphilic hydrogelators, which were systemically fine-tuned at the head group to develop pH-responsive hydrogels. To understand the basic structural requirements of a low molecular weight amphiphilic hydrogelator, 10 analogous amphiphiles based on l-phenylalanine and l-tyrosine with structurally related head group were synthesized. Among them, three with quaternary ammonium substitution at the head group formed transparent hydrogels at room temperature while others were unable to gelate water. To establish correlations between the head group architecture of the gelators and their supramolecular arrangements, a variety of spectroscopic and microscopic techniques were investigated that showed that a balance between hydrophilicity and hydrophobicity is required to achieve hydrogelation. Interestingly, the gelator with tyrosinate in its head group showed remarkable response toward external pH. All hydrogels including the pH-re...