<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

(SoNS) School of Natural Sciences

Mono-benzoxazine monomers based polybenzoxazines suffer from a lower crosslink density and char yield that especially is further diluted by the presence of longer alkylene chain in cardanol (C). In order to improve the crosslink density, char yield and to understand the role of higher aromatic content vs functionality, a series of cardanol-based benzoxazine monomers were synthesised. The amine condensed with cardanol and paraformaldehyde were aniline (a), 4-triphenylmethylaniline (ta), and tetra-aminophenyl methane (tapm) via solventless methodology. The C-a and C-ta are mono-benzoxazines while C-tapm is a tetra-benzoxazine monomer. The monomers were structurally characterised using FT-IR, 1H and 13C NMR spectroscopy and mass spectrometry. The ring opening polymerisation temperature (ROP) of monomers and thermal stability of resins was determined using DSC and TGA while mechanical properties were determined using rheometry. The curing kinetic study using FT-IR and DSC showed C-ta has intermediate curing behaviour between the C-a and C-tapm. The Ea for curing reaction C-a, C-ta and C-tapm was found to be 143, 126 and 70 kJ/mol. The lowest Ea for curing reaction of C-tapm (tetra-benzoxazine) is due to its highest functionality but C-ta (mono-benzoxazine) has lower Ea than C-a which can be accounted to the presence of more reactive sites provided by the additional aromatic rings in the former. It was found that the incorporation of higher aromatic ring in benzoxazine monomers is another route in enhancing the crosslink density besides higher functionality to modulate their properties. © 2016 Elsevier Ltd

Chemistry

Polymer

Role of higher aromatic content in modulating properties of cardanol based benzoxazines

We calculate the k-point generating function of the correlated Jacobi ensemble using supersymmetric methods. We use the result for complex matrices for k=1 to derive a closed-form expression for the eigenvalue density. For real matrices we obtain the density in terms of a twofold integral that we evaluate numerically. For both expressions we find agreement when comparing with Monte Carlo simulations. Relations between these quantities for the Jacobi and the Cauchy–Lorentz ensemble are derived. © 2015, Springer Science+Business Media New York.

World University root node

Physics

Fulltext

Journal of Statistical Physics

The Correlated Jacobi and the Correlated Cauchy–Lorentz Ensembles

Two-dimensional infrared spectroscopy of backbone vibrations maps interactions of natural salmon DNA with its water shell. Fast fluctuations in the 300 fs regime are discerned from quasi-static disorder, establishing the short-range character of electrical interactions.

Optics InfoBase Conference Papers

Hydration of native DNA: Ultrafast structural dynamics and short-range electric fields

We have performed steady state UV-visible absorption and time-resolved fluorescence measurements and computer simulations to explore the cosolvent mole fraction induced changes in structural and dynamical properties of water/dioxane (Diox) and water/tetrahydrofuran (THF) binary mixtures. Diox is a quadrupolar solvent whereas THF is a dipolar one although both are cyclic molecules and represent cycloethers. The focus here is on whether these cycloethers can induce stiffening and transition of water H-bond network structure and, if they do, whether such structural modification differentiates the chemical nature (dipolar or quadrupolar) of the cosolvent molecules. Composition dependent measured fluorescence lifetimes and rotation times of a dissolved dipolar solute (Coumarin 153, C153) suggest cycloether mole-fraction (XTHF/Diox) induced structural transition for both of these aqueous binary mixtures in the 0.1 ≤ XTHF/Diox ≤ 0.2 regime with no specific dependence on the chemical nature. Interestingly, absorption measurements reveal stiffening of water H-bond structure in the presence of both the cycloethers at a nearly equal mole-fraction, XTHF/Diox ∼ 0.05. Measurements near the critical solution temperature or concentration indicate no role for the solution criticality on the anomalous structural changes. Evidences for cycloether aggregation at very dilute concentrations have been found. Simulated radial distribution functions reflect abrupt changes in respective peak heights at those mixture compositions around which fluorescence measurements revealed structural transition. Simulated water coordination numbers (for a dissolved C153) and number of H-bonds also exhibit minima around these cosolvent concentrations. In addition, several dynamic heterogeneity parameters have been simulated for both the mixtures to explore the effects of structural transition and chemical nature of cosolvent on heterogeneous dynamics of these systems. Simulated four-point dynamic susceptibility suggests formation of clusters inducing local heterogeneity in the solution structure. © 2016 AIP Publishing LLC.

Journal of Chemical Physics

Structural anomaly and dynamic heterogeneity in cycloether/water binary mixtures: Signatures from composition dependent dynamic fluorescence measurements and computer simulations

Recently, deviations in flavor observables of B→D(∗)τν have been shown between the predictions in the Standard Model and the experimental results reported by BABAR, Belle, and LHCb collaborations. One of the solutions to this anomaly is obtained in a class of leptoquark model with a scalar leptoquark boson S1, which is a SU(3)c triplet and SU(2)L singlet particle with -1/3 hypercharge interacting with a quark-lepton pair. With well-adjusted couplings, this model can explain the anomaly and be compatible with all flavor constraints. In such a case, the S1 boson can be pair-produced at CERN's Large Hadron Collider (LHC) and subsequently decay as S1∗→tτ, bντ, and cτ. This paper explores the current 8 and 13 TeV constraints, as well as the detailed prospects at 14 TeV, of this flavor-motivated S1 model. From the current available 8 and 13 TeV LHC searches, we obtain constraints on the S1 boson mass for MS1<400-640 GeV depending on values of the leptoquark couplings to fermions. Then we study future prospects for this scenario at the 14 TeV LHC using detailed cut analyses and evaluate exclusion and discovery potentials for the flavor-motivated S1 leptoquark model from searches for the (bν)(bν) and (cτ)(cτ) final states. In the latter case, we consider several scenarios for the identification of charm jets. As a result, we find that the S1 leptoquark origin of the B→D(∗)τν anomaly can be probed with MS1600/800 GeV at the 14 TeV LHC with L=300/3000 fb-1 of accumulated data. One can also see that the 14 TeV LHC run II with L=300 fb-1 can exclude the S1 leptoquark boson up to MS1∼0.8 TeV at 95% confidence level, whereas a future 14 TeV LHC with L=3000 fb-1 data has a potential to discover the S1 leptoquark boson with its mass up to MS1∼1.1 TeV with over 5σ significance, from the (bν)(bν) and/or (cτ)(cτ) searches. © 2016 American Physical Society.

Physical Review D

LHC constraints and prospects for S1 scalar leptoquark explaining the B →d (∗)τ ν anomaly LHC CONSTRAINTS and PROSPECTS for S1 ... DUMONT, NISHIWAKI, and WATANABE

DNA oligomers are studied at 0% and 92% relative humidity, corresponding to N&lt;2 and N&gt;20 water molecules per base pair. Two-dimensional (2D) infrared spectroscopy of DNA backbone modes between 920 and 1120 cm,-1 maps fluctuating interactions at the DNA surface. At both hydration levels, a frequency fluctuation correlation function with a 300 fs decay and a slow decay beyond 10 ps is derived from the 2D lineshapes. The fast component reflects motions of DNA helix, counterions, and water shell. Its higher amplitude at high hydration level reveals a significant contribution of water to the fluctuating forces. The slow component reflects disorder-induced inhomogeneous broadening. © 2015 Author(s).

Structural Dynamics

Ultrafast vibrational dynamics of the DNA backbone at different hydration levels mapped by two-dimensional infrared spectroscopy

We report the thermodynamic properties, magnetic ground state and microscopic magnetic model of the spin-1 frustrated antiferromagnet Li2NiW2O8, showing successive transitions at TN1≃18 K and TN2≃12.5 K in zero field. Nuclear magnetic resonance and neutron diffraction reveal collinear and commensurate magnetic order with the propagation vector k=(12,0,12) below TN2. The ordered moment of 1.8$\mu$B at 1.5 K is directed along [0.89(9),-0.10(5),-0.49(6)] and matches the magnetic easy axis of spin-1Ni2+ ions, which is determined by the scissor-like distortion of the NiO6 octahedra. Incommensurate magnetic order, presumably of spin-density-wave type, is observed in the region between TN2 and TN1. Density-functional band-structure calculations put forward a three-dimensional spin lattice with spin-1 chains running along the [011] direction and stacked on a spatially anisotropic triangular lattice in the ab plane. We show that the collinear magnetic order in Li2NiW2O8 is incompatible with the triangular lattice geometry and thus driven by a pronounced easy-axis single-ion anisotropy of Ni2+.

Physical Review B

Commensurate and incommensurate magnetic order in spin-1 chains stacked on the triangular lattice in Li2NiW2 O8

Abstract: Search for the bottom squarks (sbottoms) at the Large Hadron Collider (LHC) has recently assumed a heightened focus in the hunt for Supersymmetry (SUSY). The popular framework of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) could conceive a naturally light sbottom which can easily be consistent with available constraints from the experiments at the LHC. Phenomenology of such sbottoms could in principle be as striking as that for a light top squark (stop) thanks to a rather nontrivial neutralino sector (with appreciable mixing among the neutral higgsinos and the singlino) that the scenario gives rise to. Nonetheless, finding such sbottoms would require a moderately large volume of data (∼300 fb−1) at the 13 TeV run of the LHC. A multi-channel analysis establishing a generic depletion of events in the usual 2b-jets + [InlineMediaObject not available: see fulltext.]T final state while registering, in conjunction, characteristically significant rates in various multi-lepton final states accompanied by b-jets might point not only to the presence of light sbottom(s) but could also shed crucial light on their compositions and the (singlino) nature of the lightest SUSY particle (LSP).

Journal of High Energy Physics

Sbottoms of natural NMSSM at the LHC

Topological properties of chemical library networks, such as the average clustering coefficient, average path length, and existence of hubs, can serve as indicators to describe the inherent complexities of chemical libraries. We have used Diversity-Oriented Synthesis (DOS) and Focussed Libraries to investigate the appearance of scale-free properties and absence of small-world behavior in chemical libraries. DOS aims to elicit structural complexity in small compounds with respect to skeleton, functional groups, appendages and stereochemistry. Complexity here indicates incorporation of sp 3 carbons, hydrogen bond acceptors and donors in the molecule. Biological studies have shown how structural complexity enhances the interaction of molecules with complex biological macromolecules. In contrast, Focussed Libraries concentrate on specific scaffolds against a specific biological target. We have quantified the diversity in several DOS and Focussed Libraries based on properties of similarity and dissimilarity threshold networks formed from them. Similarity and dissimilarity networks were generated from diverse chemical libraries at various Tanimoto similarity coefficients (t c) using FP2 and MACCS fingerprints. The dissimilarity networks at very low t c threshold led to the absence of small-world behaviors, as evidenced by low average clustering coefficient and high average path length in comparison to Erdös–Renyi networks. Dissimilarity networks exhibit scale free topology as evidenced by a power law degree distribution. The similarity networks at high t c threshold have shown high clustering coefficients and low average path lengths, without the appearance of hubs. Combining dissimilarity and similarity threshold graphs revealed assortative and dissortative behaviors in the DOS libraries, leading to the conclusion that the vertices of the dissimilarity communities are more likely to share similarity edges, but it is quite unlikely for the vertices in a similarity community to share dissimilarity edges. We propose a simple and convenient diversity quantification tool, QuaLDI (Quantitative Library Diversity Index) to quantify the diversity in DOS and Focussed libraries. We anticipate that these topological properties can be used as descriptors to quantify the diversity in chemical libraries before proceeding for synthesis. © 2016, Springer International Publishing Switzerland.

Mathematics

Journal of Mathematical Chemistry

Investigation of similarity and diversity threshold networks generated from diversity-oriented and focused chemical libraries

Ternary lipid mixtures incorporating cholesterol are well-known to phase separate into liquid-ordered (Lo) and liquid-disordered (Ld) phases. In multilayers of these systems, the laterally phase separated domains register in columnar structures with different bilayer periodicities, resulting in hydrophobic mismatch energies at the domain boundaries. In this paper, we demonstrate via synchrotron-based X-ray diffraction measurements that the system relieves the hydrophobic mismatch at the domain boundaries by absorbing larger amounts of inter-bilayer water into the Ld phase with lower d-spacing as the relative humidity approaches 100\%. The lamellar repeat distance of the Ld phase swells by an extra 4 Å, well beyond the equilibrium spacing predicted by the inter-bilayer forces. This anomalous swelling is caused by the hydrophobic mismatch energy at the domain boundaries, which produces a surprisingly long-range effect. We also demonstrate that the d-spacings of the lipid multilayers at 100\% relative humidity do not change when bulk water begins to condense on the sample. © the Owner Societies 2016.