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We analyze results for the Boson Peak from the neutron time of flight spectroscopy data on Ge-As-Se, and Raman spectra data on m-TCP and OTP, using a recent mode coupling model that takes into account the coupling of density fluctuations with vibrational modes in presence of defects in the supercooled state. From the experimental results for different materials we observe that for more fragile systems characterized by increasing fragility parameter m, a slower relaxation of the defect-density correlation is needed to give rise to the observed peak in the spectra. In Ref.[5] we have described an extension of the simple mode coupling formalism to include the distinct vibrational modes that develop at low temperatures in the amor- The present analysis demonstrates that the criteria for the appearance of the peak is crucially related to the dynamics of defect densities in the disordered system.In studying the feedback effects on dynamics due to slowly decaying density fluctua-1 tions at supercooled states, the memory function H[φ(t)] is obtained as a functional of the hydrodynamic correlation functions, in the following q independent form,where c 1 and c 2 are dimensionless constants determined in terms of the wave vector integrals due to the mode coupling vertex functions. φ L and φ T are the correlation functions for the longitudinal and transverse sound modes. The function F (t) is expressed give rise to the observed peak in the spectra.We have approximated here through δ relaxation of the defect density by single exponential mode. The full wave vector dependence has to be considered to account the coupling of the structural relaxation to the vibrational modes. The explicit temperature dependence of the peak is not captured in the present model. This can be computed through proper input for the static or thermodynamic properties that appear in the mode coupling integrals. Figure 3, demonstrates the key result of this paper that for more fragile systems δ, inverse of which relates to the defect density correlation, shows a sharper fall with temperature. Also we like to point out here that the temperature range 3 covered for the materials in this paper actually correspond to the part where the fragile glasses starts showing a sharp increase of viscosity on the Angell plot[8] -more fragile the liquid is, more dramatic is the increase giving a higher value for the fragility index m [9,15].

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The upsurge of drug resistant tuberculosis is major health threat globally. To counteract, antimicrobial peptides are being explored as possible alternatives. However, certain limitations of peptide-based drugs such as potential toxicity, high cost and relatively low stability need to be addressed to enhance their clinical applicability. Use of computer predicted short active motifs of AMPs along with nanotechnology could not only overcome the limitations of AMPs but also potentiate their antimicrobial activity. Therefore, present study was proposed to in silico identify short antimicrobial motif (Pep-H) of human neutrophil peptide-1 (HNP-1) and explore its antimycobacterial activity in free form and using nanoparticles-based delivery systems. Based on colony forming unit analysis, motif Pep-H led to killing of more than 90% M. tb in vitro at 10 μg/ml, whereas, similar activity against intracellularly growing M. tb was observed at 5 μg/ml only. Thereafter, chitosan (244 nm) and gold nanoparticles (20 nm) were prepared for Pep-H with both the formulations showing minimal effects on the viability of human monocyte derived macrophages (MDMs) and RBC integrity. The antimycobacterial activity of Pep-H against intracellular mycobacteria was enhanced in both the nanoformulations as evident by significant reduction in CFU (>90%) at 5–10 times lower concentrations than that observed for free Pep-H. Thus, Pep-H is an effective antimycobacterial motif of HNP-1 and its activity is further enhanced by chitosan and gold nanoformulations.

The frequency dependent shear modulus G(omega) for a simple liquid shows strongly stretched behavior and the stretching exponent increases with decrease of temperature. This unconventional behavior was reported earlier in Phys. Rev. Lett. 73, 963 (1994) from experiments on simple liquids. We demonstrate here that this is a feature of the characteristic two-step relaxation process of the self-consistent mode coupling theory of supercooled liquids.

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