A series of glasses were prepared by rapid melt quench method in the glass system (65 − x)[(Ba 0.6 Sr 0.4)TiO 3 ]-30[2SiO 2-B 2 O 3 ]-5[K 2 O]-x[La 2 O 3 ] (x = 0, 1, 2, 5 and 10). X-ray diffraction of glass samples were carried to check its amorphousity. Density of glass samples were measured using Archimedes principle. The refractive index of these glass samples lies between 2.39 to 2.80. Optical properties of these glass samples were studied using Infrared (IR) and Raman spectroscopic techniques. IR measurements were done over a continous spectral range 450-4000 cm-1 to study their stucture networking systematically while Raman spectra were recorded over a continous spectral range 200-2000 cm-1. IR spectra of all glass samples showed number of absorption peaks. These absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO 3. The Raman spectra of all glass samples exhibited different spectral bands and intensity of these bands changes drastically. The network structure of these glass samples is mainly based on BO 3 and BO 4 units placed in different structural groups.

The recent emergence of hypervirulent clinical variants of Klebsiella pneumoniae (hvKP) causing community-acquired, invasive, metastatic, life-threatening infections of lungs, pleura, prostate, bones, joints, kidneys, spleen, muscles, soft-tissues, skin, eyes, central nervous system (CNS) including extrahepatic abscesses, and primary bacteremia even in healthy individuals has posed stern challenges before the existing treatment modalities. There is therefore an urgent need to look for specific and effective therapeutic alternatives against the said bacterial infection or recurrence. A new type of MoS 2 -modified curcumin nanostructure has been developed and evaluated as a potential alternative for the treatment of multidrug-resistant isolates. The curcumin quantum particles have been fabricated with MoS 2 via a seed-mediated hydrothermal method, and the resulting MoS 2 -modified curcumin nanostructures (MQCs) have been subsequently tested for their antibacterial and antibiofilm properties against hypervirulent multidrug-resistant Klebsiella pneumoniae isolates. In the present study, we found MQCs inhibiting the bacterial growth at a minimal concentration of 0.0156 μg/mL, while complete inhibition of bacterial growth was evinced at concentration 0.125 μg/mL. Besides, we also investigated their biocompatibility both in vitro and in vivo. MQCs were found to be nontoxic to the SiHa cells at a dose as high as 1024 μg/ mL on the basis of the tested adhesion, spreading of the cells, and also on the various serological, biochemical, and histological investigations of the vital organs and blood of the Charles Foster Rat. These results suggest that MQCs have potent antimicrobial activities against hvKP and other drug resistant isolates and therefore may be used as broad spectrum antibacterial and antibiofilm agents.

The solid to smecticG (SmG) phase transition in a Schiff base liquid crystalline compound, terepthal-bis-heptylaniline (TB7A), is monitored in situ by temperature-dependent Raman microspectroscopy, using the band of a C-H in-plane bending mode as a marker. Contrary to the earlier report of a sudden wavenumber shift, the in situ measurement shows very clearly that a new Raman band at ∼1160 cm −1 appears at the Crystal II → SmG transition. The dynamics of this phase transition is discussed in terms of a triple well potential below 210 K and a double well potential above 210 K. The phase transition essentially takes place as a result of intra-molecular rotation about the long molecular axis. The optimization energy at various fixed dihedral angles, (-C-C-C N-) are calculated using density functional theory (DFT) at the B3LYP/6-31G * level of theory. The relative energy at each dihedral angle is calculated relative to optimization energy obtained without any constraints and plotted as a function of dihedral angle ( ) between the adjacent phenyl ring planes, which also shows a double well potential at room temperature.

Precise polarized Raman measurements of 2-chloropyridine (2Clpy) in the region 560-1060 cm −1 and 3-chloropyridine (3Clpy) in the region 680-1080 cm −1 at different concentrations in mole fraction of methanol were made to calculate the isotropic part of the Raman spectra, which has contributions only from vibrational dephasing. A detailed analysis of the Raman spectra was carried out to see the variation of peak position and linewidth. The dephasing is mode specific. The trigonal bending mode of 3Clpy has two components when it is mixed with methanol. The relative intensities of these two bands are used to calculate the equilibrium constants. The ring-breathing mode of 3Clpy, on the other hand, remains single in the mixture. The appearance of a new band corresponding to the trigonal bending mode, as well as the nonappearance of that of the ring-breathing mode, is also shown by the density functional theory (DFT) study of gas phase and methanol-solvated complexes. The vibrational dephasing time for the hydrogen-bonded ring-breathing mode is calculated from the linear Raman linewidth and peak position data. For other modes, it was not possible to calculate the dephasing time because of the nonavailability of a suitable theoretical model. Contrary to 3Clpy, in 2Clpy the ring-breathing mode becomes a doublet but the trigonal bending mode remains single. It is seen that the hydrogen-bonding capacity of chloropyridines is highly influenced by the position of the Cl atom. Single and double components of these modes are also explained by DFT calculations. We obtained excellent match of the experimental and theoretical spectra with the B3LYP/6-31+G (d,p) method.