Lead-borate glasses manifest unique structure with lead oxide composition owing to their dual role of modifier and former. The medium-range signature from the first sharp diffraction peak (FSDP) in lead-borates exhibits substantial correlations due to the presence of superstructural units. Pressure plays an important role in altering bonding characteristics and hence structure in materials. To understand pressure-induced changes in the medium-range order (MRO) in lead-borate glasses, we have carried out high pressure X-ray diffraction studies in the FSDP region of these glasses up to 25 GPa. Two clear peaks, $q_0$ and $q_1$ are observed in all the modified glasses, below and above the position of the FSDP in pure B$_2$O$_3$ glass. This shows that lead oxide alters the FSDP and causes changes in the network structure at the MRO. $q_1$ exhibits an increase under compression, resulting in a reduction in correlation lengths for all glass compositions.The initial steep decrease is accompanied by a lower rate of reduction at higher pressures. This shows that correlations arising from structural voids in the boron matrix exhibit similar decrease for various lead oxide compositions.

High pressure behaviour of core/shell amorphous carbon (a-C) nanostructures was studied using synchrotron X-ray diffraction (XRD) and Raman spectroscopy up to ${\sim}$25 GPa. These nanostructures having spherical a-C shells with ${\gamma}$-Fe$_2$O$_3$ nanoparticles at the core were synthesized by catalyst-assisted lamp black method. The typical size of core (${\gamma}$-Fe$_2$O$_3$)/shell (a-C) is ${\sim}$5 nm/20 nm. Comparative XRD of the core (${\gamma}$-Fe$_2$O$_3$) in opened- and closed-shell (a-C) shows that the carbon shells do not fully transmit the applied high pressure inwards, under hydrostatic conditions. Raman spectroscopy shows that the graphitic G-mode blue shifts reversibly with applied pressure with a coefficient ${\sim}$3.5 cm$^{-1}$ GPa$^{-1}$, which is ${\sim}$25 to 40% less than that for graphite and carbon nanotubes. It is suggested that a rigid and crosslinked structure of the carbon shell might be lossy for the observed pressure drop.