Bioactive glass ionomer cements (GICs) have been in widespread use for ∼40 years in dentistry and medicine. However, these composites fall short of the toughness needed for permanent implants. Significant impediment to improvement has been the requisite use of conventional destructive mechanical testing, which is necessarily retrospective. Here we show quantitatively, through the novel use of calorimetry, terahertz (THz) spectroscopy and neutron scattering, how GIC’s developing fracture toughness during setting is related to interfacial THz dynamics, changing atomic cohesion and fluctuating interfacial configurations. Contrary to convention, we find setting is non-monotonic, characterized by abrupt features not previously detected, including a glass–polymer coupling point, an early setting point, where decreasing toughness unexpectedly recovers, followed by stress-induced weakening of interfaces. Subsequently, toughness declines asymptotically to long-term fracture test values. We expect the insight afforded by these in situ non-destructive techniques will assist in raising understanding of the setting mechanisms and associated dynamics of cementitious materials.

Computer simulations of the Mg ²⁺ dehydration mechanism show that solution additives can stabilise undercoordinated Mg ²⁺ hydration configurations, opening up coordination sites on the central Mg ²⁺ ion, promoting Mg-carbonates nucleation and growth.

Penicillin, travels through bodily fluids, targeting and acylatively inactivating enzymes responsible for cell-wall synthesis in gram-positive bacteria. Somehow, it avoids metabolic degradation remaining inactive en route. To resolve this ability to switch from a non-active, to a highly reactive form, we investigated the dynamic structure–activity relationship of penicillin by inelastic neutron spectroscopy, reaction kinetics, NMR and multi-scale theoretical modelling (QM/MM and post-HF ab initio). Results show that by a self-activating physiological pH-dependent two-step proton-mediated process, penicillin changes geometry to activate its irreversibly reactive acylation, facilitated by systemic intramolecular energy management and cooperative vibrations. This dynamic mechanism is confirmed by the first ever reported characterisation of an antibiotic by neutrons, achieved on the TOSCA instrument (ISIS facility, RAL, UK).

The structure, energetics and radical scavenging potency of theaflavin (TF), a natural polyphenolic antioxidant found in oxidised tea, have been characterised by a series of density functional theory (DFT) determinations. Exploratory conformational searches yielded 153 distinct neutral structures. Results showed TF's structural preferences to be regulated by its unique fused double ring benzotropolone moiety, and its degree of planarity, with structural diversity, principally arising from variations of its nine –OH groups. The distinct 3D conformational ‘poses’ are shown to be stabilised by a complex network of intra-system interactions, damping overall structural floppiness. This rigidification, together with stability, is shown to be coupled with radical scavenging potency in the TF system. Radical scavenging via hydrogen atom abstraction (HAB) in H₂O solution was determined to be spontaneous with very low reaction barriers (ΔG_rel ∼ 4 kJ mol⁻¹).

Ab initio and DFT conformational analysis was performed on the flavone derivatives chrysin (5,7-dihydroxyflavone; 2-phenyl-5,7-dihydroxy-4H-1-benzopyran-4-one) and 7,8-dihydroxyflavone (2-phenyl-7,8-dihydroxy-4H-1-benzopyran-4-one). The structural features required for optimal stabilization in each molecule were identified. It was discovered that sparsely placed hydroxyl groups, particularly with hydrogen bond-like interactions, resulted in lowering the potential energy minimum for the molecules. It was also noted that one of the factors capable of destroying co-planarity was steric interference between closely placed functional groups across the phenyl and the benzo-γ-pyrane ring. Studies performed on the radical forms of the flavonoids, however, showed that the unpaired electron is confined only to the benzo-γ-pyrane ring, and not delocalized across the phenyl ring.Key words: flavonoid, flavone, chrysin, ab initio conformational analysis, anti-oxidant, free radical, 5,7-dihydroxy flavone, 7,8-dihydroxyflavone.