The aim of this study was to explore the impact of polymorphism of PD-1 gene and its interaction with tea drinking on susceptibility to tuberculosis (TB). A total of 503 patients with TB and 494 controls were enrolled in this case–control study. Three single-nucleotide polymorphisms of PD-1 (rs7568402, rs2227982 and rs36084323) were genotyped and unconditional logistic regression analysis was used to identify the association between PD-1 polymorphism and TB, while marginal structural linear odds models were used to estimate the interactions. Genotypes GA (OR 1.434), AA (OR 1.891) and GA + AA (OR 1.493) at rs7568402 were more prevalent in the TB patients than in the controls (P < 0.05). The relative excess risk of interaction (RERI) between rs7568402 of PD-1 genes and tea drinking was −0.3856 (95% confidence interval −0.7920 to −0.0209, P < 0.05), which showed a negative interaction. However, the RERIs between tea drinking and both rs2227982 and rs36084323 of PD-1 genes were not statistically significant. Our data demonstrate that rs7568402 of PD-1 genes was associated with susceptibility to TB, and there was a significant negative interaction between rs7568402 and tea drinking. Therefore, preventive measures through promoting the consumption of tea should be emphasised in the high-risk populations.

Ceramics are strong but brittle. According to the classical theories, ceramics are brittle mainly because dislocations are suppressed by cracks. Here, the authors report the combined elastic and plastic deformation measurements of nanoceramics, in which dislocation-mediated stiff and ductile behaviors were detected at room temperature. In the synchrotron-based deformation experiments, a marked slope change is observed in the stress–strain relationship of MgAl2O4 nanoceramics at high pressures, indicating that a deformation mechanism shift occurs in the compression and that the nanoceramics sample is elastically stiffer than its bulk counterpart. The bulk-sized MgAl2O4 shows no texturing at pressures up to 37 GPa, which is compatible with the brittle behaviors of ceramics. Surprisingly, substantial texturing is seen in nanoceramic MgAl2O4 at pressures above 4 GPa. The observed stiffening and texturing indicate that dislocation-mediated mechanisms, usually suppressed in bulk-sized ceramics at low temperature, become operative in nanoceramics. This makes nanoceramics stiff and ductile.

The integration of synchrotron and high-pressure techniques has significantly advanced research in materials science, giving rise to many important discoveries in physics, chemistry, environmental science, and many other fields of physical and engineering sciences. The relevant frontier work in multiple disciplines is reviewed. The selected studies include high-pressure superconductivity, lattice dynamics of materials, plastic deformation of nanomaterials, polyamorphic transitions and devitrification in metallic glass, rheology of minerals, and high-pressure chemistry probing.

Recent ex situ observations of crystallization in both natural and synthetic systems indicate that the classical models of nucleation and growth are inaccurate. However, in situ observations that can provide direct evidence for alternative models have been lacking due to the limited temporal and spatial resolution of experimental techniques that can observe dynamic processes in a bulk solution. Here we report results from liquid cell transmission electron microscopy studies of nucleation and growth of Au, CaCO3, and iron oxide nanoparticles. We show how these in situ data can be used to obtain direct evidence for the mechanisms underlying nanoparticle crystallization as well as dynamic information that provide constraints on important energetic parameters not available through ex situ methods.

Chromium-doped (0.5-10 % Cr:Ti molar ratio) nanocrystalline titania (5–6 nm) prepared via sol-gel method was examined by synchrotron-based wide angle x-ray scattering (WAXS) for crystal structure determination. Atomic pair-distribution functions (PDF) for both raw and heat-treated samples were obtained by Fourier transforms of the WAXS data. The PDF data were fitted using structural models of nanocrystalline titania that considered phase compositions, lattice parameters, atomic positions and thermal factors. The unit cell of Cr-doped nanocrystalline titania expanded 1-2 % with respect to bulk titania as a consequence of the substitution of Ti by Cr and the generation of oxygen vacancies. We observed a lattice contraction after heat-treatment that may be caused by the redistribution of Cr atoms to nanoparticle surfaces during phase transformation and particle coarsening.

The kinetics of phase transformation of nanocrystalline anatase samples was studied using x-ray diffraction at temperatures ranging from 600 to 1150 °C. Kinetic data were analyzed with an interface nucleation model and a newly proposed kinetic model for combined interface and surface nucleation. Results revealed that the activation energy of nucleation is size dependent. In anatase samples with denser particle packing, rutile nucleates primarily at interfaces between contacting anatase particles. In anatase samples with less dense particle packing, rutile nucleates at both interfaces and free surfaces of anatase particles. The predominant nucleation mode may change from interface nucleation at low temperatures to surface nucleation at intermediate temperatures and to bulk nucleation at very high temperatures. Alumina particles dispersed among the anatase particles can effectively reduce the probability of interface nucleation at all temperatures.

Initial thermodynamic analysis predicts surface tension of fine solid particles decreases with decrease in particle size. Free energy of fine solid particles increases with decrease in particle size. In the nanocrystalline TiO2 system, the surface tensions and the surface energies of both anatase and rutile were estimated by modeling available thermochemical data and kinetic data. The particle size versus temperature phase diagram of the nanocrystalline TiO2 system was calculated, which reveals 1–8 nm anatase is more stable than rutile of the same size at certain temperatures.