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Paediatric haematology began to establish itself as a speciality in the UK just over 60 years ago. In that time, clinical trials involving all the specialist centres in the country, and based on scientific advances, have dramatically improved the outlook for children with a range of malignant and non-malignant disorders, but particularly acute leukaemia. As in many specialties, multidisciplinary teams have played a major role in delivering these advances. With these structures in place at a national level, perhaps, of all specialities, paediatric haematology is poised to benefit from the new developments in precision medicine, gene editing and immunotherapy.

We performed ab initio calculations for the PbTiO3/SrTiO3 (001) heterostructures. For both PbO and TiO2-terminations of the PbTiO3 (001) thin film, augmented on the SrTiO3 (001) substrate, the magnitudes of atomic relaxations Δz increases as a function of the number of augmented monolayers. For both terminations of the augmented PbTiO3 (001) nanothin film, all upper, third and fifth monolayers are displaced inwards (Δz is negative), whereas all second, fourth and sixth monolayers are displaced outwards (Δz is positive). The B3PW calculated PbTiO3/SrTiO3 (001) heterostructure band gaps, independently from the number of augmented layers, are always smaller than the PbTiO3 and SrTiO3 bulk band gaps. For both PbO and TiO2-terminated PbTiO3/SrTiO3(001) heterostructures, their band gaps are reduced due to the increased number of PbTiO3 (001) monolayers. The band gaps of PbO-terminated augmented PbTiO3 (001) films are always larger than those for TiO2-terminated PbTiO3 (001) thin films. The only exception is the case of 7-layer PbO-terminated and 8-layer TiO2-terminated augmented PbTiO3 (001) thin films, where their band gaps both are equal to 2.99 eV. For each monolayer of the SrTiO3 (001) substrate, charge magnitudes always are more than several times larger, than for each monolayer in the augmented PbTiO3 (001) thin film. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present and discuss the results of calculations of the CaF2 bulk and surface electronic structure. These are based on the ab initio Hartree – Fock (HF) method with electron correlation corrections and on Density Functional Theory (DFT) calculations with different exchange-correlation functionals, including hybrid exchange techniques. Both approaches use the localised Gaussian-type basis set. According to our calculations the ab initio HF method considerably overestimates (20.77 eV) the optical band gap, whereas the density functional calculations based on the Kohn – Sham equation with a number of exchange-correlation functionals, including local density approximation (LDA) (8.72 eV), generalized gradient approximations (GGA) by Perdew and Wang (PW) (8.51 eV), and Perdew, Burke, and Ernzerhof (PBE) (8.45 eV) underestimate it. Our results show that the best agreement with experiment (12.1 eV) can be obtained using a hybrid HF – DFT exchange functional, in which Hartree – Fock exchange is mixed with DFT exchange functionals, using Beckes three parameter method, combined with the non-local correlation functionals by Perdew and Wang (B3PW) (10.96 eV). We also present calculations of CaF2(111), (110), and (100) surfaces. Our calculated surface energies using the hybrid B3PW method confirm that the CaF2(111) surface is the most stable one, in agreement with the experiment.

A review of recent theoretical and experimental studies of bi-polaronic excitons, charge transfer vibronic excitons (CTVEs), in ionic-covalent solids is presented. CTVEs are electronic polaron - hole polaron pairs or triads, strongly interacting with the lattice and displaying a good defined, strong electric dipole moment under conditions of cross-relaxation reorientation. New type states (CTVE-phase), new type phenomena (CTVE-induced ferroelectric phase transition), and possible applications (tuneable CTVE-laser effect and CTVE-induced photorefraction) are discussed. KTaO 3 and KNbO 3 systems are considered.

We present results for basic intrinsic defects: F-type electron centers, free and bound electron and hole polarons in ABO3 perovskites. Both one-site (atomic) and two-site (molecular) hole polarons are expected to coexist, characterized by close absorption energies. Shell Model (SM) and intermediate neglect of differential overlap (INDO) calculations of the F center diffusion indicate that the relevant activation energy is quite low, ca. 0.8 eV. Further INDO calculations support the existence of self-trapped electron polarons in PbTiO3, BaTiO3, KNbO3, and KTaO3 crystals. The relevant lattice relaxation energies are typically 0.2 eV, whereas the optical absorption energies are around 0.8 eV. We also used the INDO method for modelling the atomic and electronic structure of KNbxTa1–xO3 (KTN) perovskite solid solutions. The Nb impurities in KTaO3 reveal off-center displacements starting with the smallest calculated concentrations. The calculated magnitude of the displacement is close to the EXAFS observation. Using the calculated energy gain for several concentrations of Nb in KTN, we construct the Ginzburg-Landau-type functional for the excess energy. The coefficients of this functional are concentration-dependent. This dependence allows us to define the type of concentration-induced phase transition in KTaO3 alloyed by Nb. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The results of electronic structure calculations for different terminations of SrTiO 3 (100) and (110) perovskite thin films are discussed. These calculations are based on the ab initio Hartree-Fock (HF) method and Density Functional Theory (DFT). Results are compared with previous ab initio plane-wave LDA and classical Shell Model (SM) calculations. Calculated considerable increase of the Ti-O chemical bond covalency nearby the surface is confirmed by experimental data. Our quantum chemical calculations performed by means of the intermediate neglect of differential overlap (INDO) method confirm the existence of self-trapped electrons in KNbO 3 , KTaO 3 and BaTiO 3 crystals. The relevant lattice relaxation energies are 0.21 eV, 0.27 eV and 0.24 eV, and the optical absorption energies 0.78 eV, 0.75 eV and 0.69 eV, respectively. We suggest a theoretical interpretation of the so-called green luminescence (2.2-2.3 eV) in ABO 3 perovskite crystals as a result of the recombination of electrons and holes forming the Charge-Transfer-Vibronic-Exciton (CTVE). The calculated luminescence energies for SrTiO 3 , BaTiO 3 , KNbO 3 and KTaO 3 perovskite crystals are in a good agreement with the experimentally observed energies.

Using previous results for the equilibrium geometries of stoichiometric (Al 2 O 3 ) n clusters as models for non ideal alumina surfaces, we obtain, from ab-initio total energy LCAO calculations, the corresponding relaxed structures of the complexes H 2 O-(Al 2 O 3 ) n with n ≤ 7. Depending on the initial position of the water molecule relative to the cluster site, the complex evolves to different equilibrium structures, with and without dissociation of H 2 O, whose energetic, bond lengths, and charge transfer trends are studied as the morphology and size of the initial cluster change. Dissociation of H 2 O with the radical OH - bound on top of an Al atom and the proton H + bound to the second nearest neighbour O, is the dominant process for the reaction (Al 2 O 3 ) n + H 2 O with n = 4, in agreement with the one observed for the adsorption of H 2 O on the extended real surface.

Current lithium-ion batteries are the state-of-the-art power sources for consumer electronics operating mainly in the 4 V regime. One frequently discussed direction to improve the performance of such batteries is the development of a family of 5 V cathode materials. We report here a Full Potential Linearized Augmented Plane Wave (FP-LAPW) calculation for Li2Co1Mn3O8 in the Fdm spinel structure. Our calculated battery voltage for this material is around 5 V. This result is stable against interchange of positions of Mn and Co atoms as well as the choice of the position of the Li vacancy. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

BACKGROUND: Tranexamic acid (TXA) reduces blood transfusion in surgery but the extent of the reduction in blood loss and how it relates to the dose of TXA is unclear. METHODS: A systematic review of randomized trials was performed. Data were extracted on blood loss from trials comparing intravenous TXA with no TXA or placebo in surgical patients. A Bayesian linear regression was used to describe the relationship between the reduction in blood loss with TXA and the extent of bleeding as measured by the mean blood loss in the control group. A meta-analysis of the log-transformed data was conducted to quantify the effect of TXA on blood loss, stratified by type of surgery, timing of TXA administration and trial quality. Meta-regression was used to explore the effect of TXA dosage. RESULTS: Data from 104 trials were examined. Although the absolute reduction in blood loss with TXA increased as surgical bleeding increased, the percentage reduction was similar. TXA reduced blood loss by 34 per cent (pooled ratio 0·66, 95 per cent confidence interval 0·65 to 0·67; P < 0·001). The percentage reduction in blood loss with TXA differed by type of surgery, timing of TXA administration and trial quality, but the differences were small. The effect of TXA on blood loss did not vary over the range of doses assessed (5·5-300 mg/kg). CONCLUSION: TXA reduces blood loss in surgical patients by about one-third. A total dose of 1 g appears to be sufficient for most adults. There is no evidence to support the use of high doses.

Results of computer simulations of the kinetics of correlated annealing of pairs of close α–I and F–I centers in KCI and KBr crystals, enhanced by I-center diffusion and Coulomb or elastic attractions, respectively, are presented. Special attention is paid to the conditions under which multi-stage annealing stages arise as it has been observed experimentally more than once. Our general conclusions are: (i) a weak elastic interaction affects the recombination kinetics and the survival probability even for relatively well-separated F–I pairs, the more so is true for the case of Coulomb attraction between charged α–I pairs; (ii) the multi-step (kink) structure arises only for close (typically, up to fourth-nearest neighbour) defects. To explain the strongly separated stages observed experimentally for α–I (17 to 21 K, 30 to 39 K in KCI and 18 to 22 K and 27 to 30 K in KBr) a very particular initial distribution of defects is required consisting of two groups of close and well-separated defects. It gives strong support to the results of recent computer simulations that an interstitial ion created due to electron trapping by an H center can be transformed into a crowdion which could be displaced athermally by a long distance from a vacancy (five to seven interionic distances).

The authors withdraw their article in phys. stat. sol. (b) 242, 2041 (2005) [1] because parts of it have been published in Physical Review B [2].