Key Points• Despite a low frequency of mutations, BCOR might be considered as a key gene in risk stratification. • Deep sequencing technologiesshow that BCOR mutations commonly arise after other concomitant mutations in MDS.Patients with low-risk myelodysplastic syndromes (MDS) that rapidly progress to acute myeloid leukemia (AML) remain a challenge in disease management. Using whole-exome sequencing of an MDS patient, we identified a somatic mutation in the BCOR gene also mutated in AML. Sequencing of BCOR and related BCORL1 genes in a cohort of 354 MDS patients identified 4.2% and 0.8% of mutations respectively. BCOR mutations were associated with RUNX1 (P 5 .002) and DNMT3A mutations (P 5 .015). BCOR is also mutated in chronic myelomonocytic leukemia patients (7.4%) and BCORL1 in AML patients with myelodysplasia-related changes (9.1%). Using deep sequencing, we show that BCOR mutations arise after mutations affecting genes involved in splicing machinery or epigenetic regulation. In univariate analysis, BCOR mutations were associated with poor prognosis in MDS (overall survival [OS]: P 5 .013; cumulative incidence of AML transformation: P 5 .005). Multivariate analysis including age, International Prognostic Scoring System, transfusion dependency, and mutational status confirmed a significant inferior OS to patients with a BCOR mutation (hazard ratio, 3.3; 95% confidence interval, 1.4-8.1; P 5 .008). These data suggest that BCOR mutations define the clinical course rather than disease initiation. Despite infrequent mutations, BCOR analyses should be considered in risk stratification. (Blood. 2013;122(18):3169-3177)

The generalised oscillator strength formalism is used to calculate a complete and self-consistent set of collision cross sections for incident electron energies ranging from thresholds up to 10 MeV. Results are reported for about 40 states with an emphasis given on the ionisation processes. The study of the loss function points out the importance of the inner-shell ionisation, which consumes nearly as much energy as the excitation and the ionisation of the outer shell. Moreover, the authors show that the mean energy of the secondaries ejected from a given shell is about twice the ionisation potential of this shell. As a result, many energetic secondary electrons coming from inner-shell ionisation are present in the plasmas produced by relativistic electron beams.

Detailed experimental and theoretical studies of a phototriggered XeCl excimer laser have been performed through the development and the experimental validation of a zero-dimensional model, which self-consistently coupled the solution of the Boltzmann equation, the kinetic equations of heavy particles, the electrical circuit and the photon equations. A detailed description of the XeCl molecule and of the associated kinetics has been taken into account, together with the effect of the gas temperature growth on the stimulated emission cross section. The model predictions have been compared with the experimental results obtained from a complete set of time-resolved electrical and optical diagnostics including emission and laser absorption spectroscopy on various xenon and neon states. A specific output energy of 7.6 J l-1 and an efficiency of 3.5% are reported, which indicates the effectiveness of the phototriggered discharges to produce high-performance excimer lasers. Simple rules allowing the calculation of the required voltage for best efficiency or maximum output laser energy are given.

The discharge equilibrium and the F-atom production kinetics in a phototriggered HF laser using gas mixtures containing Ne and with hydrogen or ethane have been investigated. Coupled experimental and theoretical studies have been carried out, through a 0D discharge modelling and measurements of the current, of the voltage and of the extracted laser energy, together with emission spectroscopy on F 3p excited states. A quantitative comparison of the total F-atom density produced in mixtures of with or is performed and the results are compared with the discharge pumped HF laser performance achieved with these molecules. An overall validation of the model has been obtained, both for the energy transfer to the active media and for the kinetics of F and its excited states. It is shown that the transmitted energy and electrical charge, as well as the discharge electric field, weakly depend on the type and on the concentration of the RH molecule, or , in the gas mixtures. Moreover, the F-atom production depends very slightly on the nature of RH. Therefore the fact that the laser performance achieved with hydrogen is lower than the performance achieved with ethane is not due to differences in the energy transfer and in the F-atom production kinetics in mixtures of with or .

Characteristics of phototriggered discharges in pure argon and neon have been experimentally and theoretically investigated at pressures between 0.5 and 5 bars and reduced electric fields E/N in the range 5 to 50 Td. Emphasis is laid on the breakdown delay time, defined as the time lag between the application of a very short preionization pulse and the occurrence of the discharge. The model, developed in the frame of the local field approximation, gives breakdown delay time values in excellent agreement with the experimental results. However, in pure neon, the experiments have revealed a large influence of very small amounts of easily ionizable impurities. The calculations point out that the discharge behavior is mainly determined by the electron multiplication rate due to direct ionization of ground state atoms. Other ionizing processes, such as two-step ionization or Penning effects, or the electrical parameters of the circuit (inductance, capacitance, and intensity of the preionization) have only a secondary effect on the breakdown delay time.