New Strong-Field QED Effects at ELI: Nonperturbative Vacuum Pair Production

Since the work of Sauter, and Heisenberg, Euler and K\"ockel, it has been understood that vacuum polarization effects in quantum electrodynamics (QED) predict remarkable new phenomena such as light-light scattering and pair production from vacuum. However, these fundamental effects are difficult to probe experimentally because they are very weak, and they are difficult to analyze theoretically because they are highly nonlinear and/or nonperturbative. The Extreme Light Infrastructure (ELI) project offers the possibility of a new window into this largely unexplored world. I review these ideas, along with some new results, explaining why quantum field theorists are so interested in this rapidly developing field of laser science. I concentrate on the theoretical tools that have been developed to analyze nonperturbative vacuum pair production.Comment: 20 pages, 9 figures; Key Lecture at the ELI Workshop and School on "Fundamental Physics with Ultra-High Fields", 29 Sept - 2 Oct. 2008, Frauenworth Monastery, Germany; v2: refs updated, English translations of reviews of Nikishov and Ritu

Effects of Cr Microalloying on Structural Evolution, Crystallization Behavior and Micromechanical Properties of ZrCoAlCr Bulk Metallic Glass

This paper deals with the role of minor addition of Cr on the atomic rearrangement and crystallization evolution in a Zr-based bulk metallic glass. For this purpose, Cr elements with 1–4% atomic percentage were added into the alloying composition. The X-ray diffraction results indicated that the trace element led to the increase in disordered structures in the glassy alloy and the decline in population of short and medium scale orders. This event was due to the intensification of structural heterogeneity which was manifested in the change of enthalpy relaxation. The differential scanning calorimetry analysis also showed that all ZrCoAlCr BMG samples included two distinct crystallization peaks during the heating process. However, the increase in Cr content led to the intensification of low temperature peak. This result was consistent with viscosity analysis, in which the viscosity decrement was intensified at the range of low temperature crystallization peak with the rise in Cr content. Moreover, it was found that although the plasticity improved in samples with Cr-content, the strength showed a slight decrease

P53 long noncoding RNA regulatory network in cancer development

The protein p53 as a transcription factor with strong tumor-suppressive activities is known to trigger apoptosis via multiple pathways and is directly involved in the recognition of DNA damage and DNA repair processes. P53 alteration is now recognized as a common event in the pathogenesis of many types of human malignancies. Deregulation of tumor suppressor p53 pathways plays an important role in the activation of cell proliferation or inactivation of apoptotic cell death during carcinogenesis and tumor progression. Mounting evidence indicates that the p53 status of tumors and also the regulatory functions of p53 may be relevant to the long noncoding RNAs (lncRNA)-dependent gene regulation programs. Besides coding genes, lncRNAs that do not encode for proteins are induced or suppressed by p53 transcriptional response and thus control cancer progression. LncRNAs also have emerged as key regulators that impinge on the p53 signaling network orchestrating global gene-expression profile. Studies have suggested that aberrant expression of lncRNAs as a molecular-genomic signature may play important roles in cancer biology. Accordingly, it is important to elucidate the mechanisms by which the crosstalk between lncRNAs and p53 occurs in the development of numerous cancers. Here, we review how several classes of lncRNAs and p53 pathways are linked together in controlling the cell cycle and apoptosis in various cancer cells in both human and mouse model systems