RESUMO
FinEstBeAMS (Finnish-Estonian Beamline for Atmospheric and Materials Sciences) is a multidisciplinary beamline constructed at the 1.5â GeV storage ring of the MAX IV synchrotron facility in Lund, Sweden. The beamline covers an extremely wide photon energy range, 4.5-1300â eV, by utilizing a single elliptically polarizing undulator as a radiation source and a single grazing-incidence plane grating monochromator to disperse the radiation. At photon energies below 70â eV the beamline operation relies on the use of optical and thin-film filters to remove higher-order components from the monochromated radiation. This paper discusses the performance of the beamline, examining such characteristics as the quality of the gratings, photon energy calibration, photon energy resolution, available photon flux, polarization quality and focal spot size.
RESUMO
The d-spacing of the multilayer lamellar grating was theoretically optimized to improve the energy resolution and maintain a high efficiency. Based on the study of the growth behavior of Mo/Si multilayer on the lamellar grating under different sputtering pressures, Ar gas pressure of 1 mTorr was selected, which can fabricate the multilayer with lower roughness and a good replication of the groove shape. An absolute diffraction efficiency of 25.6% and a Cff factor of 1.79 were achieved for the -1st order of the Mo/Si lamellar multilayer grating at an energy of 1700 eV.
RESUMO
The optimized design of multilayer-coated blazed gratings (MLBG) for high-flux tender X-ray monochromators was systematically studied by numerical simulations. The resulting correlation between the multilayer d-spacing and grating blaze angle significantly deviated from the one predicted by conventional equations. Three high line density gratings with different blaze angles were fabricated and coated by the same Cr/C multilayer. The MLBG with an optimal blaze angle of 1.0° showed a record efficiency reaching 60% at 3.1 keV and 4.1 keV. The measured efficiencies of all three gratings were consistent with calculated results proving the validity of the numerical simulation and indicating a more rigorous way to design the optimal MLBG structure.
RESUMO
The protein kinase family represents an enormous opportunity for drug development. However, the current limitation in structural diversity of kinase inhibitors has complicated efforts to identify effective treatments of diseases that involve protein kinase signaling pathways. We have identified a new structural class of protein serine/threonine kinase inhibitors comprising an aminoimidazo[1,2-a]pyridine nucleus. In this report, we describe the first successful use of this class of aza-heterocycles to generate potent inhibitors of cyclin-dependent kinases that compete with ATP for binding to a catalytic subunit of the protein. Co-crystal structures of CDK2 in complex with lead compounds reveal a unique mode of binding. Using this knowledge, a structure-based design approach directed this chemical scaffold toward generating potent and selective CDK2 inhibitors, which selectively inhibited the CDK2-dependent phosphorylation of Rb and induced caspase-3-dependent apoptosis in HCT 116 tumor cells. The discovery of this new class of ATP-site-directed protein kinase inhibitors, aminoimidazo[1,2-a]pyridines, provides the basis for a new medicinal chemistry tool to be used in the search for effective treatments of cancer and other diseases that involve protein kinase signaling pathways.