For the past year, Louisa has been working with X-ray fluorescence to scan manuscripts from the Johnson Museum, mining deposits from deep below earth, and other samples to train users on the benefits of using the high energy x-rays at CHESS to peer inside, or through their samples.
The intense push in the subsequent month and a half – involving virtually all of the CHESS technical staff – completed the biggest and most significant upgrade to G-line since 2004.
Turns out that shipping heavy equipment back and forth to schools (even all the way to California) throughout the academic year results in a lot of broken items. We often don’t have enough time between shipments to completely fix all of the equipment, so we use spares and place the broken items in a pile until there is a long enough period of time to fix them. Yes, you guessed it, we wait for the summer break.
Firstly, hydrogen peroxide reacts with Fe(III) heme of CcP to form an Fe(IV) iron oxo species [Fe(IV)=O], and oxidizes its nearby tryptophan 191 (W191) to a radical cation (W•⁺). Secondly, the presence of W•⁺ facilitates the transfer of electrons from Cc proteins when Cc Fe(II) is oxidized, causing the reduction of CcP W•⁺ to W191. The CcP Fe(IV)=O then re-oxidizes W191 back to its radical cation state, resulting in the eventual formation of Fe(III) and water.
Extensive research studying the bulk and catalytic properties of STO as well as characterizing its surface structure in ultra-high vacuum and in atmosphere is in the literature. However, little is known about the structure of the STO/electrolyte interface under photocatalytic conditions, even less is known about the effect of surface structure on its catalytic properties.
The seemingly mundane little droplets of liquid we put into the X-ray beam are rare bits and pieces of the machinery of life, painstakingly separated and purified from Nature’s unimaginably complex brew. Suspended delicately in solution, biological molecules are fussy, sensitive, and sometimes barely present at all. Researchers play a game of roulette when they try to concentrate samples enough to get useful X-ray scattering signals: not enough concentration and the signal is too weak, too much concentration and the molecules may crash out of solution becoming irretrievably lost.
They are joined by their theory collaborator Igor I. Potemkin (Lomonosov Moscow State University) and former Papadakis postdoc Jianqi Zhang who is now at the National Center of Nanoscience and Technology in Beijing, as well as current postdoc Anatoly Berezkin (TUM).
The CHESS-U project has many facets. The CESR accelerator gets upgraded with multi-bend achromat magnet technology, converts to running only a single particle beam, and enhances the energy from 5.3 to 6.0 GeV and 200 milliAmperes. With a single type of charged particle in the machine, half of the x-ray beamlines will be turned around and rebuilt to handle the heat load, and deliver the much higher photon flux, of individually tunable undulator sources. Overall, the laboratory is being optimized to deliver ultra-high-flux, high energy x-ray beams for future experiments.
Carbon-fibre-reinforced-carbon (aka “carbon-carbon” or “C/C”) is a leading, tough, low-density material that has been extensively used for these applications. Despite its many advantages, C/C does suffer from being susceptible to oxidization, and must therefore be coated with some protective layer prior to use. The residual and thermally-induced strains between C/C and its protective coatings must be understood in order to engineer safer, lighter vehicles.
Trifluoromethyl (CF3) substituents profoundly influence properties of organic molecules and transition metal complexes. Medicinal chemists have recognized the value of the CF3 group for advantageous drug properties including increased physiological longevity, facile blood−brain barrier penetration, and enhanced protein−substrate binding affinities. Consequently, developing reactions that install CF3 on organic frameworks is a major research goal.