A self-referenced in-situ arrival time monitor for X-ray free-electron lasers

We present a novel, highly versatile, and self-referenced arrival time monitor for measuring the femtosecond time delay between a hard X-ray pulse from a free-electron laser and an optical laser pulse, measured directly on the same sample used for pump-probe experiments. Two chirped and picosecond long optical supercontinuum pulses traverse the sample with a mutually fixed time delay of 970 fs, while a femtosecond X-ray pulse arrives at an instant in between both pulses. Behind the sample the supercontinuum pulses are temporally overlapped to yield near-perfect destructive interference in the absence of the X-ray pulse. Stimulation of the sample with an X-ray pulse delivers non-zero contributions at certain optical wavelengths, which serve as a measure of the relative arrival time of the X-ray pulse with an accuracy of better than 25 fs. We find an excellent agreement of our monitor with the existing timing diagnostics at the SACLA XFEL with a Pearson correlation value of 0.98. We demonstrate a high sensitivity to measure X-ray pulses with pulse energies as low as 30 $\mu$J. Using a free-flowing liquid jet as interaction sample ensures the full replacement of the sample volume for each X-ray/optical event, thus enabling its utility even at MHz repetition rate XFEL sources

The OTUD6B-LIN28B-MYC axis determines the proliferative state in multiple myeloma

Deubiquitylases (DUBs) are therapeutically amenable components of the ubiquitin machinery that stabilize substrate proteins. Their inhibition can destabilize oncoproteins that may otherwise be undruggable. Here, we screened for DUB vulnerabilities in multiple myeloma, an incurable malignancy with dependency on the ubiquitin proteasome system and identified OTUD6B as an oncogene that drives the G1/S-transition. LIN28B, a suppressor of microRNA biogenesis, is specified as a bona fide cell cycle-specific substrate of OTUD6B. Stabilization of LIN28B drives MYC expression at G1/S, which in turn allows for rapid S-phase entry. Silencing OTUD6B or LIN28B inhibits multiple myeloma outgrowth in vivo and high OTUD6B expression evolves in patients that progress to symptomatic multiple myeloma and results in an adverse outcome of the disease. Thus, we link proteolytic ubiquitylation with post-transcriptional regulation and nominate OTUD6B as a potential mediator of the MGUS-multiple myeloma transition, a central regulator of MYC, and an actionable vulnerability in multiple myeloma and other tumors with an activated OTUD6B-LIN28B axis.</p

Ultrafast quantum control of ionization dynamics

The unprecedented combination of transient absorption and ion mass spectroscopy with attosecond resolution is used to study and control the complex multidimensional excitation and decay cascade of an ultrafast Auger process in krypton

Ultrafast quantum control of ionization dynamics in krypton

Photoionization of atoms and molecules is a complex process and requires sensitive probes to explore the ultrafast dynamics. Here the authors combine transient absorption and photo-ion spectroscopy methods to explore and control the attosecond pulse initiated excitation, ionization and Auger decay in Kr atoms

Environmental Mapping and Analysis Program – A German Hyperspectral Mission

EnMAP (Environmental Mapping and Analysis Program) is a German hyperspectral earth observation satellite. Its spectral measurements will be used to obtain a diagnostic characterization of the earth's surface and to derive quantitative surface parameters on the status of terrestrial and aquatic ecosystems and the changes they undergo. EnMAP data will supply a basis for quantifying and modeling crucial ecosystem processes, thereby making a major contribution toward understanding the complexities of the Earth system. The satellite system is being developed entirely in Germany under the aegis of the Space Administration of the German Aerospace Center (DLR), with the launch scheduled for 2018. EnMAP carries a push broom type hyperspectral instrument with 30 km swath width at a ground sampling distance of 30 m, covering the full range of strong solar irradiation from 420 nm to 2450 nm with two spectrometers, one each for the VNIR and SWIR range. It will be operated for five years on a sun-synchronous orbit with a local time descending node (LTDN) at 11:00. At near nadir orientation (±5°) the repeat rate of EnMAP is 27 days. Using the across track platform pointing capability of ±30° enables frequent access to any global site within four days, allowing short term evolutions of ecosystems to be studied with high precision. Data takes can be acquired with an accumulated length of 5000 km along track per day, with individual segments ranging from 30 km to 1000 km. Image data are down linked via the Neustrelitz ground station using an X-band link at 320 MBit/s