MARK DRISCOLL: Absolute Erotic, Absolute Grotesque The Living, Dead, and Undead in Japan’s Imperialism, 1895–1945

http://dx.doi.org/10.13185/ST2013.0111

Nanoscale diffractive probing of strain dynamics in ultrafast transmission electron microscopy

The control of optically driven high-frequency strain waves in nanostructured systems is an essential ingredient for the further development of nanophononics. However, broadly applicable experimental means to quantitatively map such structural distortion on their intrinsic ultrafast time and nanometer length scales are still lacking. Here, we introduce ultrafast convergent beam electron diffraction (U-CBED) with a nanoscale probe beam for the quantitative retrieval of the time-dependent local distortion tensor. We demonstrate its capabilities by investigating the ultrafast acoustic deformations close to the edge of a single-crystalline graphite membrane. Tracking the structural distortion with a 28-nm/700-fs spatio-temporal resolution, we observe an acoustic membrane breathing mode with spatially modulated amplitude, governed by the optical near field structure at the membrane edge. Furthermore, an in-plane polarized acoustic shock wave is launched at the membrane edge, which triggers secondary acoustic shear waves with a pronounced spatio-temporal dependency. The experimental findings are compared to numerical acoustic wave simulations in the continuous medium limit, highlighting the importance of microscopic dissipation mechanisms and ballistic transport channels

Penetrance of pathogenic mutations in haploinsufficient genes for intellectual disability and related disorders

De novo loss of function (LOF) mutations in the ASXL3 gene cause Bainbridge-Ropers syndrome, a severe form of intellectual disability (ID) and developmental delay, but there is evidence that they also occur in healthy individuals. This has prompted us to look for non-pathogenic LOF variants in other ID genes. Heterozygous LOF mutations in ASXL1, a paralog of ASXL3, are known to cause Bohring-Opitz syndrome (BOS), and benign LOF mutations in this gene have not been published to date. Therefore, we were surprised to find 56 ASXL1 LOF variants in the ExAC database (http://exac.broadinstitute.org), comprising exomes from 60,706 individuals who had been selected to exclude severe genetic childhood disorders. 4 of these variants have been described as disease-causing in patients with BOS, which rules out the possibility that pathogenic and clinically neutral LOF variants in this gene are functionally distinct. Apparently benign LOF variants were also detected in several other genes for ID and related disorders, including CDH15, KATNAL2, DEPDC5, ARID1B and AUTS2, both in the ExAC database and in the 6,500 exomes of the Exome Variant Server (http://evs.gs.washington.edu/EVS/). These observations argue for low penetrance of LOF mutations in ASXL1 and other genes for ID and related disorders, which could have far-reaching implications for genetic counseling and research

Generation and bistability of a waveguide nanoplasma observed by enhanced extreme-ultraviolet fluorescence

We present a study of the highly nonlinear optical excitation of noble gases in tapered hollow waveguides using few-femtosecond laser pulses. The local plasmonic field enhancement induces the generation of a nanometric plasma, resulting in incoherent extreme-ultraviolet fluorescence from optical transitions of neutral and ionized xenon, argon, and neon. Despite sufficient intensity in the waveguide, high-order harmonic generation is not observed. The fluorescent emission exhibits a strong bistability manifest as an intensity hysteresis, giving strong indications for multistep collisional excitations

Nanoscale mapping of ultrafast magnetization dynamics with femtosecond Lorentz microscopy

Novel time-resolved imaging techniques for the investigation of ultrafast nanoscale magnetization dynamics are indispensable for further developments in light-controlled magnetism. Here, we introduce femtosecond Lorentz microscopy, achieving a spatial resolution below 100 nm and a temporal resolution of 700 fs, which gives access to the transiently excited state of the spin system on femtosecond timescales and its subsequent relaxation dynamics. We demonstrate the capabilities of this technique by spatio-temporally mapping the light-induced demagnetization of a single magnetic vortex structure and quantitatively extracting the evolution of the magnetization field after optical excitation. Tunable electron imaging conditions allow for an optimization of spatial resolution or field sensitivity, enabling future investigations of ultrafast internal dynamics of magnetic topological defects on 10-nanometer length scales

Nonlinear Light Generation in Localized Fields Using Gases and Tailored Solids

n Chap. 18, we demonstrated polarization-sensitive imaging at extreme-ultraviolet (EUV) wavelengths using a gas-phase high-harmonic generation (HHG) source. In a related project, we have investigated new types of gas-phase and solid-state EUV light sources employing field localization in plasmonic nanostructures and structured targets. Whereas our first results indicate that strong field confinement leads to exceedingly inefficient high-harmonic generation in gas-phase targets, for solid-state media efficient high-harmonic generation is possible in localized fields. The latter has great ramifications for new types of high-harmonic generation experiments and technological developments. Therefore, our research efforts aim in two directions: firstly, the development of new types of solid-state sources for high-harmonic generation and, secondly, the application of locally generated solid-state high-harmonic signals for spectroscopy and imaging

Rare diseases: human genome research is coming home

After a long and largely disappointing detour, Genome Research has reidentified Rare Diseases as a major opportunity for improving health care and a clue to understanding gene and genome function. In this Special Issue of CSH Molecular Case Studies on Rare Diseases, several invited Perspectives, numerous Case Reports, and this Editorial itself address recent breakthroughs as well as unsolved problems in this wide field. These range from exciting prospects for gap-free diagnostic whole-genome sequencing to persisting problems related to identifying and distinguishing pathogenic and benign variants; and from the good news that soon, the United Kingdom will no longer be the only country to have introduced whole-genome sequencing into health care to the sobering conclusion that in many countries the clinical infrastructure for bringing Genome Medicine to the patient is still lacking. With less than 5000 genes firmly implicated in disease, the identification of at least twice as many disease genes is a major challenge, and the elucidation of their function is an even larger task. But given the renewed interest in rare diseases, their importance for health care, and the vast and growing spectrum of concepts and methods for studying them, the future of Human Genome Research is bright