17 research outputs found
Quartz-based flat-crystal resonant inelastic x-ray scattering spectrometer with sub-10 meV energy resolution
Continued improvement of the energy resolution of resonant inelastic x-ray
scattering (RIXS) spectrometers is crucial for fulfilling the potential of this
technique in the study of electron dynamics in materials of fundamental and
technological importance. In particular, RIXS is the only alternative tool to
inelastic neutron scattering capable of providing fully momentum resolved
information on dynamic spin structures of magnetic materials, but is limited to
systems whose magnetic excitation energy scales are comparable to the energy
resolution. The state-of-the-art spherical diced crystal analyzer optics
provides energy resolution as good as 25 meV but has already reached its
theoretical limit. Here, we demonstrate a novel sub-10meV RIXS spectrometer
based on flat-crystal optics at the Ir-L absorption edge (11.215 keV)
that achieves an analyzer energy resolution of 3.9meV, very close to the
theoretical value of 3.7meV. In addition, the new spectrometer allows
efficient polarization analysis without loss of energy resolution. The
performance of the instrument is demonstrated using longitudinal acoustical and
optical phonons in diamond, and magnon in SrIrO. The novel
sub-10meV RIXS spectrometer thus provides a window into magnetic
materials with small energy scales
Advances, challenges and future directions for stem cell therapy in amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative condition where loss of motor neurons within the brain and spinal cord leads to muscle atrophy, weakness, paralysis and ultimately death within 3–5 years from onset of symptoms. The specific molecular mechanisms underlying the disease pathology are not fully understood and neuroprotective treatment options are minimally effective.
In recent years, stem cell transplantation as a new therapy for ALS patients has been extensively investigated, becoming an intense and debated field of study. In several preclinical studies using the SOD1G93A mouse model of ALS, stem cells were demonstrated to be neuroprotective, effectively delayed disease onset and extended survival. Despite substantial improvements in stem cell technology and promising results in preclinical studies, several questions still remain unanswered, such as the identification of the most suitable and beneficial cell source, cell dose, route of delivery and therapeutic mechanisms. This review will cover publications in this field and comprehensively discuss advances, challenges and future direction regarding the therapeutic potential of stem cells in ALS, with a focus on mesenchymal stem cells. In summary, given their high proliferation activity, immunomodulation, multi-differentiation potential, and the capacity to secrete neuroprotective factors, adult mesenchymal stem cells represent a promising candidate for clinical translation. However, technical hurdles such as optimal dose, differentiation state, route of administration, and the underlying potential therapeutic mechanisms still need to be assessed