Clusters and Nanocrystals

Clusters and nanocrystals constitute intermediates between molecules and condensed matter. Due to their finite size, clusters have a wide spectrum of applications ranging from building blocks for novel materials to model systems for fundamental investigations about light-matter interactions. Short-wavelength radiation from synchrotron radiation sources and free-electron lasers allows the detailed investigation of their geometric, electronic, and magnetic structure as well as dynamical processes. Conversely, clusters can serve as idealized sample systems for the development of new experimental techniques and pioneering experiments with novel x-ray sources. The chapter starts with a brief introduction to cluster physics, followed by a comprehensive overview of research performed at synchrotron light sources on van der Waals, metal, and semiconductor clusters. With the advent of short-wavelength free-electron lasers, a new research field in the x-ray peak intensity regime has opened. Experiments on single clusters, such as x-ray imaging and tracing ultrafast dynamics, now become possible

Proposed Guidelines for the Diagnosis and Management of Methylmalonic and Propionic Acidemia

Methylmalonic and propionic acidemia (MMA/PA) are inborn errors of metabolism characterized by accumulation of propionic acid and/or methylmalonic acid due to deficiency of methylmalonyl-CoA mutase (MUT) or propionyl-CoA carboxylase (PCC). MMA has an estimated incidence of ~ 1: 50,000 and PA of ~ 1:100’000 -150,000. Patients present either shortly after birth with acute deterioration, metabolic acidosis and hyperammonemia or later at any age with a more heterogeneous clinical picture, leading to early death or to severe neurological handicap in many survivors. Mental outcome tends to be worse in PA and late complications include chronic kidney disease almost exclusively in MMA and cardiomyopathy mainly in PA. Except for vitamin B12 responsive forms of MMA the outcome remains poor despite the existence of apparently effective therapy with a low protein diet and carnitine. This may be related to under recognition and delayed diagnosis due to nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity., These guidelines aim to provide a trans-European consensus to guide practitioners, set standards of care and to help to raise awareness. To achieve these goals, the guidelines were developed using the SIGN methodology by having professionals on MMA/PA across twelve European countries and the U.S. gather all the existing evidence, score it according to the SIGN evidence level system and make a series of conclusive statements supported by an associated level of evidence. Although the degree of evidence rarely exceeds level C (evidence from non-analytical studies like case reports and series), the guideline should provide a firm and critical basis to guide practice on both acute and chronic presentations, and to address diagnosis, management, monitoring, outcomes, and psychosocial and ethical issues. Furthermore, these guidelines highlight gaps in knowledge that must be filled by future research. We consider that these guidelines will help to harmonize practice, set common standards and spread good practices, with a positive impact on the outcomes of MMA/PA patients.PubMedWoSScopu