7 research outputs found
Direct Observation of a Feshbach-resonance by Coincidence-detection of Ions and Electrons in Penning Ionization Collisions
Observation of molecular dynamics with quantum state resolution is one of the
major challenges in chemical physics. Complete characterization of collision
dynamics leads to the microscopic understanding and unraveling of different
quantum phenomena such as scattering resonances. We present a new experimental
approach for observing molecular dynamics involving neutral particles and ions
that is capable in providing state-to-state mapping of the dynamics. We use
Penning ionization reaction between argon and metastable helium to generate
argon ion and ground state helium atom pairs at separation of several
angstroms. The energy of ejected electron carries the information about the
initial electronic state of an ion. The coincidence detection of ionic products
provides a state resolved description of the post-ionization ion-neutral
dynamics. We demonstrate that correlation between the electron and ion energy
spectra enables us to directly observe the spin-orbit excited Feshbach
resonance state of HeAr. We measure the lifetime of the quasi-bound
HeAr A state and discuss possible applications of our method
Immunological resilience and biodiversity for prevention of allergic diseases and asthma
Increase of allergic conditions has occurred at the same pace with the Great Acceleration, which stands for the rapid growth rate of human activities upon earth from 1950s. Changes of environment and lifestyle along with escalating urbanization are acknowledged as the main underlying causes. Secondary (tertiary) prevention for better disease control has advanced considerably with innovations for oral immunotherapy and effective treatment of inflammation with corticosteroids, calcineurin inhibitors, and biological medications. Patients are less disabled than before. However, primary prevention has remained a dilemma. Factors predicting allergy and asthma risk have proven complex: Risk factors increase the risk, while protective factors counteract them. Interaction of human body with environmental biodiversity with micro-organisms and biogenic compounds as well as the central role of epigenetic adaptation in immune homeostasis have given new insight. Allergic diseases are good indicators of the twisted relation to environment. In various non-communicable diseases, the protective mode of the immune system indicates low-grade inflammation without apparent cause. Giving microbes, pro- and prebiotics, has shown some promise in prevention and treatment. The real-world public health programme in Finland (2008-2018) emphasized nature relatedness and protective factors for immunological resilience, instead of avoidance. The nationwide action mitigated the allergy burden, but in the lack of controls, primary preventive effect remains to be proven. The first results of controlled biodiversity interventions are promising. In the fast urbanizing world, new approaches are called for allergy prevention, which also has a major cost saving potential.Peer reviewe