Modelling the response of whispering-gallery-mode optical resonators for biosensing applications

In recent years, sharp photonic resonances of dielectric microspheres, so-called whispering gallery modes (WGMs), have emerged as powerful transducer for sensing applications. The long photon lifetime of the modes together with the small surface area of the microresonator is promising for their use as sensitive probes of changes in the surrounding medium. In this work we present a theoretical analysis of the response of WGMs for biosensing applications, studied numerically in microcylinders and semi-analytically in microspheres. In both cases, we consider a layout where WGMs are excited via frustrated total internal reflection from a planar substrate, as reported in recent experiments. The effect of single and multiple particles is calculated, simulating biological analytes of different sizes and polarizabilities attached to the microresonator surface. For microcylinders, cylinder-shaped particle are considered, to retain a 2D numerical problem. Besides WGM frequency shifts, we find that also broadenings and splittings (from lifted rotational symmetry) appear due to particles attachment and/or the vicinity to the planar substrate. In particular, for a single analyte, both particle size and refractive index can be determined from the WGM broadening and shift, opening the perspective to a new biosensing modality. In microspheres, a perturbation method is used to model shifts and splittings of WGMs in the presence of point-like particles and global shape perturbations. Due to the large azimuthal degeneracy of the modes without perturbation, the resulting mode spectrum is rich and offers a fingerprint of the perturbation

Accelerating Medicines Partnership® Schizophrenia (AMP® SCZ):Rationale and Study Design of the Largest Global Prospective Cohort Study of Clinical High Risk for Psychosis

This article describes the rationale, aims, and methodology of the Accelerating Medicines Partnership® Schizophrenia (AMP® SCZ). This is the largest international collaboration to date that will develop algorithms to predict trajectories and outcomes of individuals at clinical high risk (CHR) for psychosis and to advance the development and use of novel pharmacological interventions for CHR individuals. We present a description of the participating research networks and the data processing analysis and coordination center, their processes for data harmonization across 43 sites from 13 participating countries (recruitment across North America, Australia, Europe, Asia, and South America), data flow and quality assessment processes, data analyses, and the transfer of data to the National Institute of Mental Health (NIMH) Data Archive (NDA) for use by the research community. In an expected sample of approximately 2000 CHR individuals and 640 matched healthy controls, AMP SCZ will collect clinical, environmental, and cognitive data along with multimodal biomarkers, including neuroimaging, electrophysiology, fluid biospecimens, speech and facial expression samples, novel measures derived from digital health technologies including smartphone-based daily surveys, and passive sensing as well as actigraphy. The study will investigate a range of clinical outcomes over a 2-year period, including transition to psychosis, remission or persistence of CHR status, attenuated positive symptoms, persistent negative symptoms, mood and anxiety symptoms, and psychosocial functioning. The global reach of AMP SCZ and its harmonized innovative methods promise to catalyze the development of new treatments to address critical unmet clinical and public health needs in CHR individuals.</p