Maximizing atmospheric-disturbed fiber coupling efficiency with speckle-based phase retrieval and a single-pixel camera.

An approach to adaptive optics utilizing a single-pixel camera (SPC) is proposed to maximize fiber coupling efficiency at the receiver side of an optical satellite-to-ground link perturbed by atmospheric turbulence. Using a single-pixel wavefront sensor enables operation at longer optical wavelengths, such as near and far infrared, which have advantageous propagation characteristics for free space optical communication. In this approach, a focal plane intensity image of the atmospheric-disturbed wavefront is taken via an SPC using a compressed sensing technique. An iterative speckle-based phase retrieval algorithm is then applied to infer the phase distortion corrected by a deformable mirror in a feedback loop. This computational approach to inferring the phase of the wavefront overcomes the limitations of traditional Shack-Hartman-based approaches, which are difficult to implement at high speed and at the long infrared wavelengths proposed for future optical satellite communication downlinks. It has been shown that fiber coupling efficiency is increased from less than 5% to 40%-50% in medium-to-strong turbulence scenarios with the phase retrieval algorithm proposed in this work.

Obesity dysregulates the pulmonary antiviral immune response.

Obesity is a well-recognized risk factor for severe influenza infections but the mechanisms underlying susceptibility are poorly understood. Here, we identify that obese individuals have deficient pulmonary antiviral immune responses in bronchoalveolar lavage cells but not in bronchial epithelial cells or peripheral blood dendritic cells. We show that the obese human airway metabolome is perturbed with associated increases in the airway concentrations of the adipokine leptin which correlated negatively with the magnitude of ex vivo antiviral responses. Exogenous pulmonary leptin administration in mice directly impaired antiviral type I interferon responses in vivo and ex vivo in cultured airway macrophages. Obese individuals hospitalised with influenza showed dysregulated upper airway immune responses. These studies provide insight into mechanisms driving propensity to severe influenza infections in obesity and raise the potential for development of leptin manipulation or interferon administration as novel strategies for conferring protection from severe infections in obese higher risk individuals.