The cough reflex in anaesthetized rabbits was elicited by irritation of the larynx with ammonia, inhalation of ammonia into the lungs, and mechanical stimulation of the tracheobronchial tree with a catheter. After block of lung stretch receptors with sulphur dioxide and virtual abolition of the Breuer-Hering inflation reflex, the cough response to all three stimuli was far less frequent and, when it occurred, was weaker especially with respect to the expiratory efforts. It is concluded that the Breuer-Hering reflex enhances the cough reflex, although modification of the sensitivity of tracheobronchial cough and irritant receptors by sulphur dioxide may also influence the cough.
Supramolecular coordination complexes (SCCs) have been proposed for applications necessitating photon emitting properties; however, two critical characteristics, facile tunability and high emission quantum yields, have yet to be demonstrated on SCC platforms. Herein, a series of functionalized D2h [D2A2] rhomboids (D = 2,6-bis(4-ethynylpyridine)aniline-based ligands; A = 2,9-bis[trans-Pt(PEt3)2NO3]phenanthrene) is described with emission wavelengths spanning the visible region (λmax = 476-581 nm). Tuning was achieved by simple functional group modifications para to the aniline amine on the donor building block. Steady-state absorption and emission profiles were obtained for each system and are discussed. When the Hammett σ(para) constants for the functional groups para to the aniline amine were plotted versus the wavenumber (cm(-1)) for the λmax of the emission profile, a linear relationship was observed. By utilizing this relationship, the emission wavelength of a given rhomboid can be predetermined on the basis of the Hammett constant of the functionality employed on the donor precursor. This range of visible light emission for a suite of simple rhomboids along with the predictive nature of the wavelength of emission is unprecedented for these types of systems.
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