Exciton Transfer Between Extended Electronic States in Conjugated Inter-Polyelectrolyte Complexes.

Artificial light harvesting, a process that involves converting sunlight into chemical potential energy, is considered to be a promising part of the overall solution to address urgent global energy challenges. Conjugated polyelectrolyte complexes (CPECs) are particularly attractive for this purpose due to their extended electronic states, tunable assembly thermodynamics, and sensitivity to their local environment. Importantly, ionically assembled complexes of conjugated polyelectrolytes can act as efficient donor-acceptor pairs for electronic energy transfer (EET). However, to be of use in material applications, we must understand how modifying the chemical structure of the CPE backbone alters the EET rate beyond spectral overlap considerations. In this report we investigate the dependence of the EET efficiency and rate on the electronic structure and excitonic wave function of the CPE backbone. To do so, we synthesized a series of alternating copolymers where the electronic states are systematically altered by introducing comonomers with electron withdrawing and electron-rich character while keeping the linear ionic charge density nearly fixed. We find evidence that the excitonic coupling may be significantly affected by the exciton delocalization radius, in accordance with analytical models based on the line-dipole approximation and quantum chemistry calculations. Our results imply that care should be taken when selecting CPE components for optimal CPEC EET. These results have implications for using CPECs as key components in water-based light-harvesting materials, either as standalone assemblies or as adsorbates on nanoparticles and thin films.

Granulocytic sarcoma - a rare presentation of a breast lump.

This report describes a woman who presented with a breast lump, which was initially misdiagnosed as lymphoma, but later turned out to be granulocytic sarcoma of the breast.

The introduction of family presence evidence-based practice into a baccalaureate nursing curriculum.

The topic of family presence (FP) during cardiopulmonary resuscitation or invasive procedures has recently received attention and debate among healthcare professionals due to pioneering research in this field. Studies completed have included family perspectives on family presence, patients' feelings on family presence, and healthcare providers' views on family presence. Two key areas found to correlate with family presence acceptance among healthcare providers are education and experience. Senior nursing students in one baccalaureate program were introduced to this topic during a 3-hour class on death and dying. Comparisons between pretest and posttest scores revealed an increase in the acceptance of family presence as a priority in nursing care of the critically ill.