Publications by authors named "P Lenzen"

The structure and spin of photoexcited Fe(phen) in water are examined by x-ray scattering and x-ray emission spectroscopy with 100 ps time resolution. Excitation of the low-spin (LS) ground state (GS) to the charge transfer state MLCT leads to the formation of a high-spin (HS) state that returns to the GS in 725 ps. Density functional theory (DFT) predicts a Fe-N bond elongation in HS by 0.

View Article and Find Full Text PDF

Viscosity of protein solutions is a critical product quality attribute for protein therapeutics such as monoclonal antibodies. Here we introduce a portable single-use analytical chip-based viscometer for determining the viscosity of protein solutions using low sample volumes of 10 μL. Through the combined use of a microfluidic viscometer, a smartphone camera for image capture, and an automated data processing algorithm for the calculation of the viscosity of fluids, we enable measurement of viscosity of multiple samples in parallel.

View Article and Find Full Text PDF

This work investigates and describes the structural dynamics taking place following charge-transfer-to-solvent photo-abstraction of electrons from I and Br ions in aqueous solution following single- and 2-photon excitation at 202 nm and 400 nm, respectively. A Time-Resolved X-ray Solution Scattering (TR-XSS) approach with direct sensitivity to the structure of the surrounding solvent as the water molecules adopt a new equilibrium configuration following the electron-abstraction process is utilized to investigate the structural dynamics of solvent shell expansion and restructuring in real-time. The structural sensitivity of the scattering data enables a quantitative evaluation of competing models for the interaction between the nascent neutral species and surrounding water molecules.

View Article and Find Full Text PDF

Background: Hypertensive disorders of pregnancy (HDP) are associated with increased long-term risk for cardiometabolic risk factors (chronic hypertension [HTN], obesity, diabetes) and heart failure. Exercise capacity is a known predictor of heart failure in patients with normal resting cardiac filling pressures. In this prospective observational cohort study, we sought to identify predictors of reduced postpartum exercise capacity in participants with normotensive vs preeclamptic pregnancies.

View Article and Find Full Text PDF