Michael Bache’s research while affiliated with Technical University of Denmark and other places

The water/ethanol system possesses complexities at the molecular level, which render its description a difficult task. For the elucidation of the system’s hydrogen bonding features that are the key factors in its complex behavior, we conduct a Density Functional Theory analysis on relevant water/ethanol clusters inside implicit solvent cavities for the determination of the ethanol donor hydrogen bond strength. We record Attenuated Total Reflectance spectra of water/ethanol-OD solutions and utilize our density and refractive index measurements for post-processing. The application of the Badger–Bauer rule reveals a minimum in the strength of the ethanol donor hydrogen bond for a composition of xwater = 0.74. We attempt to analyze further this result by estimating the effect of the implicit solvent on the ethanol donor hydrogen bond strength, finding it to be incremental. A brief analysis of different cluster conformations is carried out to determine the cooperativity conditions that can potentially explain the observed minimum in the ethanol donor hydrogen bond strength. These observations are related to notions of microheterogeneity in water/alcohol mixtures and provide context toward a more elaborate picture of association in heteroclusters.

Water is a fascinating substance with lots of properties not encountered in other compounds. It has been suggested that making use of water's “anomalous” properties can lead to exciting applications in various disciplines e.g. engineering, medicine and physiology. The origin of these anomalous properties is far from clear, with the strong hydrogen bonds of water being only part of the answer. Moreover, water's structure and dynamics are not entirely understood either and new theories have appeared and debated during the 21st century. This review, aiming at a broader/general audience, attempts to review briefly We review some research trends related to water's structure, properties and applications. New experimental results for the debated phenomena of water bridge and exclusion zone are also presented and discussed. Various explanatory mechanisms for the exclusion zone are reviewed and a new proposal is put forward. A –hopefully- unbiased discussion is presented for both “mainstream” and unconventional theories and trends and future directions are also outlined.

Featured Application Weak resonant magnetic fields may provide a non-chemical application towards combating antimicrobial resistance such as biofilm formation by pathogenic bacteria. Abstract The global rise of antimicrobial resistance (AMR) constitutes a future health threat and dictates a need to explore alternative and non-chemical approaches. The aim of this study was to explore the use of weak resonant electromagnetic fields as a method to disrupt biofilm formation of a pathogenic bacterium in cystic fibrosis patients. We developed a bioresonance laboratory setup able to distinguish between changes in planktonic growth and changes in biofilm formation and showed that certain resonant frequencies were able to affect biofilm formation without affecting planktonic growth. In addition, we show that the ambient day-to-day magnetic field affects biofilm formation in a non-consistent manner. Overall, we conclude that our assay is suitable for studying the potential of resonant magnetic fields as a treatment and prevention strategy to prevent biofilm infections, and that certain resonant frequencies may be used as future medical applications to combat antimicrobial resistance.

Vibrational spectra for chiral isomers of the neuropeptide Dermorphin are measured and analyzed in different solvents using FT-IR, Raman spectroscopy and computational means. This is in order to understand the effect that different solvents have on the corresponding spectra of peptides with chiral (L,D) amino-acid isomers. The D-Alanine form of particularly Dermorphin is many times more potent than the L-Alanine form, which we attribute predominantly to the influence of the solvents. The solvents investigated are H2O/D2O, DMSO and chloroform. They were chosen due to their varied polarity. The study is an experimental complement to the theoretical studies of the structure of Dermorphin and its docking to the µ (mu)-Receptor. The conclusions about the restrictions of the conformational space and the dynamical degrees of freedom are being assessed by vibrational spectroscopy. The main results derived from the experimental spectra of Dermorphin L/D-Alanine in various solvents, is the pronounced difference between the chiral forms, especially seen in the water solvent due to the strong polarity shift resulting from mutating the second position of the peptide from an L- to a D-Alanine.