Chiral expression at the nanoscale origin and recognition of chirality

Chirality, familiar to all chemists, is usually applied to molecules or assemblies of molecules and plays an important role in both animate and inanimate systems. It is commonly the case that chirality of a system arises from a chiral building block yet chiral systems can also emerge from achiral units. The objective of this research was to investigate the origin and recognition of chirality at the nanoscale level. To do this, self assembled monolayers made of chirally and achirally tailed molecules were used because such structures are known to form uniform surfaces, which can act as either a source of nucleation or the probing surfaces in chiral recognition. The strategy adopted in the first part of this study was to use chirally modified self assembled monolayers as a source of nucleation for crystallization of achiral compounds that can form either left or right tended forms in chiral crystallization. Such compounds, widely reviewed by Matsura, form chiral crystals even though their building blocks lack a chiral centre. This study presents experiments of induction of chirality in sodium chlorate, hippuric acid and 2,6-ditertbutyl-4-methylphenol crystals. Chiral crystallization of chosen compounds was conducted on D and L cysteine surfaces assembled on gold. The chirality of crystals grown on these surfaces was determined using polarised light microscopy, circular dichroism spectroscopy and NSOM. The small enantiomeric excess achieved in experiments was explained by the limits of chirality determination methods. It was found that crystals formed in enantiomeric excess were of opposite chirality to the SAM they were grown on. This confirms previous results presented by Mastai on crystallization of histidine on cysteine surfaces. The second part of this study presents studies of chiral recognition use of AFM technique-Force Distance Spectroscopy. Chirally and achirally modified SAMs were formed via the Cu-AAC reaction commonly called 'click Chemistry'. This project investigated how the surface preparation influences chiral recognition and if the presence of the second chiral centre affects probing ability. For surface preparation, three types of linkers were used. To functionalize them two complementary compounds equipped with AlaAlaDL and AlaAlaLL dipeptide tail were used. Additional studies were carried out with hippuric acid and glutamic acid-modified SAMs. These studies showed that the way the surface is prepared plays an important role in chiral recognition. In the final recognition experiments it was found that use of molecules possessing either peptide groups or amino acid groups generates additional forces between interacting surfaces, which can be equilibrated by conducting measurements in pH close to their isoelectric point. An influence of the second chiral centre was found for the loosely packed surfaces where the molecules can freely coil

Ethical issues in biomedical research using electronic health records : a systematic review

Digitization of a health record changes its accessibility. An electronic health record (EHR) can be accessed by multiple authorized users. Health information from EHRs contributes to learning healthcare systems’ development. The objective of this systematic review is to answer a question: What are ethical issues concerning research using EHRs in the literature? We searched Medline Ovid, Embase and Scopus for publications concerning ethical issues of research use of EHRs. We employed the constant comparative method to retrieve common ethical themes. We descriptively summarized empirical studies. The study reveals the breadth, depth, and complexity of ethical problems associated with research use of EHRs. The central ethical question that emerges from the review is how to manage access to EHRs. Managing accessibility consists of interconnected and overlapping issues: streamlining research access to EHRs, minimizing risk, engaging and educating patients, as well as ensuring trustworthy governance of EHR data. Most of the ethical problems concerning EHR-based research arise from rapid cultural change. The framing of concepts of privacy, as well as individual and public dimensions of beneficence, are changing. We are currently living in the middle of this transition period. Human emotions and mental habits, as well as laws, are lagging behind technological developments. In the medical tradition, individual patient’s health has always been in the center. Transformation of healthcare care, its digitalization, seems to have some impacts on our perspective of health care ethics, research ethics and public health ethics. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11019-021-10031-6