Jak budowa molekularna i warunki termodynamiczne (p-T) wpływają na dynamikę molekularną monoalkoholi oraz dioli?

Alcohols are studied from the beginning of the twentieth century in order to find answers to many fundamental questions related to the specific properties of materials containing hydrogen bonds. The unique properties of these compounds is not only the ability to easily supercooling to a glassy state, but above all the fact that in some of them (with single OH group in the structure), the dynamics of the hydrogen bonds can be monitored directly with a broadband dielectric spectroscopy (BDS) in a very wide range of times, from 10-9s to 103s. Therefore, studies on molecular dynamics of monoalcohols are essential for understanding the properties of associative materials. In the case of polyols (diols have in the structure two OH groups) we do not directly observe the relaxation process responsible for the occurrence of supramolecular structures, however, their research provides a lot of additional information about the effect of hydrogen bonds and structures created by them on the properties of associative liquids. Despite intense research, there is still no answer to some of the fundamental questions, including how does the molecular structure affects the molecular dynamics of alcohols under the influence of various thermodynamic conditions, whether the increase in pressure will affect the relaxation dynamics of the alcohol mixture with the non-dissolving solvent?The key task in the course of the conducted research, which form the basis of the presented doctoral dissertation, was to answer the questions that concerned issues related to the molecular dynamics of mono- and polyalcohols: 1) How does the architecture of molecules affect the molecular dynamics of simple alcohols? What is the role of thermodynamic conditions? 2) In the mixture of 2-ethyl-1-hexanol with 2-ethylhexylbromide (2E1H / 2E1Br) with a sufficiently high alcohol concentration there is the possibility of simultaneous testing of Debye's and structural relaxation properties also under high pressure conditions. This in turn gives the opportunity to find an answer to the question, what is the effect of different thermodynamic conditions on the dynamics of 2-ethyl-1-hexanol 2E1H dynamics, and in particular on structural relaxation? 3) How do thermodynamic conditions and differences in the architecture of molecules, including the addition of a second hydroxyl group, affect the properties of diols

Density Scaling Based Detection of thermodynamic Regions of complex intermolecular interactions characterizing Supramolecular Structures

In this paper, applying the density scaling idea to an associated liquid 4-methyl-2-pentanol used as an example, we identify different pressure-volume-temperature ranges within which molecular dynamics is dominated by either complex H-bonded networks most probably leading to supramolecular structures or non-specific intermolecular interactions like van der Waals forces. In this way, we show that the density scaling law for molecular dynamics near the glass transition provides a sensitive tool to detect thermodynamic regions characterized by intermolecular interactions of different type and complexity for a given material in the wide pressure-volume-temperature domain even if its typical form with constant scaling exponent is not obeyed. Moreover, we quantify the observed decoupling between dielectric and mechanical relaxations of the material in the density scaling regime. The suggested methods of analyses and their interpretations open new prospects for formulating models based on proper effective intermolecular potentials describing physicochemical phenomena near the glass transition

Inflection point in the Debye relaxation time of 2-butyl-1-octanol

International audienceWe report a striking anomaly in the pressure dependent Debye-relaxation time of the branched monohydroxy alcohol 2-butyl-1-octanol. Evidence of a crossover from slower to faster than exponential pressure dependency was obtained at different temperatures via high pressure broadband dielectric spectroscopy. At the same time, viscosity measurements reveal similar behavior in the viscosity respectively the structural relaxation time, indicating a similar origin of the phenomena

Effect of Drugs Used in Pharmacotherapy of Type 2 Diabetes on Bone Density and Risk of Bone Fractures

This review summarizes the complex relationship between medications used to treat type 2 diabetes and bone health. T2DM patients face an increased fracture risk despite higher bone mineral density; thus, we analyzed the impact of key drug classes, including Metformin, Sulphonylureas, SGLT-2 inhibitors, DPP-4 inhibitors, GLP-1 agonists, and Thiazolidinediones. Metformin, despite promising preclinical results, lacks a clear consensus on its role in reducing fracture risk. Sulphonylureas present conflicting data, with potential neutral effects on bone. SGLT-2 inhibitors seem to have a transient impact on serum calcium and phosphorus, but evidence on their fracture association is inconclusive. DPP-4 inhibitors emerge as promising contributors to bone health, and GLP-1 agonists exhibit positive effects on bone metabolism, reducing fracture risk. Thiazolidinediones, however, demonstrate adverse impacts on bone, inducing loss through mesenchymal stem cell effects. Insulin presents a complex relationship with bone health. While it has an anabolic effect on bone mineral density, its role in fracture risk remains inconsistent. In conclusion, a comprehensive understanding of diabetes medications’ impact on bone health is crucial. Further research is needed to formulate clear guidelines for managing bone health in diabetic patients, considering individual profiles, glycemic control, and potential medication-related effects on bone