Volume 8, Issue 2

Porphyrins or more broadly defined porphyrinoids are the structures where the extended π -cloud can be significantly modified by several factors. The broad range of introduced structural motifs has shown a possibility of modification of conjugation by a controlled synthetic approach, leading to expected optical or magnetic behaviour, and also by post-synthetic modifications (i.e. redox or protonation/deprotonation), Both approaches lead to noticeab changes in observed properties but also open a potential for further utilization. Thus, this already constituted big family of macrocyclic structures with specific highly extended π -delocalization shows a significant contribution in several fields from fundamental studies, leading to understanding behaviour of skeletons like that with a substantial influence on biological studies and material science. The presented material focuses on the most significant examples of modifications of porphyrinoids skeleton leading to drastic changes in optical response and magnetic properties. Through the presentation, the focus will be placed on the changes leading to the most red-shifted transition as the parameter indicating extending the π -delocalization. Significantly different magnetic character will be also discussed based on the switching between aromatic/antiaromatic character assigned to macrocyclic structures that will be included.

Magnetic particle imaging (MPI) is a young imaging modality for biomedical applications. It uses magnetic nanoparticles as a tracer material to produce three-dimensional images of the spatial tracer distribution in the field-of-view. Since the tracer magnetization dynamics are tied to the hydrodynamic mobility via the Brownian relaxation mechanism, MPI is also capable of mapping the local environment during the imaging process. Since the influence of viscosity or temperature on the harmonic spectrum is very complicated, we used magnetic particle spectroscopy (MPS) as an integral measurement technique to investigate the relationships. We studied MPS spectra as function of both viscosity and temperature on model particle systems. With multispectral MPS, we also developed an empirical tool for treating more complex scenarios via a calibration approach. We demonstrate that MPS/MPI are powerful methods for studying particle-matrix interactions in complex media.

Statins are popular drugs widely prescribed to control hypercholesterolaemia and to prevent cardiovascular diseases. Synthetic statins constitute a group of pharmaceuticals which are very sensitive to exposure to light in both UVA and UVB ranges. Light, by causing drugs degradation, can essentially change their pharmaceutical properties leading even to the loss of therapeutic activity and/or to the formation of deleterious photoproducts. Drugs which exhibit photochemical reactivity may elicit undesired adverse effects. A detailed understanding of mechanisms involved in molecular basis of these effects origin is very important for evaluating the photobiological risk associated with therapy in which drugs prone to exposure to light are involved. In this work we critically discussed finding regarding the mechanisms of synthetic statins phototransformation. We showed inconsistency of some previously reported facts and revised earlier presented studies. We also completed the lack of information on pitavastatin photobehaviour. This all together resulted in proposal of new schemes for the statins photodecomposition. We reviewed data derived from both experimental and computational methods. Studies of photochemical problems by the use of theoretical methods enable getting insight into areas of some fascinating events that experimental techniques can touch only indirectly. Besides effect of light, phenomenon of statins’ sensitivity to pH and resulting implications were discussed. Statins undergo pH-dependent interconversion between their pharmacologically active hydroxy acid and inactive lactone forms, and it was shown that for both forms, drugs’ interactions should be considered. Knowledge of the statins interconversion mechanisms is important for understanding how differences in the structures of their molecules can affect the drugs’ activity.

Floppy molecules can be defined as molecules performing large amplitude vibrations (LAVs). There are different types of LAVs among which the most common are inversion and internal rotation. Molecules with LAVs have been of great interest for a very long time since their dynamic, geometry and molecular spectra were very often considered as a challenge. In the review, we present an outline of the history and development of various theoretical approaches concerning molecules with LAVs. Different types of LAVs are described with the emphasis on inversion tunneling (wagging) and internal rotation (torsion). Furthermore, strategies for building explicit and effective Hamiltonians are given and explained in detail using a hydrazine molecule, which is an exemplary molecule performing three LAVs—two inversions and one internal rotation. Since floppy molecules play a significant role in numerous areas as chemistry, pharmacy, astrophysics, biology, agriculture etc., we also provide an overview of their applications.

The pulp and paper industry is a highly energy-intensive and water-consuming industry. This industry is known for the utilization of a wide range of raw materials, containing cellulose fibers (generally wood, recycled paper, and agricultural residues), for the production of various grades of paper. There are several processes involved in the conversion of raw materials to the paper product such as raw material preparation, pulping, pulp washing and screening, bleaching, stock preparation, papermaking and chemical recovery. All the processes are facing issues regarding process efficiency, product quality, energy & water consumption, and cost and environment. There is a need for further improvement and upgrading the technologies but the scale of operations, technological obsolesce and cost of implementing new technologies are some of the major issues. The main thrust areas of pulp and paper processing require major interventions in the adoption of green and clean technologies.

Different nanomedicine devices that were developed during the recent years can be suitable candidates for their application in the treatment of various deadly diseases such as cancer. From all the explored devices, the nanoencapsulation of several anticancer medicines is a very promising approach to overcome some drawbacks of traditional medicines: administered dose of the drugs, drug toxicity, low solubility of drugs, uncontrolled drug delivery, resistance offered by the physiological barriers in the body to drugs, among others. In this chapter, the most important and recent progress in the encapsulation of anticancer medicines is examined: methods of preparation of distinct nanoparticles (inorganic nanoparticles, dendrimers, biopolymeric nanoparticles, polymeric micelles, liposomes, polymersomes, carbon nanotubes, quantum dots, and hybrid nanoparticles), drug loading and drug release mechanisms. Furthermore, the possible applications in cancer prevention, diagnosis, and cancer therapy of some of these nanoparticles have been highlighted.