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Riboflavin, known as vitamin B2, belongs to the class of water-soluble vitamins with redox, fluorescence, and photosensitizing properties. Riboflavin contains a fragment of 7,8-dimethyl-10-(1′-D-ribityl) isoalloxazine with a system of conjugated double bonds that is are responsible for its photochemical properties. In the presence of light and oxygen, riboflavin generates reactive oxygen species that can be further involved in the oxidation of biological molecules such as amino acids, proteins, nucleotides, and lipids. The chapter focuses on the photochemical application of riboflavin in (1) cross-linking of structural proteins such as collagen and (2) synthesis of hydrogels. The involvement of riboflavin in such processes has already found application in medicine, especially in the treatment of ophthalmic diseases and in tissue engineering.

Hydrogels represent heterogeneous systems that consist of a large amount of water retained by a three-dimensional network. The hydrogel network is the result of assembly through physical interactions or chemical cross-linking of polymers or small molecules. The applications of hydrogels (water purification, tissue regeneration, therapeutic delivery, bio-detection or bio-imaging, etc.) depend on their physicochemical properties and structural features. Although electron microscopy and viscoelastic measurements provide general information about a gel material, the spectroscopic methods complement these methods and also afford a deep insight into the gel structure. In this chapter, the applications of several spectroscopic methods for characterizing polymeric or supramolecular hydrogels are discussed. Thus, this review highlights the particular application of vibrational spectroscopy, circular dichroism, fluorescence (these providing information on assembly in the network), interactions that occur between network and solvent (water), pulsed-field gradient NMR (determination of mesh size) and EPR spectroscopy (a method that can provide extensive information regarding the assembly process, diffusion and release).

This study qualitatively explored (1) whether general opportunities for play at the neighbourhood level were related to children’s social competence development, and (2) whether children’s experience in peer-led play, rather than adult-led play (again at the neighbourhood level) could further explain children’s social competence development. For the first part of this study, descriptive information was gathered on the following seven indicators of play in six British Columbian neighbourhoods: community recreational resources, children’s recreational programs, access to sports, community programs funded by the government, private recreation and sports, childcare providers, and Family Places. For the second part of this study, 24 community informants were interviewed using semi-structured interviews which covered the following seven play themes: structured, unstructured, adult-led, peer-led, access, general philosophy, and opportunities for general social interaction. Results from this study do not suggest that opportunities for play, peer- or adult-led, help explain neighbourhood levels of children’s social competence.

Two mononuclear complexes [(Et3NH)[M(hfac)2L] (M = Ni, 1; Zn, 2) have been synthesized using a nitronyl-nitroxide radical substituted nitrophenol, that is 2-(2-hydroxy-3-methoxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl, HL, as a proligand. The crystal structures of 1 and 2 have been solved and indicate an octahedral coordination geometry of the metal ions. The magnetic behavior for 1 is characterized by a strong antiferromagnetic metal–radical interaction (J = −351 ± 1 cm−1; H = −JSNiSRad). This exchange interaction was rationalized by DFT calculations. The EPR spectra recorded in both solution and solid state at 120 K confirm the S = ½ ground state for 1.

Two mononuclear complexes [(Et3NH)[M(hfac)2L] (M = Ni, 1; Zn, 2) have been synthesized using a nitronyl-nitroxide radical substituted nitrophenol, that is 2-(2-hydroxy-3-methoxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl, HL, as a proligand. The crystal structures of 1 and 2 have been solved and indicate an octahedral coordination geometry of the metal ions. The magnetic behavior for 1 is characterized by a strong antiferromagnetic metal–radical interaction (J = −351 ± 1 cm−1; H = −JSNiSRad). This exchange interaction was rationalized by DFT calculations. The EPR spectra recorded in both solution and solid state at 120 K confirm the S = ½ ground state for 1.

This study qualitatively explored (1) whether general opportunities for play at the neighbourhood level were related to children's social competence development, and (2) whether children's experience in peer-led play, rather than adult-led play (again at the neighbourhood level) could further explain children's social competence development. For the first part of this study, descriptive information was gathered on the following seven indicators of play in six British Columbian neighbourhoods: community recreational resources, children's recreational programs, access to sports, community programs funded by the government, private recreation and sports, childcare providers, and Family Places. For the second part of this study, 24 community informants were interviewed using semi-structured interviews which covered the following seven play themes: structured, unstructured, adult-led, peer-led, access, general philosophy, and opportunities for general social interaction. Results from this study do not suggest that opportunities for play, peer- or adult-led, help explain neighbourhood levels of children's social competence.

Cyclodextrins are natural cyclic oligosaccharides with a cone shape delimiting a hydrophobic cavity. The rims of cyclodextrins can be functionalized in order to improve their properties. Based on this, cyclodextrins can be linked to polymer chains, which further allows the tuning of the polymer properties. This review describes the methods of polymer functionalization with cyclodextrins and highlights the changes in the physicochemical properties of these materials. This chapter is focused on polymers in solution and in gel states. Cyclodextrin-based polymers are evaluated by various physicochemical methods, such as rheology, calorimetry, and spectroscopy (electron paramagnetic resonance, fluorescence, nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), etc.). Both natural and synthetic polymers are considered in this chapter.