Manipulating Excited State Reactivity and Selectivity Through Hydrogen Bonding – From Solid-State Reactivity to BrØnsted Acid Photocatalysis

Hydrogen bonding mediated control of photochemical reaction is highlighted with an eye towards the development of BrØnsted Acid mediated photocatalysis.

Pinpointing Photothermal Contribution in Photochemical Reaction on Plasmonic Gold Nanoparticles

Dimerization of PNTP to DMAB could be directly driven by the laser heating effect. In plasmonic photocatalysis, the conversion rate and the reaction rate highly depended on the GNP sizes....

Chemical Effects of Light and Photography

This article discusses the chemical and biological effects of light and photography. Light is a form of energy known as electromagnetic radiation, and its expression at wavelengths and the unit of measurement, nanometer, is considered a separate characteristic. It ranges from very short wavelength to long wavelength radiation. Visible (normal / sunlight) light is the band of radiation that our eyes can see. Under the influence of light, the following processes can occur: the attachment of atoms to molecules, dissociation, photochemical reaction, synthesis reaction. This article discusses light and its chemical effects, as well as photography. Keywords: Photosynthesis. Photography, electromagnetic radiation, synthesis, photography, xerography, photography, photochemistry, eosin, erythrosine, methylene film.

The development of luminescent solar concentrator-based photomicroreactors: a cheap reactor enabling efficient solar-powered photochemistry

Sunlight strikes our planet every day with more energy than we consume in an entire year. Therefore, many researchers have explored ways to efficiently harvest and use sunlight energy for the activation of organic molecules. However, implementation of this energy source in the large-scale production of fine chemicals has been mostly neglected. The use of solar energy for chemical transformations suffers from potential drawbacks including scattering, reflections, cloud shading and poor matches between the solar emission and absorption characteristics of the photochemical reaction. In this account, we provide an overview of our efforts to overcome these issues through the development of Luminescent Solar Concentrator-based PhotoMicroreactors (LSC-PM). Such reactors can efficiently convert solar energy with a broad spectral distribution to concentrated and wavelength-shifted irradiation which matches the absorption maximum of the photocatalyst. Hence, the use of these conceptually new photomicroreactors provides an increased solar light harvesting capacity, enabling efficient solar-powered photochemistry. Graphical abstract

Study on the Photochemical Reaction Process of 4-methyl-7-Hydroxycoumarin and Its Mechanism by Multi-Spectroscopic Technologies

The photochemical reaction process of 4-methyl-7-hydroxycoumarin (7H4MC) was studied by UV-Vis spectrometer and fluorescence spectroscopy. The results have shown that the characteristic peak of the UV-Vis spectra at 323 nm of 7H4MC undergoes a significant decrease in absorbance and a slight blue shift when was illuminated; the absorbance of the absorption peak at 279 nm rises, and there is a tendency for new peaks to appear. May be, there are structural changes or new materials generation. The addition of imidazole, VC, 3-indole methanol, GSH and other substances also have different effects on the photochemical reaction of 7H4MC. Among them, only imidazole has a certain inhibitory effect on the process of its photochemical reaction.

Vitamin D in the prevention and treatment of periodontal diseases: an integrative review

Introduction: Vitamin D is synthesized from 7-dehydrocholesterol during a photochemical reaction, under the effect of ultraviolet radiation on the skin, obtained from food. It is hydroxylated in the liver to 25-hydroxyvitamin D3 (25(OH)D3). It is an active metabolite, which maintains the balance of calcium and phosphorus concentration in the blood, in addition to helping bone remodeling. Vitamin D deficiency promotes rickets in children and osteoporosis in adults, with a risk of bone fracture. Vitamin D acts in the pathogenesis of periodontal diseases via immunomodulation, increases mineral density and reduces bone resorption, which is important in combating agents that cause periodontal diseases. Objectives: Evaluate the importance of vitamin D in the prevention and treatment of periodontal diseases. Methods: A search was carried out in the PubMed/Medline, Scopus, Scielo, Embase, Web of Science and Google Scholar databases on scientifically proven evidence on the subject. Results: The present review demonstrated the importance of vitamin D in the prevention and treatment of periodontitis and the consequences of its deficiency on the oral health of patients. Conclusion: Vitamin D plays an important role in oral homeostasis and vitamin deficiency results in periodontal disease.