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International Journal of Molecular... Dec 2022Light emission by living organisms in the visible spectrum range is called bioluminescence [...].
Light emission by living organisms in the visible spectrum range is called bioluminescence [...].
Topics: Luminescent Proteins; Luminescent Measurements
PubMed: 36613724
DOI: 10.3390/ijms24010281 -
Proceedings of the National Academy of... Jul 2016Energy transfer with an associated spin change of the donor and acceptor, Dexter energy transfer, is critically important in solar energy harvesting assemblies, damage...
Energy transfer with an associated spin change of the donor and acceptor, Dexter energy transfer, is critically important in solar energy harvesting assemblies, damage protection schemes of photobiology, and organometallic opto-electronic materials. Dexter transfer between chemically linked donors and acceptors is bridge mediated, presenting an enticing analogy with bridge-mediated electron and hole transfer. However, Dexter coupling pathways must convey both an electron and a hole from donor to acceptor, and this adds considerable richness to the mediation process. We dissect the bridge-mediated Dexter coupling mechanisms and formulate a theory for triplet energy transfer coupling pathways. Virtual donor-acceptor charge-transfer exciton intermediates dominate at shorter distances or higher tunneling energy gaps, whereas virtual intermediates with an electron and a hole both on the bridge (virtual bridge excitons) dominate for longer distances or lower energy gaps. The effects of virtual bridge excitons were neglected in earlier treatments. The two-particle pathway framework developed here shows how Dexter energy-transfer rates depend on donor, bridge, and acceptor energetics, as well as on orbital symmetry and quantum interference among pathways.
PubMed: 27382185
DOI: 10.1073/pnas.1517189113 -
The Journal of Investigative Dermatology Jul 1976The history and origin of the science of photobiology are reviewed. Interest in the biologic effects of light gradually increased, beginning with the discovery of... (Review)
Review
The history and origin of the science of photobiology are reviewed. Interest in the biologic effects of light gradually increased, beginning with the discovery of ultraviolet and infrared radiation early in the 19th century. The basis of experimental photobiology was laid by the studies of Raab and Tappeiner on photodynamic action and the early uses of phototherapy by Finsen and Dorno. The discovery of the association of porphyrins with some light-related skin diseases and of the capability of chemical agents such as coal tar and bergamot to induce phototoxic contact dermatitis resulted in a flurry of clinical investigations leading to better understanding of the processes of phototoxicity and photoallergy. The early epidemiologic studies of Unna and Dubreuilh relating solar radiation exposure to the formation of actinic keratoses and non-melanoma skin cancer were experimentally confirmed in animals by Findlay, Roffo, and Blum. In the most recent quarter century (1950-1975), cellular and molecular photobiology has been refined. The studies on photochemistry of nucleic acid and of damage and repair mechanisms in DNA have set the stage for understanding the basic processes of biologic effects of light and promise the development of useful applications of specifically directed phototherapy and prevention of such light-induced diseases as skin cancer.
Topics: Animals; DNA; DNA Repair; Erythema; Europe; History, 19th Century; History, 20th Century; Humans; International Cooperation; Light; Molecular Biology; Photochemistry; Photosensitivity Disorders; Phototherapy; RNA; Skin; Skin Diseases; Skin Neoplasms; Skin Physiological Phenomena; Skin Pigmentation; Ultraviolet Rays
PubMed: 778294
DOI: 10.1111/1523-1747.ep12513042 -
Photochemistry and Photobiology Nov 2015Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science,... (Review)
Review
Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores.
Topics: DNA Repair; Molecular Structure; Photobiology; Photochemistry; Spores, Bacterial; Thymine; Ultraviolet Rays
PubMed: 26265564
DOI: 10.1111/php.12506 -
Journal of the American Academy of... Feb 2021Phototherapy is a safe and effective treatment for many dermatologic conditions. With the advent of novel biologics and small molecule inhibitors, it is important to... (Review)
Review
Phototherapy is a safe and effective treatment for many dermatologic conditions. With the advent of novel biologics and small molecule inhibitors, it is important to critically evaluate the role of phototherapy in dermatology. Surveys have shown that many dermatology residency programs do not dedicate time to teaching residents how to prescribe or administer phototherapy. Limitations of phototherapy include access to a center, time required for treatments, and insurance approval. Home phototherapy, a viable option, is also underused. However, it should be emphasized that modern phototherapy has been in use for over 40 years, has an excellent safety profile, and does not require laboratory monitoring. It can be safely combined with many other treatment modalities, including biologics and small molecule inhibitors. In addition, phototherapy costs significantly less than these novel agents. Dermatologists are the only group of physicians who have the expertise and proper training to deliver this treatment modality to our patients. Therefore, to continue to deliver high-quality, cost-effective care, it is imperative that phototherapy be maintained as an integral part of the dermatology treatment armamentarium.
Topics: Biological Factors; Cost-Benefit Analysis; Dermatology; History, 20th Century; History, 21st Century; Humans; Phototherapy; Practice Patterns, Physicians'; Skin Diseases; Treatment Outcome
PubMed: 32339702
DOI: 10.1016/j.jaad.2020.04.095 -
Plant Physiology Jun 2018
Topics: Arabidopsis Proteins; DNA-Binding Proteins; Light; Photobiology; Photoreceptors, Plant; Plant Physiological Phenomena; Signal Transduction
PubMed: 29899051
DOI: 10.1104/pp.18.00240 -
Molecules (Basel, Switzerland) Dec 2020
Topics: Carotenoids; Chlorophyll; Fluorescent Dyes; Humans; Molecular Probes; Photobiology; Photochemotherapy; Photosensitizing Agents; Sunlight
PubMed: 33287262
DOI: 10.3390/molecules25235707 -
International Journal of Hyperthermia :... 2018Thermography-controlled, water-filtered infrared-A (wIRA) is a novel, effective and approved heating technique listed in the ESHO quality assurance guidelines for... (Review)
Review
Thermography-controlled, water-filtered infrared-A (wIRA) is a novel, effective and approved heating technique listed in the ESHO quality assurance guidelines for superficial hyperthermia clinical trials (2017). In order to assess the special features and the potential of wIRA-hyperthermia (wIRA-HT), detailed and updated information about its physical and photobiological background is presented. wIRA allows for (a) application of high irradiances without skin pain and acute grade 2-4 skin toxicities, (b) prolonged, therapeutically relevant exposure times using high irradiances (150-200 mW/cm) and (c) faster and deeper heat extension within tissues. The deeper radiative penetration depth is mainly caused by forward Mie-scattering. At skin surface temperatures of 42-43 °C, the effective heating depth is 15 mm (T ≥ 40 °C) and 20 mm (T ≥ 39.5 °C). Advantages of wIRA include its contact-free energy input, easy power steering by a feed-back loop, extendable treatment fields, real-time and noninvasive surface temperature monitoring with observation of dynamic changes during HT, and - if necessary - rapid protection of temperature-sensitive structures. wIRA makes the compliant heating of ulcerated and/or bleeding tumors possible, allows for HT of irregularly shaped and diffusely spreading tumors, is independent of individual body contours, allows for very short 'transits' between HT and RT (1-4 min) or continuous heating between both therapeutic interventions. New treatment options for wIRA-HT may include malignant melanoma, vulvar carcinoma, skin metastases of different primary tumors, cutaneous T-and B-cell lymphoma, large-area hemangiomatosis, inoperable squamous cell, basal cell and eccrine carcinoma of the skin with depth extensions ≤20 mm.
Topics: Humans; Hyperthermia, Induced; Infrared Rays; Neoplasms; Water
PubMed: 29745269
DOI: 10.1080/02656736.2018.1469169 -
Topics in Current Chemistry (Cham) Mar 2022In recent years, photoactive proteins such as rhodopsins have become a common target for cutting-edge research in the field of optogenetics. Alongside wet-lab research,... (Review)
Review
In recent years, photoactive proteins such as rhodopsins have become a common target for cutting-edge research in the field of optogenetics. Alongside wet-lab research, computational methods are also developing rapidly to provide the necessary tools to analyze and rationalize experimental results and, most of all, drive the design of novel systems. The Automatic Rhodopsin Modeling (ARM) protocol is focused on providing exactly the necessary computational tools to study rhodopsins, those being either natural or resulting from mutations. The code has evolved along the years to finally provide results that are reproducible by any user, accurate and reliable so as to replicate experimental trends. Furthermore, the code is efficient in terms of necessary computing resources and time, and scalable in terms of both number of concurrent calculations as well as features. In this review, we will show how the code underlying ARM achieved each of these properties.
Topics: Rhodopsin
PubMed: 35291019
DOI: 10.1007/s41061-022-00374-w -
The Journal of Investigative Dermatology Jul 2013
Review
Topics: Animals; Humans; Immune Tolerance; Photobiology; Skin; Skin Neoplasms; Ultraviolet Rays
PubMed: 23820723
DOI: 10.1038/skinbio.2013.177