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Robert H James, Robert J Landry, Bennett N Walker, Ilko K Ilev
The authors evaluated the potential for ocular damage from optical radiation emitted by Light Emitting Diode (LED) based lamps used for general illumination. Ten LED lamps were randomly selected off the shelf from a local home improvement store. The LEDs were behind diffusers in half of these lamps, while in the other half, the LEDs were clearly visible. In addition, a battery powered LED lantern having a LED source behind a diffuser was measured. The optical radiation emissions from two common incandescent lamps were also measured to compare the relative hazards of LED and incandescent lamps...
January 2017: Health Physics
Peter Wolf, Frank de Gruijl
No abstract text is available yet for this article.
December 2016: Experimental Dermatology
Giorgio Perrella, Eirini Kaiserli
Light is a powerful stimulus regulating many aspects of plant development and phenotypic plasticity. Plants sense light through the action of specialized photoreceptor protein families that absorb different wavelengths and intensities of light. Recent discoveries in the area of photobiology have uncovered photoreversible changes in nuclear organization correlated with transcriptional regulation patterns that lead to de-etiolation and photoacclimation. Novel signalling components bridging photoreceptor activation with chromatin remodelling and regulation of gene expression have been discovered...
November 4, 2016: New Phytologist
Karl P Gerhardt, Evan J Olson, Sebastian M Castillo-Hair, Lucas A Hartsough, Brian P Landry, Felix Ekness, Rayka Yokoo, Eric J Gomez, Prabha Ramakrishnan, Junghae Suh, David F Savage, Jeffrey J Tabor
In optogenetics, researchers use light and genetically encoded photoreceptors to control biological processes with unmatched precision. However, outside of neuroscience, the impact of optogenetics has been limited by a lack of user-friendly, flexible, accessible hardware. Here, we engineer the Light Plate Apparatus (LPA), a device that can deliver two independent 310 to 1550 nm light signals to each well of a 24-well plate with intensity control over three orders of magnitude and millisecond resolution. Signals are programmed using an intuitive web tool named Iris...
November 2, 2016: Scientific Reports
A Pérez-Ferriols, M Barnadas, J Gardeazábal, D de Argila, J M Carrascosa, P Aguilera, A Giménez-Arnau, T Rodríguez-Granados, M V de Gálvez, J Aguilera
BACKGROUND: Solar urticaria is a chronic inducible urticaria also classified as an idiopathic dermatosis. The objective of this paper is to define the phenotypic characteristics of solar urticaria and to evaluate its incidence. MATERIAL AND METHOD: This was a retrospective multicenter study in which data were gathered on the epidemiology and clinical, photobiologic, laboratory, and therapeutic characteristics of solar urticaria. RESULTS: A total of 224 patients (141 women and 83 men) were included from 9 photobiology units...
October 25, 2016: Actas Dermo-sifiliográficas
Federico Melaccio, María Del Carmen Marín, Alessio Valentini, Fabio Montisci, Silvia Rinaldi, Marco Cherubini, Xuchun Yang, Yoshitaka Kato, Michael Stenrup, Yoelvis Orozco-Gonzalez, Nicolas Ferré, Hoi Ling Luk, Hideki Kandori, Massimo Olivucci
We report on a prototype protocol for the automatic and fast construction of congruous sets of QM/MM models of rhodopsin-like photoreceptors and of their mutants. In the present implementation the information required for the construction of each model is essentially a crystallographic structure or a comparative model complemented with information on the protonation state of ionizable side-chains and distributions of external counterions. Starting with such information a model formed by a fixed environment system, a flexible cavity system and a chromophore system is automatically generated...
October 25, 2016: Journal of Chemical Theory and Computation
Milene N O Moritz, Joyce L S Gonçalves, Irwin A P Linares, Janice R Perussi, Kleber T de Oliveira
An amphiphilic chlorin derivative (CHL-T) was prepared from methylpheophorbide a (CHL) and 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRISMA(®)). The new chlorin was compared to other dyes (CHL and Hypericin) in relation to photophysical and photobiological activities in tumor and non-tumor cell lines. Cytotoxicity and cell death target were determined to evaluate the CHL-T efficiency, comparing to the precursor CHL and to the well-known dye hypericin (HY). All of the studied compounds exhibited absorption bands in the therapeutic window and presented a small fluorescence quantum yield compared to the reference dye (rhodamine B)...
October 18, 2016: Photodiagnosis and Photodynamic Therapy
Natalie C Sadler, Hans C Bernstein, Matthew R Melnicki, Moiz A Charania, Eric A Hill, Lindsey N Anderson, Matthew E Monroe, Richard D Smith, Alexander S Beliaev, Aaron T Wright
: Photobiologically synthesized hydrogen (H2) gas is carbon neutral to produce and clean to combust, making it an ideal biofuel. Cyanothece sp. strain ATCC 51142 is a cyanobacterium capable of performing simultaneous oxygenic photosynthesis and H2 production, a highly perplexing phenomenon because H2 evolving enzymes are O2 sensitive. We employed a system-level in vivo chemoproteomic profiling approach to explore the cellular dynamics of protein thiol redox and how thiol redox mediates the function of the dinitrogenase NifHDK, an enzyme complex capable of aerobic hydrogenase activity...
December 15, 2016: Applied and Environmental Microbiology
Xiao-Jing Song, Shu-You Wang, Yin-Long Li, Dong Zhang
The objective of this study was to investigate the spectra characteristics (SC) at wavelengths of 400~1000 nm and 2.5~15.5 μm of pure moxa stick (MS) during its 25-minute burning process using new spectral imaging techniques. Spectral images were collected for the burning pure MS at 5, 10, 15, 20, and 25 min using hyperspectral imaging (HSI) and Fourier transform infrared spectroscopy (FTIR) for the first time. The results showed that, at wavelengths of 400~1000 nm, the spectral range of the cross section of MS burning was 750~980 nm; the peak position was 860 nm...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
Meltem Göksel, Mahmut Durmuş, Devrim Atilla
A series of phthalocyanine-peptide-quencher conjugates (6-9) were synthesized as photosensitizers for photodynamic therapy in cancer treatment. The photophysical, photochemical and photobiological properties of these activatable molecular beacons were also investigated in this study. For this purpose, the fluorescence, singlet oxygen and photodegradation quantum yields and fluorescence lifetime values of the compounds were determined in DMSO solutions. The phototoxicity and cytotoxicity of the systems were studied against the cervical cancer cell line named HeLa for an evaluation of their suitability for photodynamic therapy...
October 5, 2016: Photochemical & Photobiological Sciences
Raymond F Pauszek, Goutham Kodali, M Salim U Siddiqui, Robert J Stanley
Chromophoric biomolecules are exploited as reporters of a diverse set of phenomena, acting as internal distance monitors, environment and redox sensors, and as endogenous imaging probes. The extent to which they can be exploited is based on an accurate knowledge of their fundamental electronic properties. Arguably of greatest importance is a precise knowledge of the direction(s) of the absorption transition dipole moment(s) in the molecular frame of reference. Such is the case for flavins, fluorescent redox cofactors utilized for ground and excited state redox and photochemical processes...
September 29, 2016: Journal of the American Chemical Society
Kevin K Fuller, Robert A Cramer, Michael E Zegans, Jay C Dunlap, Jennifer J Loros
UNLABELLED: The given strain of Aspergillus fumigatus under study varies across laboratories, ranging from a few widely used "standards," e.g., Af293 or CEA10, to locally acquired isolates that may be unique to one investigator. Since experiments concerning physiology or gene function are seldom replicated by others, i.e., in a different A. fumigatus background, the extent to which behavioral heterogeneity exists within the species is poorly understood. As a proxy for assessing such intraspecies variability, we analyzed the light response of 15 A...
September 20, 2016: MBio
S-J Royer, M Galí, A S Mahajan, O N Ross, G L Pérez, E S Saltzman, R Simó
Emission of the trace gas dimethylsulphide (DMS) from the ocean influences the chemical and optical properties of the atmosphere, and the olfactory landscape for foraging marine birds, turtles and mammals. DMS concentration has been seen to vary across seasons and latitudes with plankton taxonomy and activity, and following the seascape of ocean's physics. However, whether and how does it vary at the time scales of meteorology and day-night cycles is largely unknown. Here we used high-resolution measurements over time and depth within coherent water patches in the open sea to show that DMS concentration responded rapidly but resiliently to mesoscale meteorological perturbation...
2016: Scientific Reports
A K Bauri, Sabine Foro, Quynh Nguyen Nhu Do
The title compound, C12H8O4, is a furan-ocoumarin [systematic name: 4-meth-oxy-7H-furo[3,2-g]chromen-7-one], which was isolated from the Indian herb T. stictocarpum. The mol-ecule is almost planar with an r.m.s. deviation of 0.024 Å for the hetero atoms of the fused-ring system. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional framework. There are offset π-π inter-actions present involving the coumarin moieties stacking along the a-axis direction [shortest inter-centroid distance = 3...
August 1, 2016: Acta Crystallographica. Section E, Crystallographic Communications
Dominic Deo Androga, Basar Uyar, Harun Koku, Inci Eroglu
For outdoor photobiological hydrogen production, the effective control of temperature in photobioreactors is a challenge. In this work, an internal cooling system for outdoor tubular photobioreactors was designed, built, and tested. The temperatures in the reactors with bacteria were consistently higher than those without bacteria, and were also strongly influenced by solar irradiation and ambient air temperature. The cooling protocol applied successfully kept the reactor temperatures below the threshold limit (38 °C) required for the bioprocess and provided a uniform distribution of temperature along the reactor tube length...
December 2016: Bioprocess and Biosystems Engineering
Kitae Kim, Soon-Kyeong Kwon, Jung-Hoon Yoon, Jihyun F Kim
Dokdonia spp. have been used for investigating the lifestyles of proteorhodopsin-containing photoheterotrophs and for understanding marine photobiology. Here, we report the complete genome sequence of Dokdonia donghaensis DSW-1(T) using the PacBio sequencing platform. It should provide a valuable resource for comparative genomic studies of marine life harboring microbial rhodopsins among others.
2016: Genome Announcements
Kuk-Youn Ju, Jeeun Kang, Jin Ho Chang, Jin-Kyu Lee
The contradictory biological function of eumelanin (photoprotection vs photosensitization) has long been a topic of debate in a wide range of disciplines such as chemistry, physics and biology. For understanding full spectrum of eumelanin's photobiological aspect, revealing how eumelanin's complex structural organization dictates its photophysical properties is critical step. Here, we report a practical approach to controlling the hierarchically assembled structure of natural eumelanin, which leads to disassembly of its structure into subunits and oxidized subunits, respectively...
September 12, 2016: Biomacromolecules
Christian Reichardt, Tariq Sainuddin, Maria Wächtler, Susan Monro, Stephan Kupfer, Julien Guthmuller, Stefanie Gräfe, Sherri McFarland, Benjamin Dietzek
The influence of ligand protonation on the photophysics of a ruthenium (Ru) dyad bearing the 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]-phenanthroline (ippy) ligand was investigated by time-resolved transient absorption spectroscopy. It was found that changes in the protonation state of the imidazole group led to changes in the electronic configuration of the lowest lying excited state. Formation of the fully deprotonated imidazole anion resulted in excited state signatures that were consistent with a low-lying intraligand (IL) triplet state...
August 18, 2016: Journal of Physical Chemistry. A
Damilola Fajuyigbe, Antony R Young
Terrestrial solar ultraviolet radiation (UVR) exerts both beneficial and adverse effects on human skin. Epidemiological studies show a lower incidence of skin cancer in people with pigmented skins compared to fair skins. This is attributed to photoprotection by epidermal melanin, as is the poorer vitamin D status of those with darker skins. We summarize a wide range of photobiological responses across different skin colours including DNA damage and immunosuppression. Some studies show the generally modest photoprotective properties of melanin, but others show little or no effect...
November 2016: Pigment Cell & Melanoma Research
Meltem Göksel
Zinc(II) phthalocyanine containing [2-(tert-butoxycarbonyl)amino]ethoxy and iodine groups (A and B), as well as their deprotected mono-amino and tri-iodine zinc(II) phthalocyanine (2) were obtained. This structure surrounds by substituents with functional groups. From this perspective it can be used a starting material for many reactions and applications, such as sonogashira coupling, carbodiimide coupling. An example of a first diversification reaction of this compound was obtained with conjugation of a biotin...
September 15, 2016: Bioorganic & Medicinal Chemistry
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