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https://www.readbyqxmd.com/read/27849028/evidences-for-cooperative-resonance-assisted-hydrogen-bonds-in-protein-secondary-structure-analogs
#1
Yu Zhou, Geng Deng, Yan-Zhen Zheng, Jing Xu, Hamad Ashraf, Zhi-Wu Yu
Cooperative behaviors of the hydrogen bonding networks in proteins have been discovered for a long time. The structural origin of this cooperativity, however, is still under debate. Here we report a new investigation combining excess infrared spectroscopy and density functional theory calculation on peptide analogs, represented by N-methylformamide (NMF) and N-methylacetamide (NMA). Interestingly, addition of the strong hydrogen bond acceptor, dimethyl sulfoxide, to the pure analogs caused opposite effects, namely red- and blue-shift of the N-H stretching infrared absorption in NMF and NMA, respectively...
November 16, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27662784/mechanisms-of-phosphene-generation-in-ocular-proton-therapy-as-related-to-space-radiation-exposure
#2
D Chuard, V Anthonipillai, R Dendale, C Nauraye, E Khan, C Mabit, L De Marzi, L Narici
Particle therapy provides an opportunity to study the human response to space radiation in ground-based facilities. On this basis, a study of light flashes analogous to astronauts' phosphenes reported by patients undergoing ocular proton therapy has been undertaken. The influence of treatment parameters on phosphene generation was investigated for 430 patients treated for a choroidal melanoma at the proton therapy centre of the Institut Curie (ICPO) in Orsay, France, between 2008 and 2011. 60% of them report light flashes, which are predominantly (74%) blue...
August 2016: Life Sciences in Space Research
https://www.readbyqxmd.com/read/27626383/a-blue-light-photoreceptor-mediates-the-feedback-regulation-of-photosynthesis
#3
Dimitris Petroutsos, Ryutaro Tokutsu, Shinichiro Maruyama, Serena Flori, Andre Greiner, Leonardo Magneschi, Loic Cusant, Tilman Kottke, Maria Mittag, Peter Hegemann, Giovanni Finazzi, Jun Minagawa
In plants and algae, light serves both as the energy source for photosynthesis and a biological signal that triggers cellular responses via specific sensory photoreceptors. Red light is perceived by bilin-containing phytochromes and blue light by the flavin-containing cryptochromes and/or phototropins (PHOTs), the latter containing two photosensory light, oxygen, or voltage (LOV) domains. Photoperception spans several orders of light intensity, ranging from far below the threshold for photosynthesis to values beyond the capacity of photosynthetic CO2 assimilation...
September 14, 2016: Nature
https://www.readbyqxmd.com/read/27607687/leaky-mode-waveguide-modulators-with-high-deflection-angle-for-use-in-holographic-video-displays
#4
Kamran Qaderi, Daniel E Smalley
Film display holograms typically diffract light over a wide enough view-angle to be viewed, directly, without intervening optics. However, all holographic video displays (with the exception of eye-tracked systems) must use optics beyond the hologram surface to overcome the challenges of small display extent and low diffraction angle by using some form of demagnification and derotation (i.e. angle magnification and optical multiplexing). We report a leaky mode waveguide spatial light modulator with sufficiently high angular diffraction to obviate the need for demagnification in scanned aperture systems...
September 5, 2016: Optics Express
https://www.readbyqxmd.com/read/27594835/flash-and-freeze-coordinating-optogenetic-stimulation-with-rapid-freezing-to-visualize-membrane-dynamics-at-synapses-with-millisecond-resolution
#5
Shigeki Watanabe
Electron microscopy depicts subcellular structures at synapses exquisitely but only captures static images. To visualize membrane dynamics, we have developed a novel technique, called flash-and-freeze, which induces neuronal activity with a flash of light and captures the membrane dynamics by rapid freezing. For characterizing membrane movements during synaptic transmission, a light-sensitive cation channel, channelrhodopsin, is heterologously expressed in mouse hippocampal neurons or in Caenorhabditis elegans motor neurons...
2016: Frontiers in Synaptic Neuroscience
https://www.readbyqxmd.com/read/27485220/carotenoids-and-photosynthesis
#6
Hideki Hashimoto, Chiasa Uragami, Richard J Cogdell
Carotenoids are ubiquitous and essential pigments in photosynthesis. They absorb in the blue-green region of the solar spectrum and transfer the absorbed energy to (bacterio-)chlorophylls, and so expand the wavelength range of light that is able to drive photosynthesis. This is an example of singlet-singlet energy transfer, and so carotenoids serve to enhance the overall efficiency of photosynthetic light reactions. Carotenoids also act to protect photosynthetic organisms from the harmful effects of excess exposure to light...
2016: Sub-cellular Biochemistry
https://www.readbyqxmd.com/read/27446941/influence-of-the-environment-on-body-temperature-of-racing-greyhounds
#7
Jane McNicholl, Gordon S Howarth, Susan J Hazel
Heat strain is a potential risk factor for racing greyhounds in hot climates. However, there have been limited studies into the incidence of heat strain (when excess heat causes physiological or pathological effects) in racing greyhounds. The aim of this study was to determine if heat strain occurs in racing greyhounds, and, if so, whether environmental factors (e.g., ambient temperature and relative humidity) or dog-related factors (e.g., sex, bodyweight, color) are associated with the risk of heat strain...
2016: Frontiers in Veterinary Science
https://www.readbyqxmd.com/read/27099081/sunglass-filter-transmission-and-its-operational-effect-in-solar-protection-for-civilian-pilots
#8
Adrian C Chorley, Andrey Lyachev, Michael P Higlett, Marina Khazova, Martin J Benwell, Bruce J W Evans
INTRODUCTION: The ocular effects of excess solar radiation exposure are well documented. Recent evidence suggests that ocular ultraviolet radiation (UVR) exposure to professional pilots may fall outside international guideline limits unless eye protection is used. Nonprescription sunglasses should be manufactured to meet either international or national standards. The mean increase in UVR and blue light hazards at altitude has been quantified and the aim of this research was to assess the effectiveness of typical pilot sunglasses in reducing UVR and blue light hazard exposure in flight...
May 2016: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/27037590/the-color-of-mass-culture-spectral-characteristics-of-a-shallow-water-column-through-shade-limited-algal-growth-dynamics-1
#9
Christopher D Hewes
It is envisioned that mass algal cultivation for commercial biofuels production will entail the use of large raceway pond systems, which typically have shade-limited photosynthetic growth within depths of 20-30 cm. The attenuation of light and spectral qualities of red, green, and blue wavelengths in a 20-cm water column as a function of Chl-a concentration during exponential and linear phases of growth dynamics for the marine diatom Thalassiosira pseudonana was examined under laboratory conditions. While photosynthetically available radiation (PAR) was in excess throughout the water column during the phase of exponential growth, PAR became rate limiting differently for red, green, and blue wavelengths during the phase of linear growth...
April 2016: Journal of Phycology
https://www.readbyqxmd.com/read/27011280/light-induced-oil-globule-migration-in-haematococcus-pluvialis-chlorophyceae
#10
Ehud Peled, Uri Pick, Aliza Zarka, Eyal Shimoni, Stefan Leu, Sammy Boussiba
Astaxanthin-rich oil globules in Haematococcus pluvialis display rapid light-induced peripheral migration that is unique to this organism and serves to protect the photosynthetic system from excessive light. We observed rapid light-induced peripheral migration that is associated with chlorophyll fluorescence quenching, whereas the recovery was slow. A simple assay to follow globule migration, based on chlorophyll fluorescence level has been developed. Globule migration was induced by high intensity blue light, but not by high intensity red light...
October 2012: Journal of Phycology
https://www.readbyqxmd.com/read/26906429/glutathione-reductase-2-maintains-the-function-of-photosystem-ii-in-arabidopsis-under-excess-light
#11
Shunhua Ding, Rui Jiang, Qingtao Lu, Xiaogang Wen, Congming Lu
Glutathione reductase plays a crucial role in the elimination of H(2)O(2) molecules via the ascorbate-glutathione cycle. In this study, we used transgenic Arabidopsis plants with decreased glutathione reductase 2 (GR2) levels to investigate whether this GR2 activity protects the photosynthetic machinery under excess light. The transgenic plants were highly sensitive to excess light and accumulated high levels of H(2)O(2). Photosystem II (PSII) activity was significantly decreased in transgenic plants. Flash-induced fluorescence relaxation and thermoluminescence measurements demonstrated inhibition of electron transfer between Q(A) and Q(B) and decreased redox potential of Q(B) in transgenic plants...
June 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/26884406/collagenoma-in-an-african-clawed-frog-xenopus-laevis
#12
Jessica M Johnston, Blythe H Philips, Anthony J Carty, Peter S Klein, Angela K Brice
A 3-y-old female Xenopus laevis was reported for a gray mass on the abdomen. The frog was used for egg collection and was otherwise experimentally naïve. On physical exam, the frog was bright and active and had a firm, gray, lobulated mass (1.5 cm × 0.5 cm × 0.5 cm) in the cutaneous tissue of the left lateral abdomen. An excisional biopsy was performed under anesthesia, and the entire mass was removed and processed for histopathology. Microscopically, the dermis was greatly expanded by connective tissue with a marked decrease in the number of glands, and occasional degenerative glands were present...
February 2016: Comparative Medicine
https://www.readbyqxmd.com/read/26867613/automatic-chloroplast-movement-analysis
#13
Henrik Johansson, Mathias Zeidler
In response to low or high intensities of light, the chloroplasts in the mesophyll cells of the leaf are able to increase or decrease their exposure to light by accumulating at the upper and lower sides or along the side walls of the cell respectively. This movement, regulated by the phototropin blue light photoreceptors phot1 and phot2, results in a decreased or increased transmission of light through the leaf. This way the plant is able to optimize harvesting of the incoming light or avoid damage caused by excess light...
2016: Methods in Molecular Biology
https://www.readbyqxmd.com/read/26670830/measuring-in-vivo-free-radical-production-by-the-outer-retina
#14
Bruce A Berkowitz, Bryce X Bredell, Christopher Davis, Marijana Samardzija, Christian Grimm, Robin Roberts
PURPOSE: Excessive and continuously produced free radicals in the outer retina are implicated in retinal aging and the pathogenesis of sight-threatening retinopathies, yet measuring outer retinal oxidative stress in vivo remains a challenge. Here, we test the hypothesis that continuously produced paramagnetic free radicals from the outer retina can be measured in vivo using high-resolution (22-μm axial resolution) 1/T1magnetic resonance imaging (MRI) without and with a confirmatory quench (quench-assisted MRI)...
December 2015: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/26625615/-led-lighting-as-a-factor-for-the-stimulation-of-the-hormone-system
#15
V N Deynego, V A Kaptsov
There are considered questions of non-visual effects of blue LED light sources on hormonal systems (cortisol, glucose, insulin) providing the high human performance. In modern conditions hygiene strategy for child and adolescent health strategy was shown to be replaced by a strategy of light stimulation of the hormonal profile. There was performed a systematic analysis of the axis "light stimulus-hypothalamus-pituitary-adrenals-cortisol-glucose-insulin". The elevation of the content of cortisol leads to the increase of the glucose level in the blood and the stimulation of the production of insulin, which can, like excessive consumption of food, give rise to irreversible decline in the number of insulin receptors on the cell surface, and thus--to a steady reduction in the ability of cells to utilize glucose, i...
September 2015: Gigiena i Sanitariia
https://www.readbyqxmd.com/read/26597112/scleral-cross-linking-by-riboflavin-and-blue-light-application-in-young-rabbits-damage-threshold-and-eye-growth-inhibition
#16
Hans Peter Iseli, Nicole Körber, Christian Koch, Anett Karl, Anja Penk, Daniel Huster, Andreas Reichenbach, Peter Wiedemann, Mike Francke
BACKGROUND: Scleral cross-linking (SXL) by riboflavin and light application has been introduced as a possible treatment to increase scleral tissue stiffness and to inhibit excessive axial elongation of highly myopic eyes. We evaluated an ocular tissue damage threshold for blue light irradiation, and used SXL treatment to induce eye growth inhibition. METHODS: The sclera of 3-week-old rabbits (39 pigmented and 15 albino rabbits) were treated with different blue light intensities (450 ± 50 nm) and riboflavin...
January 2016: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/26589689/preventive-effect-of-vaccinium-uliginosum-l-extract-and-its-fractions-on-age-related-macular-degeneration-and-its-action-mechanisms
#17
Sun-Myung Yoon, Bom-Lee Lee, Yuan-Ri Guo, Se-Young Choung
Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness among the elderly. Although the pathogenesis of this disease remains still obscure, several researchers have report that death of retinal pigmented epithelium (RPE) caused by excessive accumulation of A2E is crucial determinants of AMD. In this study, the preventive effect of Vaccinium uliginosum L. (V.U) extract and its fractions on AMD was investigated in blue light-irradiated human RPE cell (ARPE-19 cells). Blue light-induced RPE cell death was significantly inhibited by the treatment of V...
January 2016: Archives of Pharmacal Research
https://www.readbyqxmd.com/read/26502064/high-power-efficiency-solution-processed-blue-phosphorescent-organic-light-emitting-diodes-using-exciplex-type-host-with-a-turn-on-voltage-approaching-the-theoretical-limit
#18
Xinxin Ban, Kaiyong Sun, Yueming Sun, Bin Huang, Shanghui Ye, Min Yang, Wei Jiang
Three solution-processable exciplex-type host materials were successfully designed and characterized by equal molar blending hole transporting molecules with a newly synthesized electron transporting material, which possesses high thermal stability and good film-forming ability through a spin-coating technique. The excited-state dynamics and the structure-property relationships were systematically investigated. By gradually deepening the highest occupied molecular orbital (HOMO) level of electron-donating components, the triplet energy of exciplex hosts were increased from 2...
November 18, 2015: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/26481715/narrow-band-imaging-and-bladder-cancer-when-and-how
#19
Angelo Naselli, Paolo Puppo
Narrow band imaging (NBI) is an optical enhancement technology for endoscopy. NBI works filtering the standard white light in two bandwidths of illumination of 415 nm, blue, and 540 nm, green. As a result, capillaries on mucosal surface appear brown and veins in connective subepithelial layer cyan, enhancing the contrast among epithelial, subepithelial tissue and its vascularisation. Given that it is a filter, it is safe, does not need any kind of instillation and the vision modality can be switched from NBI to white light and vice versa without any limitations of time...
October 2015: Urologia
https://www.readbyqxmd.com/read/26450475/calcium-requirements-from-dairy-foods-in-france-can-be-met-at-low-energy-and-monetary-cost
#20
COMPARATIVE STUDY
Adam Drewnowski, Wesley Tang, Rémi Brazeilles
Inadequate Ca intakes are a concern for global public health. In France, most dietary Ca is provided by dairy products: milks, fermented milks (mostly yogurts), dairy desserts and cheeses. The present dairy database (n 837) included milks (n 101), fermented milks, yogurts and other fresh dairy products (n 326), desserts (n 162) and a wide variety of cheeses (n 248). Energy and nutrient values were obtained from industry sources and the French national nutrient composition database. Retail prices were from Paris supermarkets...
December 14, 2015: British Journal of Nutrition
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