Read by QxMD icon Read

excessive blue light

Kotaro Kosuge, Ryutaro Tokutsu, Eunchul Kim, Seiji Akimoto, Makio Yokono, Yoshifumi Ueno, Jun Minagawa
Photosynthetic organisms are frequently exposed to light intensities that surpass the photosynthetic electron transport capacity. Under these conditions, the excess absorbed energy can be transferred from excited chlorophyll in the triplet state (3Chl*) to molecular O2 , which leads to the production of harmful reactive oxygen species. To avoid this photooxidative stress, photosynthetic organisms must respond to excess light. In the green alga Chlamydomonas reinhardtii , the fastest response to high light is nonphotochemical quenching, a process that allows safe dissipation of the excess energy as heat...
March 19, 2018: Proceedings of the National Academy of Sciences of the United States of America
Hamzah Mustak, Danica Fiaschetti, Adit Gupta, Robert Goldberg
Background: The eyebrow region presents challenges for filling: the skin is thick, the three-dimensional anatomy is complex and there is a predisposition towards fat atrophy and skeletonization with aging. Hyaluronic acid gel fillers are well known for their use in the periorbital region. We report our long-term experience with eyebrow filling over a period of five years. Methods: Twenty cases of periorbital eyebrow filling with hyaluronic acid gel fillers were followed up over a period of five years. The eyebrow filling was customized based on the patient's anatomical features in a three-dimensional plane...
February 2018: Journal of Clinical and Aesthetic Dermatology
Eimer Mary Tuite, Bengt Norden
The assembly of stacked dyes on DNA is of interest for electron transfer, light harvesting, sensing and catalysis applications. A combination of UV/vis absorption, linear dichroism (LD), and circular dichroism (CD) was applied to characterize thoroughly the aggregation with DNA of the phenothiazine dyes methylene blue, azure B, and thionine. Aggregates of each dye with [poly(dG-dC)]2 , [poly(dA-dT)]2 and calf thymus DNA were explored at high dye:DNA binding ratios, where excess dye groove-binds after all intercalation sites are filled...
February 26, 2018: Journal of Physical Chemistry. B
Shlomo Mehari, Daniel A Cohen, Daniel L Becerra, Shuji Nakamura, Steven P DenBaars
The benefits of utilizing transparent conductive oxide on top of a thin p-GaN layer for continuous-wave (CW) operation of blue laser diodes (LDs) were investigated. A very low operating voltage of 5.35 V at 10 kA/cm2 was obtained for LDs with 250 nm thick p-GaN compared to 7.3 V for LDs with conventional 650 nm thick p-GaN. An improved thermal performance was also observed for the thin p-GaN samples resulting in a 40% increase in peak light output power and a 32% decrease in surface temperature. Finally, a tradeoff was demonstrated between low operating voltage and increased optical modal loss in the indium tin oxide (ITO) with thinner p-GaN...
January 22, 2018: Optics Express
Şule Ayla, Gülden Tunalı, Bülent E Bilgiç, Kenan Sofuoğlu, A Arman Özdemir, Gamze Tanrıverdi, Semra Özdemir, B Cem Soner, Bahar Öztürk, Serçin Karahüseyinoğlu, Esra Güler Aslan, Ismail Seçkin
PURPOSE: Sperm processing (e.g., centrifugation) used in preparation for assisted reproduction can result in excessive generation of reactive oxygen species (ROS) and potential sperm damage. The use of antioxidants during sperm processing has been shown to prevent iatrogenic sperm damage, including DNA damage. In this study, we evaluated the effect of caffeic acid phenethyl ester (CAPE) on oxidative stress mediated sperm dysfunction and DNA damage. METHODS: Semen samples were obtained to liquefy at room temperature...
January 8, 2018: Acta Histochemica
Pelham A Keahey, Mathieu L Simeral, Kristofer J Schroder, Meaghan M Bond, Prince J Mtenthaonnga, Robert H Miros, Queen Dube, Rebecca R Richards-Kortum
Newborns are at increased risk of jaundice, a condition in which excess bilirubin accumulates in blood. Left untreated, jaundice can lead to neurological impairment and death. Jaundice resulting from unconjugated hyperbilirubinemia is easily treated with exposure to blue light, and phototherapy systems have been developed for low-resource settings; however, there are no appropriate solutions to diagnose and monitor jaundice in these settings. To address this need we present BiliSpec, a low-cost reader and disposable lateral flow card designed to measure the concentration of total bilirubin from several drops of blood at the point of care...
December 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yutaka Shibata, Ahmed Mohamed, Koichiro Taniyama, Kentaro Kanatani, Makiko Kosugi, Hiroshi Fukumura
Some mosses are extremely tolerant of drought stress. Their high drought tolerance relies on their ability to effectively dissipate absorbed light energy to heat under dry conditions. The energy dissipation mechanism in a drought-tolerant moss, Bryum argenteum, has been investigated using low-temperature picosecond time-resolved fluorescence spectroscopy. The results are compared between moss thalli samples harvested in Antarctica and in Japan. Both samples show almost the same quenching properties, suggesting an identical drought tolerance mechanism for the same species with two completely different habitats...
November 9, 2017: Photosynthesis Research
A K Barczak-Brzyżek, M Kiełkiewicz, P Gawroński, K Kot, M Filipecki, B Karpińska
Little is known about how plants deal with arthropod herbivores under the fluctuating light intensity and spectra which occur in natural environments. Moreover, the role of simultaneous stress such as excess light (EL) in the regulation of plant responses to herbivores is poorly characterized. In the current study, we focused on a mite-herbivore, specifically, the two-spotted spider mite (TSSM), which is one of the major agricultural pests worldwide. Our results showed that TSSM-induced leaf damage (visualized by trypan blue staining) and oviposition rate (measured as daily female fecundity) decreased after EL pre-treatment in wild-type Arabidopsis plants, but the observed responses were not wavelength specific...
October 2017: Experimental & Applied Acarology
Emilie Courrier, Didier Renault, Mathilde Kaspi, Agathe Marcon, Victor Lambert, Thibaud Garcin, Frederic Chiambaretta, Gerhard Garhofer, Gilles Thuret, Philippe Gain
PURPOSE: To describe and validate the micro-instillation of fluorescein on the ocular surface by a disposable calibrated inoculation loop to improve corneal and conjunctival staining quality. METHODS: Accuracy and precision of the volume of 0.5% sodium fluorescein collected by a single use 1 μl-calibrated inoculation loop were measured using a precision balance. Twenty patients (40 eyes) suffering from dry eye syndrome were enrolled in a prospective interventional nonrandomized study...
October 25, 2017: Acta Ophthalmologica
Tinghong Tan, Yanni Sun, Shishuai Luo, Chao Zhang, Huapeng Zhou, Honghui Lin
Boea hygrometrica (B. hygrometrica) can tolerate severe desiccation and resume photosynthetic activity rapidly upon water availability. However, little is known about the mechanisms by which B. hygrometrica adapts to dehydration and resumes competence upon rehydration. Here we determine how B. hygrometrica deals with oxidative stress, excessive excitation/electron pressures as well as photosynthetic apparatus modulation during dehydration/rehydration. By measuring ROS generation and scavenging efficiency, we found that B...
November 1, 2017: Plant & Cell Physiology
Klaus H Eckstein, Holger Hartleb, Melanie M Achsnich, Friedrich Schöppler, Tobias Hertel
Doping by chemical or physical means is key for the development of future semiconductor technologies. Ideally, charge carriers should be able to move freely in a homogeneous environment. Here, we report on evidence suggesting that excess carriers in electrochemically p-doped semiconducting single-wall carbon nanotubes (s-SWNTs) become localized, most likely due to poorly screened Coulomb interactions with counterions in the Helmholtz layer. A quantitative analysis of blue-shift, broadening, and asymmetry of the first exciton absorption band also reveals that doping leads to hard segmentation of s-SWNTs with intrinsic undoped segments being separated by randomly distributed charge puddles approximately 4 nm in width...
October 24, 2017: ACS Nano
Weiqi Fu, Amphun Chaiboonchoe, Basel Khraiwesh, Mehar Sultana, Ashish Jaiswal, Kenan Jijakli, David R Nelson, Ala'a Al-Hrout, Badriya Baig, Amr Amin, Kourosh Salehi-Ashtiani
Diatoms, considered as one of the most diverse and largest groups of algae, can provide the means to reach a sustainable production of petrochemical substitutes and bioactive compounds. However, a prerequisite to achieving this goal is to increase the solar-to-biomass conversion efficiency of photosynthesis, which generally remains less than 5% for most photosynthetic organisms. We have developed and implemented a rapid and effective approach, herein referred to as intracellular spectral recompositioning (ISR) of light, which, through absorption of excess blue light and its intracellular emission in the green spectral band, can improve light utilization...
September 2017: Science Advances
Xin Liu, Bowen Chen, Bingtian Tu, Hao Wang, Weimin Wang, Zhengyi Fu
Transparent MgAlON:Ce fluorescent ceramics with doping content of 0.005, 0.01, and 0.02 at % were fabricated by pressureless sintering. All the samples were dense and large in grain size. Under the excitation of 320 nm UV, the samples emitted blue lights centered around 410 nm. The 0.005 and 0.01 at % Ce(3+) doped samples were single phase by XRD detection, and possessed good optical and mechanical properties, and luminous thermal stability. The fluorescence lifetime, the CL and PL spectra analysis, indicated that most of the luminous centers were segregated in GB, and there was still a small part of second phase existing in 0...
July 13, 2017: Materials
Beatriz Rodríguez-Morilla, Juan A Madrid, Enrique Molina, Angel Correa
Vigilance usually deteriorates over prolonged driving at non-optimal times of day. Exposure to blue-enriched light has shown to enhance arousal, leading to behavioral benefits in some cognitive tasks. However, the cognitive effects of long-wavelength light have been less studied and its effects on driving performance remained to be addressed. We tested the effects of a blue-enriched white light (BWL) and a long-wavelength orange light (OL) vs. a control condition of dim light on subjective, physiological and behavioral measures at 21:45 h...
2017: Frontiers in Psychology
James M Stringham, Nicole T Stringham, Kevin J O'Brien
The dramatic rise in the use of smartphones, tablets, and laptop computers over the past decade has raised concerns about potentially deleterious health effects of increased "screen time" (ST) and associated short-wavelength (blue) light exposure. We determined baseline associations and effects of 6 months' supplementation with the macular carotenoids (MC) lutein, zeaxanthin, and mesozeaxanthin on the blue-absorbing macular pigment (MP) and measures of sleep quality, visual performance, and physical indicators of excessive ST...
June 29, 2017: Foods (Basel, Switzerland)
Megumi Hatori, Claude Gronfier, Russell N Van Gelder, Paul S Bernstein, Josep Carreras, Satchidananda Panda, Frederick Marks, David Sliney, Charles E Hunt, Tsuyoshi Hirota, Toshiharu Furukawa, Kazuo Tsubota
Mammals receive light information through the eyes, which perform two major functions: image forming vision to see objects and non-image forming adaptation of physiology and behavior to light. Cone and rod photoreceptors form images and send the information via retinal ganglion cells to the brain for image reconstruction. In contrast, nonimage-forming photoresponses vary widely from adjustment of pupil diameter to adaptation of the circadian clock. nonimage-forming responses are mediated by retinal ganglion cells expressing the photopigment melanopsin...
2017: NPJ Aging and Mechanisms of Disease
Sepalika Bandara, Zhong Ren, Lu Lu, Xiaoli Zeng, Heewhan Shin, Kai-Hong Zhao, Xiaojing Yang
Photoprotection is essential for efficient photosynthesis. Cyanobacteria have evolved a unique photoprotective mechanism mediated by a water-soluble carotenoid-based photoreceptor known as orange carotenoid protein (OCP). OCP undergoes large conformational changes in response to intense blue light, and the photoactivated OCP facilitates dissipation of excess energy via direct interaction with allophycocyanins at the phycobilisome core. However, the structural events leading up to the OCP photoactivation remain elusive at the molecular level...
June 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yvan Touitou, David Touitou, Alain Reinberg
Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock...
May 12, 2017: Journal of Physiology, Paris
Guillaume Allorent, Dimitris Petroutsos
In photosynthetic organisms, proteins in the light-harvesting complex (LHC) harvest light energy to fuel photosynthesis, whereas photoreceptor proteins are activated by the different wavelengths of the light spectrum to regulate cellular functions. Under conditions of excess light, blue-light photoreceptors activate chloroplast avoidance movements in sessile plants, and blue- and green-light photoreceptors cause motile algae to swim away from intense light. Simultaneously, LHCs switch from light-harvesting mode to energy-dissipation mode, which was thought to be independent of photoreceptor-signaling up until recently...
May 1, 2017: Current Opinion in Plant Biology
Massimiliano Tattini, Federico Sebastiani, Cecilia Brunetti, Alessio Fini, Sara Torre, Antonella Gori, Mauro Centritto, Francesco Ferrini, Marco Landi, Lucia Guidi
Photosynthetic performance and the expression of genes involved in light signaling and the biosynthesis of isoprenoids and phenylpropanoids were analysed in green ('Tigullio', TIG) and red ('Red Rubin', RR) basil. The aim was to detect the physiological and molecular response mechanisms to high sunlight. The attenuation of blue-green light by epidermal anthocyanins was shown to evoke shade-avoidance responses with consequential effects on leaf morpho-anatomical traits and gas exchange performance. Red basil had a lower mesophyll conductance, partially compensated by the less effective control of stomatal movements, in comparison with TIG...
April 1, 2017: Journal of Experimental Botany
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"