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Artificial lighting

Indrajit Shown, Satyanarayana Samireddi, Yu-Chung Chang, Raghunath Putikam, Po-Han Chang, Amr Sabbah, Fang-Yu Fu, Wei-Fu Chen, Chih-I Wu, Tsyr-Yan Yu, Po-Wen Chung, M C Lin, Li-Chyong Chen, Kuei-Hsien Chen
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS2 (SnS2-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photophysical properties as compared with undoped SnS2...
January 12, 2018: Nature Communications
Zhe Chen, Zhen Zhang, Yang Bu, Fengzhao Dai, Tanghuai Fan, Huibin Wang
Underwater optical environments are seriously affected by various optical inputs, such as artificial light, sky light, and ambient scattered light. The latter two can block underwater object segmentation tasks, since they inhibit the emergence of objects of interest and distort image information, while artificial light can contribute to segmentation. Artificial light often focuses on the object of interest, and, therefore, we can initially identify the region of target objects if the collimation of artificial light is recognized...
January 12, 2018: Sensors
Martin Ludvigsen, Jørgen Berge, Maxime Geoffroy, Jonathan H Cohen, Pedro R De La Torre, Stein M Nornes, Hanumant Singh, Asgeir J Sørensen, Malin Daase, Geir Johnsen
Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels...
January 2018: Science Advances
Loren Yavelberg, Dessi Zaharieva, Ali Cinar, Michael C Riddell, Veronica Jamnik
BACKGROUND: The increasing popularity of wearable technology necessitates the evaluation of their accuracy to differentiate physical activity (PA) intensities. These devices may play an integral role in customizing PA interventions for primary prevention and secondary management of chronic diseases. For example, in persons with type 1 diabetes (T1D), PA greatly affects glucose concentrations depending on the intensity, mode (ie, aerobic, anaerobic, mixed), and duration. This variability in glucose responses underscores the importance of implementing dependable wearable technology in emerging avenues such as artificial pancreas systems...
January 1, 2018: Journal of Diabetes Science and Technology
Markus Antonietti, Alexandr Savateev
Water splitting to its elements, either by electrochemistry or by solar light, is among the most covered areas in nanostructured functional materials. This personal account article analyzes potential downstream translation problems and reviews alternative chemistries with a potential higher return. Liberation of oxygen for accepting the holes is a kinetically demanding half reaction afflicted with kinetic hindrances and high overpotentials, while at the same time no marketable value is created (atmospheric oxygen is free to use)...
January 10, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Shin-Ichi Naya, Takahiro Kume, Ryo Akashi, Musashi Fujishima, Hiroaki Tada
A key material for artificial photosynthesis including water splitting is heteronanostructured (HNS) photocatalysts. The photocatalytic activity depends on the geometry and dimension, and the quality of junctions between the components. Here we present a half-cut Au(core)-CdS(shell) (HC-Au@CdS) nanoegg as a new HNS plasmonic photocatalyst for water splitting. UV-light irradiation of Au nanoparticle (NP)-loaded ZnO (Au/ZnO) at 50oC induces the selective deposition of hexagonal CdS on the Au surface of Au/ZnO with an epitaxial (EPI) relation of CdS{0001}/Au{111}...
January 10, 2018: Journal of the American Chemical Society
H A Solano-Lamphar, M Kocifaj
The increase of artificial light at night has a terrible impact on organisms with nightlife patterns such as a migration, nutrition, reproduction and collective interaction. Plants are not free from this issue as they have life cycle events occurring not only yearly but also daily. Such events relate to daytime variations with seasons in which the flowers of deciduous trees bloom and the leaves of certain trees fall off and change color. A response of plants to artificial light at night still remains poorly quantified; but recent scientific research suggest that skyglow can disturb plants processes...
January 6, 2018: Journal of Environmental Management
Dennis K P Ng, Xiao-Fei Chen, Mohamed El-Khouly, Kei Ohkubo, Shunichi Fukuzumi
A series of light-harvesting conjugates based on a zinc(II) phthalocyanine core with either two or four boron dipyrromethene (BODIPY) or porphyrin units have been synthesized and characterized. The conjugation of BODIPY/porphyrin units can extend the absorptions of the phthalocyanine core to cover most of the visible region. Upon addition of an imidazole-substituted C60 (C60Im), it can axially bind to the zinc(II) center of the phthalocyanine core via metal-ligand interactions. The resulting complexes form photosynthetic antenna-reaction center mimics in which the BODIPY/porphyrin units serve as the antennas to capture the light and transfer the energy to the phthalocyanine core via efficient excitation energy transfer...
January 6, 2018: Chemistry: a European Journal
Di M Wu, Michelle L Solomon, Gururaj V Naik, Aitzol García-Etxarri, Mark Lawrence, Alberto Salleo, Jennifer A Dionne
Chameleons are masters of light, expertly changing their color, pattern, and reflectivity in response to their environment. Engineered materials that share this tunability can be transformative, enabling active camouflage, tunable holograms, and novel colorimetric medical sensors. While progress has been made in creating artificial chameleon skin, existing schemes often require external power, are not continuously tunable, and may prove too stiff or bulky for applications. Here, a chemically tunable, large-area metamaterial is demonstrated that accesses a wide range of colors and refractive indices...
January 8, 2018: Advanced Materials
Shuai Chen, Zheng Lou, Di Chen, Guozhen Shen
For the mimicry of human visual memory, a prominent challenge is how to detect and store the image information by electronic devices, which demands a multifunctional integration to sense light like eyes and to memorize image information like the brain by transforming optical signals to electrical signals that can be recognized by electronic devices. Although current image sensors can perceive simple images in real time, the image information fades away when the external image stimuli are removed. The deficiency between the state-of-the-art image sensors and visual memory system inspires the logical integration of image sensors and memory devices to realize the sensing and memory process toward light information for the bionic design of human visual memory...
January 8, 2018: Advanced Materials
S Jimena Mora, Emmanuel Odella, Gary F Moore, Devens Gust, Thomas A Moore, Ana L Moore
Artificial photosynthetic constructs can in principle operate more efficiently than natural photosynthesis because they can be rationally designed to optimize solar energy conversion for meeting human demands rather than the multiple needs of an organism competing for growth and reproduction in a complex ecosystem. The artificial photosynthetic constructs described in this Account consist primarily of covalently linked synthetic chromophores, electron donors and acceptors, and proton donors and acceptors that carry out the light absorption, electron transfer, and proton-coupled electron transfer (PCET) processes characteristic of photosynthetic cells...
January 8, 2018: Accounts of Chemical Research
Tatiana Moura Branco, Nádia Castanho Valério, Vânia Isabel Rodrigues Jesus, Cristina Jesus Dias, Maria G P M S Neves, Maria A F Faustino, Adelaide Almeida
In this study, the effect of antimicrobial photodynamic therapy (aPDT) and aPDT combined with antibiotics to inactivate Staphylococcus aureus in vitro and ex vivo was compared. The tetracationic porphyrin 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (Tetra-Py+-Me) was used to inactivate S. aureus in phosphate buffer solution (PBS) (in vitro) and in pork skin artificially contaminated with S. aureus (ex vivo). The results showed an efficient reduction of 8 log in PBS, after 180 min of irradiation under white light at 4...
January 4, 2018: Photodiagnosis and Photodynamic Therapy
Ruirui Li, Xin Sui, Chao Li, Jiaqiao Jiang, Jin Zhai, Longcheng Gao
Gas messenger molecule Nitric Oxide (NO) plays important roles in K+ nanochannels of guard cells by binding directly to the heme-containing enzymes. Inspired by this natural phenomenon, we developed artificial K+ nanochannels modified with ferroporphyrin, where NO triggered the nanochannels turn to be "ON" states from the ferroporphyrin blocked "OFF" states. The mechanism relies on the fact that NO has higher affinity with ferroporphyrin compared to carboxyl groups on the nanochannels surface. The synergistic effect of the released carboxyl groups and the conically asymmetric shape leads the ion transportation to be diode-like...
January 5, 2018: ACS Applied Materials & Interfaces
Peter Augustin, Marina Toplak, Katharina Fuchs, Eva Christine Gerstmann, Ruth Prassl, Andreas Winkler, Peter Macheroux
The heterodimeric human electron transferring flavoprotein (hETF) transfers electrons from at least thirteen different flavin dehydrogenases to the mitochondrial respiratory chain through a non-covalently bound FAD cofactor. Here, we describe the discovery of an irreversible and pH-dependent oxidation of the 8α-methyl group to 8-formyl-FAD (8f-FAD), which represents a unique chemical modification of a flavin cofactor in the human flavoproteome. Furthermore, a set of hETF variants revealed that several conserved amino acid residues in the FAD binding pocket of electron transferring flavoproteins are required for the conversion to the formyl group...
January 4, 2018: Journal of Biological Chemistry
Gong Cheng, Xiaohui Han, Si-Jie Hao, Merisa Nisic, Si-Yang Zheng
Remote and noninvasive modulation of protein activity is essential for applications in biotechnology and medicine. Optical control has emerged as the most attractive approach owing to its high spatial and temporal resolutions; however, it is challenging to engineer light responsive proteins. In this work, a near-infrared (NIR) light-responsive graphene-silica-trypsin (GST) nanoreactor is developed for modulating the bioactivity of trypsin molecules. Biomolecules are spatially confined and protected in the rationally designed compartment architecture, which not only reduces the possible interference but also boosts the bioreaction efficiency...
January 4, 2018: ACS Applied Materials & Interfaces
Dae Ho Jung, Joon Woo Lee, Woo Hyun Kang, In Ha Hwang, Jung Eek Son
Photosynthesis is an important physiological response for determination of CO₂ fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango (Mangifera indica L...
January 4, 2018: International Journal of Molecular Sciences
Chih-Hsiang Huang, Yu-Wen Chen, Chih-Ming Chen
Titanium (Ti) has high potential in many practical applications such as biomedicine, architecture, aviation, and energy. In this study, we demonstrate an innovative application of dye-sensitized solar cell (DSSC) based on Ti photoanode that can be integrated into the roof engineering of large-scale architectures. A chromatic Ti foil produced by anodizing oxidation (coloring) technology (AOT) is an attractive roof material for large-scale architecture, showing a colorful appearance due to the formation of a reflective TiO2 thin layer on both surfaces of Ti...
January 4, 2018: ACS Applied Materials & Interfaces
Jamie Craggs, James R Guest, Michelle Davis, Jeremy Simmons, Ehsan Dashti, Michael Sweet
For many corals, the timing of broadcast spawning correlates strongly with a number of environmental signals (seasonal temperature, lunar, and diel cycles). Robust experimental studies examining the role of these putative cues in triggering spawning have been lacking until recently because it has not been possible to predictably induce spawning in fully closed artificial mesocosms. Here, we present a closed system mesocosm aquarium design that utilizes microprocessor technology to accurately replicate environmental conditions, including photoperiod, seasonal insolation, lunar cycles, and seasonal temperature from Singapore and the Great Barrier Reef (GBR), Australia...
December 2017: Ecology and Evolution
Shichen Lian, Mohamad S Kodaimati, Emily A Weiss
This paper describes the use of electrostatic assemblies of negatively charged colloidal CuInS2/ZnS quantum dot (QD) sensitizers and positively charged, trimethylamino-functionalized iron tetraphenylporphyrin catalysts (FeTMA) to photoreduce CO2 to CO in water, upon illumination with 450-nm light. This system achieves a turnover number (TON) of CO (per FeTMA) of 450 after 30 h of illumination, with a selectivity of 99%. Its sensitization efficiency (TON per Joule of photons absorbed) is a factor of eleven larger than the previous record for photosensitization of an iron porphyrin catalyst for this reaction, held by a system in which both QDs and metal porphyrin were uncharged...
January 3, 2018: ACS Nano
Ádám Egri, Dénes Száz, Alexandra Farkas, Ádám Pereszlényi, Gábor Horváth, György Kriska
Numerous negative ecological effects of urban lighting have been identified during the last decades. In spite of the development of lighting technologies, the detrimental effect of this form of light pollution has not declined. Several insect species are affected including the night-swarming mayfly Ephoron virgo: when encountering bridges during their mass swarming, these mayflies often fall victim to artificial lighting. We show a simple method for the conservation of these mayflies exploiting their positive phototaxis...
November 2017: Royal Society Open Science
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