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Photo sensitivity

Wenwen Lin, Constantinos C Stoumpos, Oleg Y Kontsevoi, Zhifu Liu, Yihui He, Sanjib Das, Yadong Xu, Kyle M McCall, Bruce W Wessels, Mercouri G Kanatzidis
Cu2I2Se6 is a new wide-bandgap semiconductor with high stability and great potential towards hard radiation and photon detection. Cu2I2Se6 crystallizes in the rhombohedral R3 ̅m space group with a density of d = 5.287 g·cm-3 and a wide bandgap Eg of 1.95 eV. First-principles electronic band structure calculations at the density functional theory level indicate an indirect bandgap and a low electron effective mass me* of 0.32. The congruently melting compound was grown in centimeter-size Cu2I2Se6 single crystals using a vertical Bridgman method...
January 14, 2018: Journal of the American Chemical Society
Qiyang Li, Xiuju Wu, Xiaoli Huang, Yangjun Deng, Nanjian Chen, Dandan Jiang, Lili Zhao, Zhihua Lin, Yonggang Zhao
A hydroxyl functionalized ligand was designed for the construction of MOF materials with aggregation-induced emission (AIE) feature, in which the fluorescence can be deliberately tailored: quenching the fluorescence to an "off" state by the decoration with heterocyclic auxiliary ligand 4,4'-bypyridine (Bpy) in the framework as quenching agent; triggering the enhanced fluorescence to an "on" state by removal of Bpy through the metal competitive coordination substitution strategy. Our study shows that the occurrence of exciton migration between the AIE linker and the conjugated auxiliary ligand Bpy cause the fluorescence quenching...
January 11, 2018: ACS Applied Materials & Interfaces
Miguel Mompeán, Rosa M Sánchez-Donoso, Antonio de la Hoz, Vittorio Saggiomo, Aldrik H Velders, M Victoria Gomez
Among the methods to enhance the sensitivity of nuclear magnetic resonance (NMR) spectroscopy, small-diameter NMR coils (microcoils) are promising tools to tackle the study of mass-limited samples. Alternatively, hyperpolarization schemes based on dynamic nuclear polarization techniques provide strong signal enhancements of the NMR target samples. Here we present a method to effortlessly perform photo-chemically induced dynamic nuclear polarization in microcoil setups to boost NMR signal detection down to sub-picomole detection limits in a 9...
January 9, 2018: Nature Communications
Fangfang Li, Xuan Hu, Fengyi Wang, Baozhan Zheng, Juan Du, Dan Xiao
A simple, rapid, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection was developed by using a FAM (carboxyfluorescein) labeled DNA (FAM-DNA). In this strategy, highly fluorescent FAM-DNA was used as a probe, and nanoceria (CeO2 NPs) acted as an efficient quencher. FAM-DNA attached to the surface of nanoceria through the coordination between the phosphate group of DNA and NP surface, which induced complete quenching in the FAM-DNA fluorescence due to a photo induced electron transfer (PET) process...
March 1, 2018: Talanta
John Axelsson, Tina Sundelin, Mats J Olsson, Kimmo Sorjonen, Charlotte Axelsson, Julie Lasselin, Mats Lekander
Detection and avoidance of sick individuals have been proposed as essential components in a behavioural defence against disease, limiting the risk of contamination. However, almost no knowledge exists on whether humans can detect sick individuals, and if so by what cues. Here, we demonstrate that untrained people can identify sick individuals above chance level by looking at facial photos taken 2 h after injection with a bacterial stimulus inducing an immune response (2.0 ng kg-1 lipopolysaccharide) or placebo, the global sensitivity index being d' = 0...
January 10, 2018: Proceedings. Biological Sciences
Yi Zeng, Xin Du, Bingbing Gao, Bing Liu, Zhuoying Xie, Zhongze Gu
The combination of surface-enhanced Raman scattering (SERS) with high-throughput screening (HTS) has significant importance for highly sensitive and massive workload assays. Although fabrication of HTS-SERS substrates can be achieved by several methods, the high cost as well as large-equipment-dependence limit their applications. Here we report a simple method to fabricate HTS-SERS substrates within one-step process. The HTS-SERS substrate is fabricated by simply UV irradiating a fluoroalkylsilane-modified liquid-repellent TiO2 surface in AgNO3 solution through a photomask...
January 3, 2018: ACS Applied Materials & Interfaces
D Sinha, D De, A Ayaz
Environmental friendly natural dye curcumin extracted from low-cost Curcumina longa stem is used as a photo-sensitizer for the fabrication of ZnO-based dye-sensitized solar cells (DSSC). Nanostructured ZnO is fabricated on a transparent conducting glass (TCO), using a cost-effective chemical bath deposition technique. Scanning electron microscopic images show hexagonal patterned ZnO nano-towers decorated with several nanosteps. The average length of ZnO nano-tower is 5μm and diameter is 1.2μm. The UV-Vis spectroscopic study of the curcumin dye is used to understand the light absorption behavior as well as band gap energy of the extracted natural dye...
December 26, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Veronique Larosa, Andrea Meneghesso, Nicoletta La Rocca, Janina Steinbeck, Michael Hippler, Ildiko Szabo, Tomas Morosinotto
Photosynthetic organisms use sunlight as the primary source of energy to support their metabolism. In eukaryotes reactions responsible of the conversion of light into chemical energy occur in specific organelles, the chloroplasts. In this study we showed that mitochondria also have a seminal influence on cells' energy metabolism and on photosynthetic reactions. This is illustrated by the observation that the strong photosensitivity of Chlamydomonas reinhardtii cells depleted of the chloroplast protein PGRL1 was rescued by the introduction of a mitochondrial mutation affecting respiratory complex I...
December 28, 2017: Plant Physiology
Swapan Pramanick, Jihoon Kim, Jinhwan Kim, Gurusamy Saravanakumar, Dongsik Park, Won Jong Kim
Herein, we report the proof of concept of photo-responsive chemotherapeutics comprising nitric oxide-releasing platinum prodrugs and polymeric micelles. Photo-activatable nitric oxide-releasing donors were integrated into the axial positions of a platinum (IV) prodrug, and the photo-labile hydrophobic groups were grafted in the block copolymers. The hydrophobic interaction between nitric oxide donors and the photo-labile groups allowed for the loading of platinum drugs and nitric oxide-releasing donors in the photo-labile polymeric micelles...
December 27, 2017: Bioconjugate Chemistry
Meriem El Founi, Soliman Mehawed Abdellatif Soliman, Régis Vanderesse, Samir Acherar, Emmanuel Guedon, Isabelle Chevalot, Jérôme Babin, Jean-Luc Six
HYPOTHESIS: For some years, smart nano-objects are one of the main focuses of current research. In the framework of polymeric nanomedicine, o-nitrobenzyl alcohol derivatives lead to light-responsive polymeric materials. At this day, nanomedicine based on polysaccharide/poly(o-nitrobenzyl acrylate) (PNBA) copolymers have never been reported. EXPERIMENTS: For the first time, PNBA core/dextran shell nanoparticles (NPs) were formulated by evaluating two different processes: (i) nanoprecipitation of preformed Dextran-g-PNBA glycopolymers, (ii) emulsion/evaporation using azido-functionalized PNBA and alkynated dextran, carrying out (or not) an interfacial click chemistry reaction...
December 14, 2017: Journal of Colloid and Interface Science
Yusuke Okuno, Silvia Cavagnero
Given its short hyperpolarization time (∼10-6 s) and mostly non-perturbative nature, photo-chemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful tool for sensitivity enhancement in nuclear magnetic resonance. In this study, we explore the extent of 1H-detected 13C nuclear hyperpolarization that can be gained via photo-CIDNP in the presence of small-molecule additives containing a heavy atom. The underlying rationale for this methodology is the well-known external-heavy-atom (EHA) effect, which leads to significant enhancements in the intersystem-crossing rate of selected photosensitizer dyes from photoexcited singlet to triplet...
December 5, 2017: Journal of Magnetic Resonance
Yuting Chen, Linjie Lu, Shixin Ye
Nature has invented photoreceptor proteins that are involved in sensing and response to light in living organisms. Genetic code expansion (GCE) technology has provided new tools to transform light insensitive proteins into novel photoreceptor proteins. It is achieved by the site-specific incorporation of unnatural amino acids (Uaas) that carry light sensitive moieties serving as "pigments" that react to light via photo-decaging, cross-linking, or isomerization. Over the last two decades, various proteins including ion channels, GPCRs, transporters, and kinases have been successfully rendered light responsive owing to the functionalities of Uaas...
December 2017: Yale Journal of Biology and Medicine
Kango Ishimoto, Tomoyuki Tajima, Hideaki Miyake, Masahiro Yamagami, Wataru Kurashige, Yuichi Negishi, Yutaka Takaguchi
To observe a clear-cut example of the formation of mobile carriers from excitons on semiconducting single-walled carbon nanotubes (s-SWCNTs) surrounded by a medium with a high dielectric constant, water-dispersible s-SWCNT nanocomposites were fabricated by physical modifications using poly(amidoamine) dendrimers that contain an aliphatic core. The evolution of H2 from water using these s-SWCNT/dendrimer nanocomposites as photosensitizers under irradiation with visible light demonstrated a photo-induced electron transfer from the s-SWCNTs to the co-catalysts...
December 18, 2017: Chemical Communications: Chem Comm
Ottavia Bettucci, Valeria Saavedra Becerril, T M W J Bandara, Maurizio Furlani, Maria Abrahamsson, Bengt-Erik Mellander, Lorenzo Zani
The electrolyte used in dye-sensitized solar cells (DSSCs) plays a key role in the process of current generation, and hence the analysis of charge-transfer mechanisms both in its bulk and at its interfaces with other materials is of fundamental importance. Because of solvent confinement, gel polymer electrolytes are more practical and convenient to use with respect to liquid electrolytes, but in-depth studies are still necessary to optimize their performances. In this work, gel polymer electrolytes of general formulation polyacrylonitrile (PAN)/ethylene carbonate (EC)/propylene carbonate (PC)/MI, where M+ is a cation in the alkaline series Li-Cs, were prepared and used in DSSCs...
December 18, 2017: Physical Chemistry Chemical Physics: PCCP
Xinnong Wang, Shencheng Fu, Xintong Zhang, Xiuxiu Han, Shuangyan Liu, Lihong Kang, Yang Zhang, Yichun Liu
Noble metal plasmonic resonance has been utilized in optical data storage widely for its excellent photo-transformation efficiency. TiO2 nanoporous films deposited with Ag nanoparticles present outstanding polarization-response and color-modulation ability. However, the low exposure-sensitivity at single wavelength inhibits their application in optical information processing, which is urgent to be improved by innovative methods. Here, we report that Ag nanoparticles were deposited efficiently via continuous laser irradiation in the TiO2 nanoporous film treated by tannic acid, presenting high-efficient monochromic absorption property...
December 11, 2017: Optics Express
Qiusheng Wu, Bingru Huang, Xingyun Peng, Sailing He, Qiuqiang Zhan
Optical super-resolution microscopy has become a powerful technique to help scientists to monitor the sample of interest at nanoscale. Fluorescence emission difference (FED) microscopy, a very facile super-resolution method, does not require high depleting laser intensity and is independent on the species of agents, which makes FED microscopy possess great potential. However, to date, the biomarkers applied in FED microscopy usually suffer from a photo-bleaching problem. In this work, by introducing Er3+ activated upconverting nanoparticles with red-color emission and non-photobleaching properties, we demonstrate nonbleaching super-resolution imaging with FED microscopy...
December 11, 2017: Optics Express
Xin Li, Ying He, Jie Yang, Yin-Hua Jia, Han-Lai Zeng
Abnormal environment weather can cause rice photoperiod-thermo-sensitive genic male sterile (PTGMS) lines fertile or partially fertile and thus cause the mixture of true hybrids with selfing seeds. Seedling-specific green-revertible albino leaf color mutant can be used to distinguish the real hybrids. Besides, it can also be used as an ideal material to research the development of chloroplast and biosynthesis of chlorophyll. The phenotype of leaf color mutants includes light green, yellowing, albino, green-revertible albino...
January 2018: Plant Science: An International Journal of Experimental Plant Biology
Kun-Ruey Shieh, Rong-Jie Chen, Shu-Chuan Yang
The diurnal rhythm is the common event in nature and specially shows in the behavioral patterns. Using the infrared sensor or photo beam detector to detect this 24-h rhythmicity in behaviors of mammalian, including in the rats and mice, is also the common way. The photo-sensory detecting mean is friendly and its advantage is unrestricted by light density and light-dark transition. However, this kind of equipment is cost-expensive and uneasy to fit for home cage in rodents. In this study, we tried to use the video-tracking system to detect the rhythmic activity of rats in their home cages...
December 15, 2017: Chinese Journal of Physiology
Carolin Hartmann, Roshani Patil, Charles P Lin, Mark Niedre
There are many diseases and biological processes that involve circulating cells in the bloodstream, such as cancer metastasis, immunology, reproductive medicine, and stem cell therapies. This has driven significant interest in new technologies for the study of circulating cells in small animal research models and clinically. Most currently used methods require drawing and enriching blood samples from the body, but these suffer from a number of limitations. In contrast, 'in vivo flow cytometry' (IVFC) refers to set of technologies that allow study of cells directly in the bloodstream of the organism in vivo...
December 14, 2017: Physics in Medicine and Biology
Xiao Meng, Junjie Hu, Zhicong Chao, Ying Liu, Huangxian Ju, Quan Cheng
Sample desalting and concentrating is a crucial step prior to MALDI-MS analysis. Current sample pretreatment approaches require tedious fabrication and operation procedures, which are unamenable to high-throughput analysis and also result in sample loss. Here we report the development of a smart MALDI substrate for on-plate desalting, enrichment, and direct MS analysis of protein digests based on thermo-responsive, hydrophilic/hydrophobic transition of surface grafted poly(N-isopropylacrylamide) (PNIPAM) microarrays...
December 14, 2017: ACS Applied Materials & Interfaces
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