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Photo sensitivity

B A Hussein, J T Huynh, P L Prieto, C P Barran, A E Arnold, O V Sarycheva, A J Lough, B D Koivisto
BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) dyes possess intense absorption profiles that can be exploited in various light harvesting applications. However, redox stability and optimization of frontier molecular orbital energies in these dyes are critical for their successful incorporation into new solar cell materials. This article describes the synthesis and characterization of a family of β-substituted BODIPY-ferrocene dyads with push-pull architectures. Designed to stabilize the photo-oxidized BODIPY for dye-sensitized solar cell (DSSC) applications, some deleterious electron transfer behaviours emerged when the ferrocene unit was conjugated to electron deficient BODIPYs...
March 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yang Jin, Xiaolong An, Mingqiao Ge
In this study, we fabricated a heat-stimulated luminous fiber (HSLF) by wet spinning. The HSLF consists of Sr₂ZnSi₂O₇: Eu2+ , Dy3+ (SZSO), Y₂O₂S: Eu3+ , Mg2+ , Ti4+ (YOS), and heat-sensitive green TF-G pigment (HSGP). SZSO and YOS serve as a source of luminescence to yield a long afterglow system. HSGP is a heat-stimulating agent which develops the link between luminescence and temperature for HSLF. The luminescence of the HSLF is dull below 30 °C, but vivid above 30 °C. The luminescence of HSLFs can be stimulated by low heat (human body temperature)...
March 15, 2018: Materials
Jing Ruan, Ying Wang, Fang Li, Renbing Jia, Guangming Zhou, Chunlin Shao, Liqi Zhu, Malin Cui, Da-Peng Yang, Shengfang Ge
Combination of drug chemotherapy and ray radiation is the main solution for treating patients with advanced colorectal carcinoma, but the toxicity and adverse effects caused in the surrounding normal tissues and the radio resistance in tumor site will severely influence its therapeutic effect. Nano radiosensitizer is an ideal choice for improving the tumor radiotherapy effects thanks to its high degree of tumor tissue uptake and secondary electrons productivity. Graphene quantum dots (GQDs) have good oxidative stress response and significantly high phototoxicity, and are regarded as a potential nano radiosensitizer...
March 15, 2018: ACS Applied Materials & Interfaces
Shuang Yang, Feng Zhang, Jia Tai, Yang Li, Yang Yang, Hui Wang, Jianxu Zhang, Zhigang Xie, Bin Xu, Haizheng Zhong, Kun Liu, Bai Yang
Perovskite quantum dots (PQDs) exhibit remarkable photoluminescence properties; however, their use in biological applications is hindered by their extreme sensitivity to water. We report a facile and general strategy for the preparation of aqueous colloidally stable polystyrene-b-poly(ethyl oxide) (PS-b-PEO) grafted MAPbBr3 QDs (MA = methylammonium): transferring the as-synthesized PQD@PS-b-PEO from toluene into water using precipitation in hexane as a critical intermediate step. When rehydrating the precipitate in water, the PQDs can be dispersed well individually or self-assembled into well-defined vesicular nanostructures with high photoluminescence quantum yields of up to 43%, high color purity (full width at half maximum down to 18 nm), and long average photoluminescence lifetimes up to 164 ns...
March 14, 2018: Nanoscale
Amanpreet Kaur Jassal, Balkaran Singh Sran, Yan Suffren, Kevin Bernot, Fabrice Pointillart, Olivier Cador, Geeta Hundal
Single crystal diffraction studies reveal the formation of the following 10 new complexes of lighter Ln(iii) ions with general formulas {[Ln(μ2 -L1)3 ·(H2 O)2 ]·H2 O}n (Ln = Nd (1) and Eu (2)), [Nd(μ2 -L2)2 ·(CH3 COO)·(H2 O)2 ]n (3), [Ln2 (μ2 -L2)5 ·(L2)·(H2 O)4 ]n (Ln = Sm (4), Ce (5), and Pr (6)), [La2 (μ2 -L2)6 ·(H2 O)3 ·(DMF)]n (7) (DMF = dimethylformamide), [Ln(μ2 -L2)2 ·(L2)·(H2 O)3 ]2 (Ln = Eu (8) and Gd (9)) and [Gd(L2)·(CH3 COO)2 ·(H2 O)2 ]2 (10), where L1 and L2 are anions of 3,5- and 2,4-dinitrobenzoic acid, respectively...
March 14, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
D Li, A Ruotolo
The Hall effect in metals is too small to have practical applications. Instead, the same effect in semiconductors is the standard for magnetic field sensing. Yet, in semiconducting Hall-sensors, Joule heating severely compromises the linearity range. We here show that a Hall effect can be photo-induced in metals used for bias-free magnetic sensing. The system consists of a transparent metal that forms a Schottky contact to a semiconductor. Light reaching the interface results in the injection of charge from the space charge region...
March 12, 2018: Scientific Reports
Aleksandra Skrajna, Xiao-Cui Yang, Michal Dadlez, William F Marzluff, Zbigniew Dominski
3' end cleavage of metazoan replication-dependent histone pre-mRNAs requires the multi-subunit holo-U7 snRNP and the stem-loop binding protein (SLBP). The exact composition of the U7 snRNP and details of SLBP function in processing remain unclear. To identify components of the U7 snRNP in an unbiased manner, we developed a novel approach for purifying processing complexes from Drosophila and mouse nuclear extracts. In this method, catalytically active processing complexes are assembled in vitro on a cleavage-resistant histone pre-mRNA containing biotin and a photo-sensitive linker, and eluted from streptavidin beads by UV irradiation for direct analysis by mass spectrometry...
February 26, 2018: Nucleic Acids Research
Gottfried Martin, David Conrad, Bertan Cakir, Günther Schlunck, Hansjürgen T Agostini
PURPOSE: Retinal vein occlusion (RVO) has been investigated in several laser-induced animal models using pigs, rabbits and rats. However, laser-induced RVO has been rarely reported in mice, despite the impressive number of available mutants, ease of handling and cost effectiveness. The aim of this study was to further assess the feasibility of a RVO mouse model for gene expression analysis and its possible use to investigate effects of hypoxia. METHODS: C57Bl/6J mice were injected with eosin Y for photo-sensitization...
2018: PloS One
Xu Zhen, Chen Xie, Kanyi Pu
Nanoparticles for photothermal therapy: Real-time temperature monitoring is critical to reduce the nonspecific damage during photothermal therapy (PTT); however, PTT agents that can emit temperature-related signals are rare and limited to few inorganic nanoparticles. We herein synthesize a semiconducting polymer nanococktail (SPNCT ) that can not only convert photo-energy to heat but also emit temperature-correlated luminescence after cessation of light excitation. Such an afterglow luminescence of the SPNCT detects tumors more sensitively than fluorescence as a result of the elimination of tissue autofluorescence, while its temperature-dependent nature allows tumor temperature to be optically monitored under near-infrared (NIR) laser irradiation...
March 12, 2018: Angewandte Chemie
Prasad G Mahajan, Nilam C Dige, Netaji K Desai, Shivajirao R Patil, Vijay V Kondalkar, Seong-Karp Hong, Ki Hwan Lee
Nowadays scientist over the world are engaging to put forth improved methods to detect metal ion in an aqueous medium based on fluorescence studies. A simple, selective and sensitive method was proposed for detection of Co2+ ion using fluorescent organic nanoparticles. We synthesized a fluorescent small molecule viz. 4,4'-{benzene-1,4-diylbis-[(Z)methylylidenenitrilo]}dibenzoic acid (BMBA) to explore its suitability as sensor for Co2+ ion and biocompatibility in form of nanoparticles. Fluorescence nanoparticles (BMBANPs) prepared by simple reprecipitation method...
March 3, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Claudia Pelosi, Giuseppe Capobianco, Giorgia Agresti, Giuseppe Bonifazi, Fabio Morresi, Sara Rossi, Ulderico Santamaria, Silvia Serranti
The aim of this work is to investigate the stability to simulated solar radiation of some paintings samples through a new methodological approach adopting non-invasive spectroscopic techniques. In particular, commercial watercolours and iron oxide based pigments were used, these last ones being prepared for the experimental by gum Arabic in order to propose a possible substitute for traditional reintegration materials. Reflectance spectrophotometry in the visible range and Hyperspectral Imaging in the short wave infrared were chosen as non-invasive techniques for evaluation the stability to irradiation of the chosen pigments...
March 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Hua Sheng, Myoung Oh, Wojciech T Osowiecki, Wooyul Kim, A Paul Alivisatos, Heinz Frei
Monitoring of visible light sensitized reduction of CO2 at Cu nanoparticles in aqueous solution by rapid-scan ATR FT-IR spectroscopy on the time scale of seconds allowed structural identification of a one-electron intermediate and demonstrated its kinetic relevancy for the first time. Isotopic labelling (12C: 1632, 1358, 1346 cm-1; 13C: 1588, 1326, 1316 cm-1) revealed a species of carbon dioxide dimer radical anion structure, most likely bound to the catalyst surface through carbon. Intermediacy of Cu-C(=O)OCO2- surface species is in agreement with a recently proposed mechanism for eletrocatalytic CO2 reduction at Cu metal nanoparticles based on Tafel slope analysis...
March 9, 2018: Journal of the American Chemical Society
Zhengli Hu, Zi-Yuan Li, Yi-Lun Ying, Junji Zhang, Chan Cao, Yi-Tao Long, He Tian
Identification of the configuration for the photoresponsive oligonucleotide plays an important role in the ingenious design of DNA nanomolecules and nanodevices. Due to the limited resolution and sensitivity of present methods, it remains a challenge to determine the accurate configuration of photoresponsive oligonucleotides, much less a precise description of their photo-conversion process. Here, we used an aerolysin (AeL) nanopore-based confined space for real-time determination and quantification of the absolute cis/ trans configuration of each azobenzene-modified oligonucleotide (Azo-ODN) with a single molecule resolution...
March 8, 2018: Analytical Chemistry
Bingquan Yang, Lu Li, Kuishan Du, Bingbing Fan, Yue Long, Kai Song
A facile method to realize photo-responsive inverse opal photonic crystal polymer (IOPP) films with an adjustable broad-wavelength-range photonic band gap (PBG) was demonstrated in this communication. When immersing the IOPP film in malachite green carbinol base (MGCB) solution, under light irradiation, the MGCB released hydroxide ions. In this way, optical signals were converted to chemical signals. As a result, the pH sensitive IOPP film expanded and the PBG changed. The band gap movement of the IOPP films with different monomer to cross-linker ratios was studied in this work...
March 8, 2018: Chemical Communications: Chem Comm
Lin Fan, Suk Kyoung Lee, Pai-Yen Chen, Wen Li
An extremely long decay time of hot carriers in graphene at room temperature was observed for the first time by monitoring the photo-induced thermionic emission using a highly-sensitive time-of-flight (TOF) angle-resolved photoemission spectroscopy (ARPES) method. The emission persisted beyond one nanosecond, two orders of magnitude longer than previously reported carrier decay. The long lifetime was attributed to the excitation of image potential states (IPS) at very low laser fluencies.
March 6, 2018: Journal of Physical Chemistry Letters
Ryosuke Ota, Ryoko Yamada, Takahiro Moriya, Tomoyuki Hasegawa
PURPOSE: Cherenkov radiation has recently received attention due to its prompt emission phenomenon, which has the potential to improve the timing performance of radiation detectors dedicated to positron emission tomography (PET). In this study, a Cherenkov based three-dimensional (3D) position sensitive radiation detector was proposed, which is composed of a monolithic lead fluoride (PbF2 ) crystal and a photodetector array of which the signals can be readout independently. METHODS: Monte Carlo simulations were performed to estimate the performance of the proposed detector...
March 6, 2018: Medical Physics
Somayeh M A Mirzaee, Olivier Lebel, Jean-Michel Nunzi
Plasmonic nanostructures can generate energetic "hot" electrons from light in a broadband fashion depending on their shape, size and arrangement. Such structures have a promising use in photodetectors, allowing high speed, broadband, and multicolor photo-detection. Because they function without a bandgap absorption, photon detection at any energy would be possible through engi-neering of the plasmonic nanostructure. Herein, a compact hot electron-based photodetector that combines polarization sensitivity and circularly polarized light detection in the near infrared region was fabricated using an ITO-Au hybrid layer...
March 6, 2018: ACS Applied Materials & Interfaces
Lewis M Antill, Joshua P Beardmore, Jonathan R Woodward
The photochemical reactions of blue-light receptor proteins have received much attention due to their very important biological functions. In addition, there is also growing evidence that the one particular class of such proteins, the cryptochromes, may be associated with not only a biological photo-response but also a magneto-response, which may be responsible for the mechanism by which many animals can respond to the weak geomagnetic field. Therefore, there is an important scientific question over whether it is possible to directly observe such photochemical processes, and indeed the effects of weak magnetic fields thereon, taking place both in purified protein samples in vitro and in actual biochemical cells and tissues...
February 2018: Review of Scientific Instruments
Hasan Norouzi, Karim Khoshgard, Fatemeh Akbarzadeh
Hyperthermia is an anti-cancer treatment in which the temperature of the malignant tumor is increased more than other adjacent normal tissues. Microwave, ultrasound, laser, and radiofrequency sources have been used for hyperthermia of cancerous tissues. In the past decade, near-infrared (NIR) laser for cancer therapy, known as photo-thermal therapy (PTT), was expanded in which the photo-sensitizer agent converts the light photon energy to heat. The heat following PTT can destroy cancer cells. There are some photo-sensitizer agents which have been used for PTT; however, owing to recent advances in nanotechnology, noble metal nanoparticles like gold (Au) nanoparticles (GNPs) have been used successfully in PTT...
February 28, 2018: Lasers in Medical Science
Jasmin S Shaikh, Navajsharif S Shaikh, Sawanta S Mali, Jyoti V Patil, Krishna K Pawar, Pongsakorn Kanjanaboos, Chang Kook Hong, J H Kim, Pramod S Patil
Dye-sensitized solar cells (DSSCs) have aroused great interest and been regarded as a potential renewable energy resource among the third-generation solar cell technologies to fulfill the 21st century global energy demand. DSSCs have notable advantages such as low cost, easy fabrication process and being eco-friendly in nature. The progress of DSSCs over the last 20 years has been nearly constant due to some limitations, like poor long-term stability, narrow absorption spectrum, charge carrier transportation and collection losses and poor charge transfer mechanism for regeneration of dye molecules...
February 28, 2018: Nanoscale
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