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Photo sensitivity

David Akerele, Dragan Ljolje, Eldin Talundzic, Venkatachalam Udhayakumar, Naomi W Lucchi
Accurate diagnosis of malaria infections continues to be challenging and elusive, especially in the detection of submicroscopic infections. Developing new malaria diagnostic tools that are sensitive enough to detect low-level infections, user friendly, cost effective and capable of performing large scale diagnosis, remains critical. We have designed novel self-quenching photo-induced electron transfer (PET) fluorogenic primers for the detection of P. ovale by real-time PCR. In our study, a total of 173 clinical samples, consisting of different malaria species, were utilized to test this novel PET-PCR primer...
2017: PloS One
Saniyya Khan, Imrana Naseem
The accompanied tissue devastation and systemic toxicity of chemotherapy has shifted the quest for having an effective and palliative cancer therapy towards photodynamic therapy (PDT). Riboflavin (Rf), an essential micronutrient is emerging as a potent tool of PDT, due to its excellent photosensitizing properties. It can be used as an efficient adjuvant for various anticancer drugs. The hemolytic and proteolytic effect of photoilluminated aminophylline (Am), a xanthine derivative, and Rf is well documented in literature...
June 21, 2017: IUBMB Life
Chang Heon Lee, Jeff Folz, Wuliang Zhang, Janggun Jo, Joel W Y Tan, Xueding Wang, Raoul Kopelman
Ion-selective optodes (ISOs), the optical analog of ion-selective electrodes, have played an increasingly important role in chemical and biochemical analysis. Here we extend this technique to ion-selective photo-acoustic optodes (ISPAOs) that serve at the same time as fluorescence-based ISOs, and apply it specifically to potassium (K+). Notably, the potassium ion is one of the most abundant cations in biological systems, involved in numerous physiological and pathological processes. Furthermore, it has been recently reported that the presence of abnormal extracellular potassium concentrations in tumors suppresses the immune responses and thus suppresses immunotherapy...
June 21, 2017: Analytical Chemistry
Fakir M Amirul Islam
BACKGROUND: To evaluate the accuracy and reliability of fundus retinal photos graded by local graders in Bangladesh with those graded by an expert at the Centre for Eye Research Australia (CERA) in the context of mass scale diabetic retinopathy (DR) screening in Bangladesh. METHODS: A population-based cross-sectional study of 3,104 adults identified 213 (7.2%) eligible patients with diabetes of age ≥ 40 years in 2012-2013. Retinal photographs were collected using a non-mydriatic digital fundus retinal camera and a two-field imaging protocol...
2017: PloS One
Ping Li, Mareike Müller, Matthew Wook Chang, Martin Frettlöh, Holger Schönherr
Quorum sensing, in which bacteria communities use signaling molecules for inter- and intracellular communication, has been intensively studied in recent decades. In order to fabricate highly sensitive easy-to-handle point of care biosensors that detect quorum sensing molecules, we have developed, as is reported here, reporter bacteria entrapped alginate-methacrylate (alginate-MA) hydrogel beads. The alginate-MA beads, which were obtained by electrostatic extrusion, were reinforced by photo-crosslinking to increase stability and thereby to reduce bacteria leaching...
June 19, 2017: ACS Applied Materials & Interfaces
Daniel Nohr, Bernd Paulus, Ryan Rodriguez, Asako Okafuji, Robert Bittl, Erik Schleicher, Stefan Weber
Light-generated short-lived radial pairs have been suggested to play pivotal roles in cryptochromes and photolyases. Chryptochromes are very probably involved in magnetic compass sensing in migratory birds and the magnetic-field-dependent behavior of insects. We examined photo-generated transient states in the cryptochrome of Drosophila melanogaster and in the structurally related DNA-repair enzyme Escherichia coli DNA photolyase. Using pulsed EPR spectroscopy, the exchange and dipolar contributions to the electron spin-spin interaction were determined in a straightforward and direct way...
June 19, 2017: Angewandte Chemie
Manuel Graf, Gerson Mette, Dominik Leuenberger, Yeliz Gurdal, Marcella Iannuzzi, Wolf-Dietrich Zabka, Stephan Schnidrig, Benjamin Probst, Jürg Hutter, Roger Alberto, Jürg Osterwalder
Metal complexes of the tetradentate bipyridine based macrocycle pyrphyrin (Pyr) have recently shown promise as water reduction catalysts in homogeneous photochemical water splitting reactions. In this study, the adsorption and metalation of pyrphyrin on stoichiometric TiO2(110) is investigated in ultrahigh vacuum by means of scanning tunneling microscopy, photoelectron spectroscopy, low-energy electron diffraction, and density functional theory. In a joint experimental and computational effort, the local adsorption geometry at low coverage, the long-range molecular ordering at higher coverage and the electronic structure have been determined for both the bare ligand and the cobalt-metalated Pyr molecule on TiO2...
June 15, 2017: Nanoscale
Xiu Yuan, Peter S Nico, Xiang Huang, Tongxu Liu, Craig Ulrich, Kenneth H Williams, James A Davis
The commonly held assumption that photo-dependent processes dominate H2O2 production in natural waters has been recently questioned. Here, we present evidence for the unrecognized and light-independent generation of H2O2 in groundwater of an alluvial aquifer adjacent to the Colorado River near Rifle, CO. In situ detection using a sensitive chemiluminescent method suggests H2O2 concentrations ranging from lower than the detection limit (< 1 nM) to 54 nM along the vertical profiles obtained at various locations across the aquifer...
June 14, 2017: Environmental Science & Technology
Zhijie Zhang, Hui Liu, Jiayue Xu, Na Zhang
In order to utilize solar light more efficiently, a Bi2WO6 photocatalyst was sensitized by Cu(ii) meso-tetra (4-carboxyphenyl) porphyrin (CuTCPP). The obtained CuTCPP/Bi2WO6 composite exhibited enhanced photocatalytic activity in the degradation of an organic pollutant, rhodamine B (RhB), under simulated solar light irradiation as well as visible light beyond the absorption edge of Bi2WO6 (λ > 450 nm). The enhancement of the photocatalytic activity can be attributed to the sensitization effect of CuTCPP, which increased the visible-light harvesting, as well as the well-matched overlapping band structures between CuTCPP and Bi2WO6, which facilitated the separation of photo-generated electron-hole pairs...
June 14, 2017: Photochemical & Photobiological Sciences
Palraj Ranganathan, Ragu Sasikumar, Shen-Ming Chen, Syang-Peng Rwei, Pedaballi Sireesha
We applied the nitrogen-doped graphene@nickel oxide (NGE/NiO) nanocomposite doped TiO2 as a photo-anode for dye-sensitized solar cells (DSSCs) on fluorine-doped tin oxide (FTO) substrates by screen printing method. Power conversion efficiency (PCE) of 9.75% was achieved for this DSSCs device, which is greater than that of DSSCs devices using GO/TiO2, and NiO/TiO2 based photo-anodes (PCE=8.55, and 9.11%). Also, the fill factor (FF) of the DSSCs devices using the NGE/NiO/TiO2 nanocomposite photo-anode was better than that of other photo-anodes...
June 10, 2017: Journal of Colloid and Interface Science
Dawei Fan, Haoyuan Wang, Malik Saddam Khan, Chunzhu Bao, Huan Wang, Dan Wu, Qin Wei, Bin Du
A novel ultrasensitive label-free immunosensor based on BiOBr/Ag2S composite with high visible-light photoelectrochemical activity was prepared for the detection of insulin. After BiOBr was modified by thioglycolic acid, Ag2S nanoparticles were grown in-situ on the surface of BiOBr hierarchical microspheres to first form novel BiOBr/Ag2S composite. When ascorbic acid (AA) was used as an efficient electron donor for scavenging photo-generated holes, BiOBr/Ag2S composite material showed excellent photoelectrochemical activity...
June 10, 2017: Biosensors & Bioelectronics
Xiaoni Fang, Yaokai Duan, Yujie Liu, Gary Adkins, Weijun Zang, Wenwan Zhong, Liang Qiao, Baohong Liu
In light of the significance of cytochrome P450 (CYP) catalyzed drug metabolism for
drug development and toxicity screening, it is very important to in-vitro imitate natural metabolic pathways accurately and efficiently. Herein, a novel and simple photochemical bionanoreactor has been constructed for efficient visible-light-driven in-vitro drug metabolism based on eosin Y functionalized macroporous ordered silica foams (MOSF-EY). Due to the unique transfer of photo-induced electrons from photo-sensitizers to CYP heme domain, CYP catalyzed drug metabolism can be in-vitro driven by the MOSF-EY nanoreactor under the irradiation of visible light...
June 13, 2017: Analytical Chemistry
Pengfei Lv, Yixin Yao, Dawei Li, Huimin Zhou, Muhammad Awais Naeem, Quan Feng, Jieyu Huang, Yibing Cai, Qufu Wei
Nitrogen-doped carbon dots (N-CDs) were synthesized through a facile hydrothermal method using citric acid (CA) and ethanediamine (EDA) as precursors. A green and simple fluorescence biosensor was obtained by biosynthesis of bacterial cellulose (BC)/N-CDs. As-prepared N-CDs with rich functional groups exhibited a blue emission under the excitation wavelength of 350nm. Biosynthesis of BC/N-CDs was analyzed by Digital photos, Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). The results indicated that N-CDs were successfully anchored on BC...
September 15, 2017: Carbohydrate Polymers
Devasier Bennet, Buddolla Viswanath, Sanghyo Kim, Jeong Ho An
The aim of this study was to analyze photo-dynamic and photo-pathology changes of different color light radiations on human adult skin cells. We used a real-time biophysical and biomechanics monitoring system for light-induced cellular changes in an in vitro model to find mechanisms of the initial and continuous degenerative process. Cells were exposed to intermittent, mild and intense (1-180 min) light with On/Off cycles, using blue, green, red and white light. Cellular ultra-structural changes, damages, and ECM impair function were evaluated by up/down-regulation of biophysical, biomechanical and biochemical properties...
May 24, 2017: Oncotarget
Qingqing Qiu, Ping Wang, Lingling Xu, Dejun Wang, Yanhong Lin, Tengfeng Xie
Anatase TiO2 nanowire (NW) films modified with inverted type-I CdS/CdSe core/shell structure QDs have been successfully prepared by the post synthesis ligand-assisted technique. Surface photovoltage (SPV), transient photovoltage (TPV) and transient photocurrent (TPC) measurements demonstrate that CdS/CdSe core/shell structure QD-sensitized TiO2 NWs electrodes favor photoexicited electron injection and charge transfer due to the special photo-electronic features of CdS/CdSe core/shell structure QDs. With a polysulfide electrolyte, the maximum conversion efficiency was 2...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
Jianlu Wang, Hehai Fang, Xudong Wang, Xiaoshuang Chen, Wei Lu, Weida Hu
Two-dimensional (2D) materials have drawn tremendous attention in recent years. Being atomically thin, stacked with van der Waals force and free of surface chemical dangling bonds, 2D materials exhibit several distinct physical properties. To date, 2D materials include graphene, transition metal dichalcogenides (TMDS), black phosphorus, black P(1-x) Asx , boron nitride (BN) and so forth. Owing to their various bandgaps, 2D materials have been utilized for photonics and optoelectronics. Photodetectors based on 2D materials with different structures and detection mechanisms have been established and present excellent performance...
June 8, 2017: Small
Sergey A Shvetsov, Alexander V Emelyanenko, Natalia I Boiko, Jui-Hsiang Liu, Alexei R Khokhlov
Reversible orientational transitions in the droplets of a nematic liquid crystal (NLC) caused by the change of boundary conditions under the low intensity diode illumination are investigated. Photosensitivity of NLC is achieved by the addition of the dendrimer compound with azobenzene terminal groups. Two types of NLC droplets in glycerol are considered: the spherical droplets in the bulk of glycerol and the droplets laid-down onto the solid substrate. In the second case, the first order phase transition is revealed...
June 7, 2017: Journal of Chemical Physics
Anthony Digrado, Aurélie Bachy, Ahsan Mozaffar, Niels Schoon, Filippo Bussotti, Crist Amelynck, Anne-Catherine Dalcq, Marie-Laure Fauconnier, Marc Aubinet, Bernard Heinesch, Patrick du Jardin, Pierre Delaplace
Several experiments have highlighted the complexity of stress interactions involved in plant response. The impact in field conditions of combined environmental constraints on the mechanisms involved in plant photosynthetic response, however, remains understudied. In a long-term field study performed in a managed grassland, we investigated the photosynthetic apparatus response of the perennial ryegrass (Lolium perenne) to environmental constraints and its ability to recover and acclimatize. Frequent field measurements of chlorophyll ɑ fluorescence (ChlF) were made in order to determine the photosynthetic performance response of a population of L...
June 8, 2017: Physiologia Plantarum
M Hendrikx, A P H J Schenning, D J Broer
The light-induced surface topography of a liquid crystal polymer coating is brought into a patterned oscillatory deformation. A dichroic photo-responsive azobenzene is co-aligned with the planar oriented nematic liquid crystal network molecules which makes the surface deformation sensitive to polarized UV light. Locally selective actuation is achieved in coatings with a complex alignment pattern. Dynamic oscillation, as controlled by the actuation and relaxation kinetics of the polymer, is obtained by a continuous change in the polarization of the UV source...
June 21, 2017: Soft Matter
Andrea Capozzi, Tian Cheng, Giovanni Boero, Christophe Roussel, Arnaud Comment
Hyperpolarization via dynamic nuclear polarization (DNP) is pivotal for boosting magnetic resonance imaging (MRI) sensitivity and dissolution DNP can be used to perform in vivo real-time (13)C MRI. The type of applications is however limited by the relatively fast decay time of the hyperpolarized spin state together with the constraint of having to polarize the (13)C spins in a dedicated apparatus nearby but separated from the MRI magnet. We herein demonstrate that by polarizing (13)C with photo-induced radicals, which can be subsequently annihilated using a thermalization process that maintains the sample temperature below its melting point, hyperpolarized (13)C-substrates can be extracted from the DNP apparatus in the solid form, while maintaining the enhanced (13)C polarization...
June 1, 2017: Nature Communications
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