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https://www.readbyqxmd.com/read/28239697/optimization-of-highly-sensitive-yag-cr-3-nd-3-nanocrystal-based-luminescent-thermometer-operating-in-an-optical-window-of-biological-tissues
#1
L Marciniak, A Bednarkiewicz, J Drabik, K Trejgis, W Strek
Luminescent and temperature sensitive properties of YAG:Cr(3+),Nd(3+) nanocrystals were analyzed as a function of temperature, nanoparticle size, and excitation wavelength. Due to numerous temperature-dependent phenomena (e.g. Boltzmann population, thermal quenching, and inter-ion energy transfer) occurring in this phosphor, four different thermometer definitions were evaluated with the target to achieve a high sensitivity and broad temperature sensitivity range. Using a Cr(3+) to Nd(3+) emission intensity ratio, the highest 3...
February 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28238373/chemical-and-optical-properties-of-pm2-5-from-on-road-operation-of-light-duty-vehicles-in-delhi-city
#2
Jaiprakash, Gazala Habib
This study reports emission factors of PM2.5, elemental carbon (EC), organic carbon (OC), ions, trace elements and mass absorption cross-sections (MAC) of aerosol emitted from the on-road operation of light duty vehicles of different vintages. A portable dilution system was used to achieve complete quenching of aerosol at near ambient condition. The particles were collected on the filters and analyzed for chemical and light absorbing properties of aerosol. The diesel-powered passenger cars emitted higher PM2...
February 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28238264/the-influence-of-aqueous-inorganic-anions-on-the-reactivity-of-nanoparticles-in-tio2-photocatalysis
#3
Jeffrey Farner Budarz, Andrea Turolla, Aleksander F Piasecki, Jean-Yves Bottero, Manuela Antonelli, Mark R Wiesner
The influence of inorganic anions on the photoreactivity and aggregation of titanium dioxide nanoparticles (NPs) was assessed by dosing carbonate, chloride, nitrate, phosphate and sulfate as potassium salts at multiple concentrations. Nanoparticle stability was monitored in terms of aggregate morphology and electrophoretic mobility (EPM). Aggregates size and fractal dimension were measured over time by laser diffraction, and the isoelectric point (IEP) as a function of anion and concentration was obtained by measuring EPM vs...
February 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28236074/interaction-of-the-signaling-state-analog-and-the-apoprotein-form-of-the-orange-carotenoid-protein-with-the-fluorescence-recovery-protein
#4
Marcus Moldenhauer, Nikolai N Sluchanko, Neslihan N Tavraz, Cornelia Junghans, David Buhrke, Mario Willoweit, Leonardo Chiappisi, Franz-Josef Schmitt, Vladana Vukojević, Evgeny A Shirshin, Vladimir Y Ponomarev, Vladimir Z Paschenko, Michael Gradzielski, Eugene G Maksimov, Thomas Friedrich
Photoprotection in cyanobacteria relies on the interplay between the orange carotenoid protein (OCP) and the fluorescence recovery protein (FRP) in a process termed non-photochemical quenching, NPQ. Illumination with blue-green light converts OCP from the basic orange state (OCP(O)) into the red-shifted, active state (OCP(R)) that quenches phycobilisome (PBs) fluorescence to avoid excessive energy flow to the photosynthetic reaction centers. Upon binding of FRP, OCP(R) is converted to OCP(O) and dissociates from PBs; however, the mode and site of OCP(R)/FRP interactions remain elusive...
February 24, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28235605/studies-of-dna-binding-properties-of-lafutidine-as-adjuvant-anticancer-agent-to-calf-thymus-dna-using-multi-spectroscopic-approaches-nmr-relaxation-data-molecular-docking-and-dynamical-simulation
#5
Hongqin Yang, Peixiao Tang, Bin Tang, Yanmei Huang, Jiawei He, Shanshan Li, Hui Li
The interactions between lafutidine (LAF) and calf thymus DNA (ctDNA) have been investigated both experimentally and theoretically. UV-visible absorption studies confirmed that LAF binds to ctDNA through non-covalent interactions. Fluorescence quenching and time-resolved fluorescence spectroscopy studies showed that the binding of LAF with ctDNA occurred through static quenching mechanism, resulting in the formation of a LAF-ctDNA complex. The binding constants (K) of the complex were found to be around 10(3)M(-1) via NMR relaxation rates and fluorescence data, and the calculated thermodynamic parameters indicated that hydrogen bonds and van der Waals forces played major roles in the binding of LAF to ctDNA...
February 21, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28235382/can-f%C3%A3-rster-theory-describe-stereoselective-energy-transfer-dynamics-in-a-protein-ligand-complex
#6
Silvana Pinheiro, Carles Curutchet
Förster resonance energy transfer (FRET) reactions involving ligands and aromatic amino acids can substantially impact the fluorescence properties of a protein-ligand complex, an impact intimately related to the corresponding binding mode. Structural characterization of such binding events in terms of intermolecular distances can be done through the well-known R-6 distance-dependent Förster rate expression. However, such interpretation suffers from uncertainties underlying Förster theory in the description of the electronic coupling that promotes FRET, mostly related to the dipole-dipole orientation factor, dielectric screening effects and deviations from the ideal dipole approximation...
February 24, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28231085/extraction-identification-and-photo-physical-characterization-of-persimmon-diospyros-kaki-l-carotenoids
#7
Khalil Zaghdoudi, Orleans Ngomo, Régis Vanderesse, Philippe Arnoux, Bauyrzhan Myrzakhmetov, Céline Frochot, Yann Guiavarc'h
Carotenoid pigments were extracted and purified from persimmon fruits using accelerated solvent extraction (ASE). Eleven pigments were isolated and five of them were clearly identified as all-trans-violaxanthine, all-trans-lutein, all-trans-zeaxanthin all-trans-cryptoxanthin and all-trans-β-carotene. Absorption and fluorescence spectra were recorded. To evaluate the potential of ¹O₂ quenching of the purified carotenoids, we used a monocarboxylic porphyrin (P1COOH) as the photosensitizer to produce ¹O₂...
January 12, 2017: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28230538/interrogating-surface-state-of-isolated-and-agglomerated-pbs-quantum-dots-with-solvent-induced-stress
#8
Pin-Hao Sher, Juen-Kai Wang
Applications of quantum dot (QD) are often obstructed by its associated surface electronic states that quench photoluminescence (PL) and hinder charge transport. Their origins are still largely stymied owing to lacking means to regulate their presence. Dispersing PbS QDs in toluene, we show that varying solvent temperature offers an opportunity to modulate their surface electronic state. A comprehensive energy-transfer model explains all anomalous temperature-dependent behaviors of absorption and PL, explicitly revealing PL quenching dynamics of isolated QDs due to induced surface state by imposed solvent stress to their surface ligands...
February 23, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28230157/highly-sensitive-and-adaptable-fluorescence-quenched-pair-discloses-the-substrate-specificity-profiles-in-diverse-protease-families
#9
Marcin Poreba, Aleksandra Szalek, Wioletta Rut, Paulina Kasperkiewicz, Izabela Rutkowska-Wlodarczyk, Scott J Snipas, Yoshifumi Itoh, Dusan Turk, Boris Turk, Christopher M Overall, Leszek Kaczmarek, Guy S Salvesen, Marcin Drag
Internally quenched fluorescent (IQF) peptide substrates originating from FRET (Förster Resonance Energy Transfer) are powerful tool for examining the activity and specificity of proteases, and a variety of donor/acceptor pairs are extensively used to design individual substrates and combinatorial libraries. We developed a highly sensitive and adaptable donor/acceptor pair that can be used to investigate the substrate specificity of cysteine proteases, serine proteases and metalloproteinases. This novel pair comprises 7-amino-4-carbamoylmethylcoumarin (ACC) as the fluorophore and 2,4-dinitrophenyl-lysine (Lys(DNP)) as the quencher...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28229517/affinity-capillary-electrophoresis-and-fluorescence-spectroscopy-for-studying-enantioselective-interactions-between-omeprazole-enantiomer-and-human-serum-albumin
#10
Yujing Xu, Tingting Hong, Xueping Chen, Yibing Ji
Baseline separation of omeprazole (OME) enantiomers was achieved by affinity capillary electrophoresis (ACE), using human serum albumin (HSA) as the chiral selector. The influence of several experimental variables such as HSA concentration, the type and content of organic modifiers, applied voltage and running buffer concentration on the separation was evaluated. The binding of esomeprazole (S-omeprazole, S-OME) and its R-enantiomer (R-omeprazole, R-OME) to HSA under simulated physiological conditions was studied by ACE and fluorescence spectroscopy which was considered as a reference method...
February 23, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28225766/marine-actinobacteria-as-a-source-of-compounds-for-phytopathogen-control-an-integrative-metabolic-profiling-bioactivity-and-taxonomical-approach
#11
Luz A Betancur, Sandra J Naranjo-Gaybor, Diana M Vinchira-Villarraga, Nubia C Moreno-Sarmiento, Luis A Maldonado, Zulma R Suarez-Moreno, Alejandro Acosta-González, Gillermo F Padilla-Gonzalez, Mónica Puyana, Leonardo Castellanos, Freddy A Ramos
Marine bacteria are considered as promising sources for the discovery of novel biologically active compounds. In this study, samples of sediment, invertebrate and algae were collected from the Providencia and Santa Catalina coral reef (Colombian Caribbean Sea) with the aim of isolating Actinobateria-like strain able to produce antimicrobial and quorum quenching compounds against pathogens. Several approaches were used to select actinobacterial isolates, obtaining 203 strains from all samples. According to their 16S rRNA gene sequencing, a total of 24 strains was classified within Actinobacteria represented by three genera: Streptomyces, Micromonospora, and Gordonia...
2017: PloS One
https://www.readbyqxmd.com/read/28225127/high-chloride-content-calcium-silicate-glasses
#12
Xiaojing Chen, Natalia Karpukhina, Delia S Brauer, Robert G Hill
Chloride is known to volatilize from silicate glass melts and until now, only a limited number of studies on oxychloride silicate glasses have been reported. In this paper we have synthesized silicate glasses that retain large amounts of CaCl2. The CaCl2 has been added to the calcium metasilicate composition (CaO·SiO2). Glasses were produced via a melt quench route and an average of 70% of the chloride was retained after melting. Up to 31.6 mol% CaCl2 has been successfully incorporated into these silicate glasses without the occurrence of crystallization...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28225115/solvothermal-assisted-synthesis-of-self-assembling-tio2-nanorods-on-large-graphitic-carbon-nitride-sheets-with-their-anti-recombination-in-the-photocatalytic-removal-of-cr-vi-and-rhodamine-b-under-visible-light-irradiation
#13
Dingze Lu, Pengfei Fang, Wenhui Wu, Junqian Ding, Lulu Jiang, Xiaona Zhao, Chunhe Li, Minchen Yang, Yuanzhi Li, Dahai Wang
TiO2-based nanorods (TNRs) were self-assembled on large graphitic carbon nitride (g-C3N4) sheets via the solvothermal-assisted route. The results demonstrated that the effective anchoring of TNRs (a side length of ca. 200-300 nm) was highly dispersed on the surface of whole g-C3N4 sheets. The shift in the Ti 2p XPS core level spectrum indicated an increase in the net positive charge of the Ti ions, ensuring the formation of an interface between TNRs and g-C3N4. The charge transferred from g-C3N4 sheets to TNRs effectively prevented the recombination of excited charges, which is consistent with the significant quenching of PL...
February 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28225085/aidp-a-novel-n-acyl-homoserine-lactonase-gene-from-antarctic-planococcus-sp
#14
Wah Seng See-Too, Robson Ee, Yan-Lue Lim, Peter Convey, David A Pearce, Wai-Fong Yin, Kok-Gan Chan
Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15(T), isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N-acyl homoserine lactonase, an enzyme that hydrolyzes the ester bond of the homoserine lactone of N-acyl homoserine lactone (AHLs)...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28224784/a-highly-efficient-electrochemiluminescent-ag-nanoclusters-tio2-nanomaterials-as-signal-probe-for-ferrocene-driven-light-switch-bioanalysis
#15
Ying Zhou, Haijun Wang, Ying Zhuo, Yaqin Chai, Ruo Yuan
In this work, a ferrocene (Fc)-driven light switch biosensor for ultrasensitive detection of amyloid-β (Aβ) was designed by utilizing the highly-efficient electrochemiluminescent nanomaterials of Ag NCs/TiO2 nanoflowers (NFs) as signal labels. Through combining the TiO2 NFs as the co-reaction accelerator and dissolved O2 as the intrinsic co-reactant to in suit generate strong oxidizing intermediate radical OH•, the electrochemiluminescence (ECL) of Ag NCs on the TiO2 NFs surface could be significantly promoted in comparion with that of pure Ag NCs in solution...
February 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28223992/carbon-monoxide-is-involved-in-hydrogen-gas-induced-adventitious-root-development-in-cucumber-under-simulated-drought-stress
#16
Yue Chen, Meng Wang, Linli Hu, Weibiao Liao, Mohammed M Dawuda, Chunlan Li
Hydrogen gas (H2) and carbon monoxide (CO) are involved in plant growth and developmental processes and may induce plant tolerance to several stresses. However, the independent roles and interaction effect of H2 and CO in adventitious root development under drought conditions have still not received the needed research attention. We hypothesize that there exists crosstalk between H2 and CO during adventitious root development under drought stress. The results of our current study revealed that 50% (v/v) hydrogen-rich water (HRW), 500 μM Hemin (the CO donor) and 30% (w/v) CO aqueous solution apparently promoted the development of adventitious roots in cucumber explants (Cucumis Sativus L...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28223518/integrated-view-of-internal-friction-in-unfolded-proteins-from-single-molecule-fret-contact-quenching-theory-and-simulations
#17
Andrea Soranno, Andrea Holla, Fabian Dingfelder, Daniel Nettels, Dmitrii E Makarov, Benjamin Schuler
Internal friction is an important contribution to protein dynamics at all stages along the folding reaction. Even in unfolded and intrinsically disordered proteins, internal friction has a large influence, as demonstrated with several experimental techniques and in simulations. However, these methods probe different facets of internal friction and have been applied to disparate molecular systems, raising questions regarding the compatibility of the results. To obtain an integrated view, we apply here the combination of two complementary experimental techniques, simulations, and theory to the same system: unfolded protein L...
February 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28222367/a-novel-turn-on-fluorescent-strategy-for-sensing-ascorbic-acid-using-graphene-quantum-dots-as-fluorescent-probe
#18
Hua Liu, Weidan Na, Ziping Liu, Xueqian Chen, Xingguang Su
In this paper, a facile and rapid fluorescence turn-on assay for fluorescent detection of ascorbic acid (AA) was developed by using the orange emission graphene quantum dots (GQDs). In the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H2O2), catechol can be oxidized by hydroxyl radicals and converted to o-benzoquinone, which can significantly quench the fluorescence of GQDs. However, when AA present in the system, it can consume part of H2O2 and hydroxyl radicals to inhibit the generation of o-benzoquinone, resulting in fluorescence recovery...
February 4, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28221811/deformation-localisation-in-molecular-layers-constrained-between-self-assembled-au-nanoparticles
#19
Guillaume Copie, Moussa Biaye, Heinrich Diesinger, Thierry Mélin, Christophe Krzeminski, Fabrizio Cleri
The localised deformation of molecular monolayers constrained between the spherical surfaces of Au nanoparticles is studied by means of molecular dynamics simulations. Alkyl or polyethylene glycol long-chain molecules were homogeneously distributed over the curved Au surface, pushed against each other by repeated cycles of force relaxation and constant-volume equilibration, at temperatures increasing from 50 to 300K, before being slowly quenched down to near-zero temperature. Plots of minimum configurational energy can be obtained as a function of the nanoparticle distance, according to different directions of approach; therefore, such simulations describe a range of deformations, from perfectly uniaxial compression, to a combination of compression and shear...
February 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28221806/absorption-and-quantum-yield-of-single-conjugated-polymer-meh-ppv-molecules
#20
Lei Hou, Subhasis Adhikari, Yuxi Tian, Ivan G Scheblykin, Michel Orrit
We simultaneously measured the absorption and emission of single conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) molecules in a PMMA matrix using near-critical xenon to enhance the photothermal contrast for direct absorption measurements. We directly measured the number of monomers and the quantum yield of single conjugated polymer molecules. Simultaneous absorption and emission measurements provide new insight into the photophysics of single conjugated polymers under optical excitation: quenching in larger molecules is more efficient than that of smaller ones...
February 21, 2017: Nano Letters
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