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https://www.readbyqxmd.com/read/29149558/quantification-of-humic-substances-in-natural-water-using-nitrogen-doped-carbon-dots
#1
Yan-Fang Guan, Bao-Cheng Huang, Chen Qian, Han-Qing Yu
Dissolved organic matter (DOM) is ubiquitous in aqueous environments and plays a significant role in pollutant mitigation, transformation and organic geochemical circulation. DOM is also capable of forming carcinogenic by-products in the disinfection treatment processes of drinking water. Thus, efficient methods for DOM quantification are highly desired. In this work, a novel sensor for rapid and selective detection of humic substances (HS), a key component of DOM, based on fluorescence quenching of nitrogen-doped carbon quantum dots was developed...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29149083/co-precipitation-synthesis-and-optical-properties-of-mn-4-doped-hexafluoroaluminate-w-led-phosphors
#2
Tim Senden, Robin G Geitenbeek, Andries Meijerink
Mn(4+)-activated hexafluoroaluminates are promising red-emitting phosphors for white light emitting diodes (w-LEDs). Here, we report the synthesis of Na₃AlF₆:Mn(4+), K₃AlF₆:Mn(4+) and K₂NaAlF₆:Mn(4+) phosphors through a simple two-step co-precipitation method. Highly monodisperse large (~20 μm) smoothed-octahedron shaped crystallites are obtained for K₂NaAlF₆:Mn(4+). The large size, regular shape and small size distribution are favorable for application in w-LEDs. All Mn(4+)-doped hexafluoroaluminates show bright red Mn(4+) luminescence under blue light excitation...
November 17, 2017: Materials
https://www.readbyqxmd.com/read/29148733/fluorescence-and-quenching-assessment-eem-parafac-of-de-facto-potable-reuse-in-the-neuse-river-north-carolina-united-states
#3
Martha J M Wells, Gene A Mullins, Katherine Y Bell, Allegra K Da Silva, Eileen M Navarrete
The Neuse River, North Carolina, U.S., exemplifies a typical de facto potable reuse scenario, where drinking water sources are located downstream of treated wastewater effluent discharges. The study results imply that planned potable water reuse, whether in an indirect or direct potable reuse scenario, might provide better control over water quality than the status quo conditions. Using fluorescence excitation-emission matrix (EEM) measurements, anthropogenic influence of a wastewater treatment plant (WWTP) discharge was observed in samples near the location of drinking water treatment plant (WTP) intakes, eight or more miles downstream of the WWTP, implying that anthropogenic compounds were not fully removed or degraded by natural processes in this reach of the river...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29148728/neutral-luminescent-metal-organic-frameworks-structural-diversification-photophysical-properties-and-sensing-applications
#4
Gouri Chakraborty, Sanjay K Mandal
Utilizing flexible bis(tridentate)polypyridyl ligands, the two new luminescent 2D metal organic frameworks {Zn2(tpbn)(2,6-NDC)2}n (1) and {[Zn2(tphn)(2,6-NDC)2]·4H2O}n (2), where tpbn = N,N',N″,N‴-tetrakis(2-pyridylmethyl)-1,4-diaminobutane, tphn = N,N',N″,N‴-tetrakis(2-pyridylmethyl)-1,6-diaminohexane, and 2,6-H2NDC = 2,6-naphthalenedicarboxylic acid, have been isolated in good yields under solvothermal conditions. Their solid-state molecular structures have been determined by single-crystal X-ray diffractometry...
November 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29148551/tunable-fluorescence-behaviors-of-a-supramolecular-system-based-on-a-fluorene-derivative-and-cucurbit-8-uril-and-its-application-for-atp-sensing
#5
Rongqin Ye, Qianling Cui, Chuang Yao, Ronghua Liu, Lidong Li
In this work, we developed a supramolecular fluorescent system based on host-guest interactions between a fluorene derivative carrying two bispyridinium units (FPy) and cucurbit[8]uril (CB[8]). In aqueous solution, the system showed outstanding tunable emission properties. After being encapsulated into the rigid hydrophobic cavity of the CB[8] host, the fluorescence emission of fluorene had an obvious red-shift with enhanced quantum yield. Interestingly, the emission behavior of the FPy/CB[8] complex showed a two-step self-assembly process when the molar ratio of FPy to CB[8] changed from 1 : 1 to 1 : 2...
November 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29148081/synthesis-antitumor-activity-evaluation-and-dna-binding-study-of-coumarin-based-agents
#6
Kamilia M Amin, Aly M Taha, Riham F George, Nada M Mohamed, Fardous F Elsenduny
A novel series of coumarin-thiadiazole heterocycle derivatives was synthesized by the nucleophilic substitution reaction. The synthesized compounds were structurally verified by IR, (1) H NMR, (13) C NMR, mass spectra, and elemental analyses. The antitumor activity of the synthesized compounds was evaluated through DNA binding assays and the 60-cell line panel according to the US NCI-DTP protocol or a selection of human tumor cell lines: breast cancer (MCF-7), liver cancer (HepG-2), and colorectal cancer (HCT-116)...
November 17, 2017: Archiv der Pharmazie
https://www.readbyqxmd.com/read/29147748/graphene-quantum-dots-terbium-ions-as-novel-sensitive-and-selective-time-resolved-luminescent-probes
#7
Eulogio J Llorent-Martínez, Gema M Durán, Ángel Ríos, Antonio Ruiz-Medina
We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes...
November 16, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29147027/trapping-pinning-of-colloidal-microspheres-over-glass-substrate-using-surface-features
#8
Praneet Prakash, Manoj Varma
Suspensions of micro/nano particles made of Polystyrene, Poly(methyl methacrylate), Silicon dioxide etc. have been a standard model system to understand colloidal physics. These systems have proved useful insights into phenomena such as self-assembly. Colloidal model systems are also extensively used to simulate many condensed matter phenomena such as dynamics in a quenched disordered system and glass transition. A precise control of particles using optical or holographic tweezers is essential for such studies...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29147000/stable-icg-loaded-upconversion-nanoparticles-silica-core-shell-theranostic-nanoplatform-for-dual-modal-upconversion-and-photoacoustic-imaging-together-with-photothermal-therapy
#9
Ruichan Lv, Depeng Wang, Liyang Xiao, Guanying Chen, Jun Xia, Paras N Prasad
We report here the design and multiple functions of a new hierarchical nanotheronostic platform consisting of an upconversion nanoparticle (UCNP) core: shell with an additional mesoporous silica (mSiO2) matrix load shell containing sealed, high concentration of ICG molecules. We demonstrate that this UCNP@mSiO2-ICG nanoplatform can perform the following multiple functions under NIR excitation at 800 nm: 1) Light harvesting by the UCNP shell containing Nd and subsequent energy transfer to Er in the Core to produce efficient green and red upconversion luminescence for optical imaging; 2) Efficient nonradiative relaxation and local heating produced by concentration quenching in aggregated ICG imbedded in the mesopourous silica shell to enable both photoacoustic imaging and photothermal therapy...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29146982/photonic-simulation-of-entanglement-growth-and-engineering-after-a-spin-chain-quench
#10
Ioannis Pitsios, Leonardo Banchi, Adil S Rab, Marco Bentivegna, Debora Caprara, Andrea Crespi, Nicolò Spagnolo, Sougato Bose, Paolo Mataloni, Roberto Osellame, Fabio Sciarrino
The time evolution of quantum many-body systems is one of the most important processes for benchmarking quantum simulators. The most curious feature of such dynamics is the growth of quantum entanglement to an amount proportional to the system size (volume law) even when interactions are local. This phenomenon has great ramifications for fundamental aspects, while its optimisation clearly has an impact on technology (e.g., for on-chip quantum networking). Here we use an integrated photonic chip with a circuit-based approach to simulate the dynamics of a spin chain and maximise the entanglement generation...
November 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/29146776/light-signaling-dependent-regulation-of-photoinhibition-and-photoprotection-in-tomato
#11
Feng Wang, Nan Wu, Luyue Zhang, Golam Jalal Ahammed, Xiaoxiao Chen, Xun Xiang, Jie Zhou, Xiaojian Xia, Kai Shi, Jingquan Yu, Christine H Foyer, Yanhong Zhou
Photoreceptor-mediated light signaling plays a critical role in plant growth, development, and stress responses but its contribution to the spatial regulation of photoinhibition and photoprotection within the canopy remains unclear. Here, we show that low red/far-red (L-R/FR) ratio light conditions significantly alleviate PSII and PSI photoinhibition in the shade leaves of tomato plants. This protection is accompanied by a phytochrome A (phyA)-dependent induction of LONG HYPOCOTYL 5 (HY5). HY5 binds to the promoter of ABA INSENSITIVE 5 (ABI5), triggering RESPIRATORY BURST OXIDASE HOMOLOG1 (RBOH1)-dependent H2O2 production in the apoplast...
November 16, 2017: Plant Physiology
https://www.readbyqxmd.com/read/29146372/interactions-of-cinnamaldehyde-and-its-metabolite-cinnamic-acid-with-human-serum-albumin-and-interference-of-other-food-additives
#12
Qiaomei Sun, Hongqin Yang, Peixiao Tang, Jiuyang Liu, Wan Wang, Hui Li
Considering the adverse effect of food additives on humans, thorough research of their physiological effects at the molecular level is important. The interactions of cinnamaldehyde (CNMA), a food perfume, and its major metabolite cinnamic acid (CA) with human serum albumin (HSA) were examined by multiple-spectroscopies. NMR analysis revealed CNMA and CA both bound to HSA, and STD-NMR experiments established CNMA and CA primarily interacted with site I and site II of HSA, respectively. The ligands caused strong quenching of HSA fluorescence through a static quenching mechanism, with hydrophobic and electrostatic interaction between CNMA/CA and HSA, respectively...
March 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29146367/corrigendum-to-interactions-between-polyphenols-in-thinned-young-apples-and-porcine-pancreatic-%C3%AE-amylase-inhibition-detailed-kinetics-and-fluorescence-quenching-food-chem-208-2016-51-60
#13
Lijun Sun, Weiqi Chen, Yonghong Meng, Xingbin Yang, Li Yuan, Yurong Guo, Frederick J Warren, Michael J Gidley
No abstract text is available yet for this article.
March 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29145072/pyridoxamine-driven-selective-turn-off-detection-of-picric-acid-using-glutathione-stabilized-fluorescent-copper-nanoclusters-and-its-applications-with-chemically-modified-cellulose-strips
#14
Ravi Patel, Shilpa Bothra, Rajender Kumar, Guido Crisponi, Suban K Sahoo
The present work reports the interaction of various vitamin B6 cofactors with the red emitting glutathione stabilized copper nanoclusters (GSH-CuNCs). Addition of pyridoxamine (PM) resulted a new turn-on band at 410nm due to the possible adsorption over the surface of GSH-CuNCs. The nano-assembly PM-GSH-CuNCs was applied for the selective detection of nitro-aromatic compounds. Upon addition of picric acid (PA), the fluorescence of PM-GSH-CuNCs was selectively quenched at 410nm and ~ 625nm among the other tested nitro-aromatic compounds...
November 9, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29145059/binding-of-naringin-and-naringenin-with-hen-egg-white-lysozyme-a-spectroscopic-investigation-and-molecular-docking-study
#15
Sourav Das, Pooja Ghosh, Sudipta Koley, Atanu Singha Roy
The interactions of naringenin (NG) and naringin (NR) with Hen Egg White Lysozyme (HEWL) in aqueous medium have been investigated using UV-vis spectroscopy, steady-state fluorescence, circular dichroism (CD), Fourier Transform infrared spectroscopy (FT-IR) and molecular docking analyses. Both NG and NR can quench the intrinsic fluorescence of HEWL via static quenching mechanism. At 300K, the value of binding constant (Kb) of HEWL-NG complex (5.596±0.063×10(4)M(-1)) was found to be greater than that of HEWL-NR complex (3...
November 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29144760/multi-spectroscopic-and-theoretical-exploration-on-the-comparative-binding-aspects-of-the-bio-flavonoid-fisetin-with-triple-and-double-helical-forms-of-rna
#16
Sutanwi Bhuiya, Lucy Haque, Rapti Goswami, Suman Das
The interactions of RNA triplex (U.A*U) and duplex (A.U) with the naturally occurring flavonoid fisetin (FTN) have been examined at pH 7.0 using various spectroscopic, viscometric and theoretical studies. Experimental observations showed that the ligand binds with both double and triple helical forms of RNA, although the binding affinity is greater for the triplex structure (5.94106 M-1) compared to the duplex counterpart (1.0105 M-1). Thermal melting experiments revealed that the Hoogsteen base paired third strand of triplex was stabilized to a greater extent (~14 C) compared to the Watson-Crick base paired second strand (~4 C) in presence of FTN...
November 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29144134/haloarene-linked-unsymmetrically-substituted-triarylethenes-small-aiegens-to-detect-nitroaromatics-and-volatile-organic-compounds
#17
Moghal Zubair Khalid Baig, Prabhat Kumar Sahu, Moloy Sarkar, Manab Chakravarty
Unsymmetrically substituted triarylalkenes as aggregation-induced emission-active fluorogens (AIEgens) are sporadically explored by different researchers. In this paper, naphthalene, biphenyl and haloarene-linked new triarylethenes are conveniently synthesized and presented as unsymmetrically substituted extensive π-conjugates to continue the discovery of small molecules as new AIEgens. Moreover, fluorophores attached to haloarenes are noteworthy but such compounds are barely investigated as AIEgens. The possible mechanism underlying this AIE-behavior has also been addressed by the support of experimental/theoretical outcomes...
November 16, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29143988/synthesis-and-optical-properties-of-phenanthroline-derived-schiff-base-like-dinuclear-ru-ii-ni-ii-complexes
#18
Hannah Kurz, Charles Lochenie, Kristina G Wagner, Sandra Schneider, Matthias Karg, Birgit Weber
Two phenanthroline-derived Schiff base-like ligands with a covalently-linked Ru(II) phosphorescent unit were synthesised and converted into bimetallic Ru(II)-Ni(II) complexes. The optical properties were studied to examine a possible photoluminescence quenching through a non-radiative energy transfer upon Coordination Induced Spin State Switch (CISSS) at the Ni(II) centre. Therefore the metalloligands and the Ni(II) complexes were studied by UV-Vis absorbance as well as steady-state and time-resolved emission spectroscopy in MeCN and pyridine solutions...
November 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29142807/silver-nanoparticle-human-hemoglobin-interface-time-evolution-of-the-corona-formation-and-interaction-phenomenon
#19
A K Bhunia, T Kamilya, S Saha
In this paper, we have used spectroscopic and electron microscopic analysis to monitor the time evolution of the silver nanoparticles (Ag NP)-human hemoglobin (Hb) corona formation and to characterize the interaction of the Ag NPs with Hb. The time constants for surface plasmon resonance binding and reorganization are found to be 9.51 and 118.48 min, respectively. The drop of surface charge and the increase of the hydrodynamic diameter indicated the corona of Hb on the Ag NP surface. The auto correlation function is found to broaden with the increasing time of the corona formation...
2017: Nano Convergence
https://www.readbyqxmd.com/read/29140702/influence-of-the-carotenoid-composition-on-the-conformational-dynamics-of-photosynthetic-light-harvesting-complexes
#20
Marijonas Tutkus, Jevgenij Chmeliov, Danielis Rutkauskas, Alexander V Ruban, Leonas Valkunas
Non-photochemical quenching (NPQ) is the major self-regulatory mechanism of green plant, performed on a molecular level to protect them from an over-excitation during the direct sunlight. It is believed that NPQ becomes available due to conformational dynamics of the light-harvesting photosynthetic complexes and involves a direct participation of carotenoids. In this work, we perform a single-molecule microscopy on major light-harvesting complexes (LHCII) from different Arabidopsis thaliana mutants exhibiting various carotenoid composition...
November 15, 2017: Journal of Physical Chemistry Letters
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