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https://www.readbyqxmd.com/read/28431285/two-benzoyl-coumarin-amide-fluorescence-chemosensors-for-cyanide-anions
#1
Zian Wang, Qianqian Wu, Jiale Li, Shuang Qiu, Duxia Cao, Yongxiao Xu, Zhiqiang Liu, Xueying Yu, Yatong Sun
Two new benzoyl coumarin amide derivatives with ortho hydroxyl benzoyl as terminal group have been synthesized. Their photophysical properties and recognition properties for cyanide anions in acetonitrile have also been examined. The influence of electron donating diethylamino group in coumarin ring and hydroxyl in benzoyl group on recognition properties was explored. The results indicate that the compounds can recognize cyanide anions with obvious absorption and fluorescence spectral change and high sensitivity...
April 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28430500/thermalization-and-return-to-equilibrium-on-finite-quantum-lattice-systems
#2
Terry Farrelly, Fernando G S L Brandão, Marcus Cramer
Thermal states are the bedrock of statistical physics. Nevertheless, when and how they actually arise in closed quantum systems is not fully understood. We consider this question for systems with local Hamiltonians on finite quantum lattices. In a first step, we show that states with exponentially decaying correlations equilibrate after a quantum quench. Then, we show that the equilibrium state is locally equivalent to a thermal state, provided that the free energy of the equilibrium state is sufficiently small and the thermal state has exponentially decaying correlations...
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28430490/diffused-vorticity-and-moment-of-inertia-of-a-spin-orbit-coupled-bose-einstein-condensate
#3
Sandro Stringari
By developing the hydrodynamic theory of spinor superfluids, we calculate the moment of inertia of a harmonically trapped Bose-Einstein condensate with spin-orbit coupling. We show that the velocity field associated with the rotation of the fluid exhibits diffused vorticity, in contrast to the irrotational behavior characterizing a superfluid. Both Raman-induced and Rashba spin-orbit couplings are considered. In the first case the moment of inertia takes the rigid value at the transition between the plane wave and the single minimum phase, while in the latter case the rigid value is achieved in the limit of isotropic Rashba coupling...
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28430440/insights-on-the-physical-state-reached-by-an-active-pharmaceutical-ingredient-upon-high-energy-milling
#4
Benjamin Schammé, Xavier Monnier, Nicolas Couvrat, Laurent Delbreilh, Valérie Dupray, Eric Dargent, Gérard Coquerel
In this article, we study the physicochemical transformations of crystalline Quinidine upon high-energy milling. The investigations have been achieved by classical, high performance and fast scanning calorimetry combined with broadband dielectric spectroscopy and X-ray powder diffraction. As evolution of crystalline Quinidine with time of milling revealed a prominent sub-Tg cold-crystallization phenomenon, independent and complementary analytical techniques were implemented. Fast scanning calorimetry was performed for the first time on a milled pharmaceutical compound to postpone the crystallization event to higher temperatures...
April 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28429837/fluorescence-based-sensor-for-selective-and-sensitive-detection-of-amoxicillin-amox-in-aqueous-medium-application-to-pharmaceutical-and-biomedical-analysis
#5
Samadhan P Pawar, Laxman S Walekar, Dattatray B Gunjal, Dattatray K Dalavi, Anil H Gore, Prashant V Anbhule, Shivajirao R Patil, Govind B Kolekar
We here for the first time demonstrate an analytical approach for the highly selective and sensitive detection of amoxicillin (Amox) in aqueous medium based on the fluorescence quenching of quantum dots (QDs). The change in fluorescence intensity of mercaptopropionic acid-capped cadmium sulphide (MPA-CdS) QDs is attributed to the increasing concentration of Amox. The results show that the fluorescence quenching of QDs by Amox takes place through both static and dynamic types of quenching mechanism. The fluorescence quenching of QDs with increase in concentration of Amox shows the linear range between 5 μg ml(-1) and 30 μg ml(-1) and the limit of detection (LOD) is 5...
April 21, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28428126/interactions-of-tetracyclines-with-ovalbumin-the-main-allergen-protein-from-egg-white-spectroscopic-and-electrophoretic-studies
#6
Maria Dayanne de A Dantas, Humberto de Araújo Tenório, Thiago Inácio B Lopes, Hugo Juarez V Pereira, Anita J Marsaioli, Isis M Figueiredo, Josué Carinhanha Caldas Santos
The interactions of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) with ovalbumin (OVA), the main allergen protein of egg white, were investigated by molecular spectroscopy and electrophoresis at three pH conditions (1.5, 4.6 and 7.4). Molecular and synchronous fluorescence, UV-vis spectroscopy, electrophoresis and (1)H NMR were used to study the interaction process. Tetracyclines interact with ovalbumin fluorescence by a static quenching mechanism with non-fluorescent complex formation changing the native protein structure...
April 17, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28427650/effect-of-ultrasound-on-the-interaction-between-epicatechin-gallate-and-bovine-serum-albumin-in-a-model-wine
#7
Qing-An Zhang, Xi-Zhe Fu, Juan Francisco García Martín
Ultrasound is considered as a potential novel technique for improving the quality of some wines. In this paper, a model wine firstly was constructed with the standards of (-)-epicatechin gallate (ECG) and bovine serum albumin (BSA) as target compounds. Then, the experiments were conducted to investigate the effect of ultrasonic irradiation on the binding properties between ECG and BSA including quenching mechanism, binding parameters, binding forces, energy transfer distance and conformational changes determined by spectral analysis...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427044/on-the-reverse-micelle-effect-in-liquid-scintillation-counting
#8
Youcef Nedjadi, Jean-Pascal Laedermann, François Bochud, Claude Bailat
This work looks into the tracks of electrons in nanoemulsive scintillating media using the Monte Carlo Geant4-DNA code which simulates event-by-event interactions of electrons in liquid water down to the eV, without resorting to the condensed history method. It demonstrates that the average number of micelles in which electrons deposit energy is quite large, increasing with their emission energy, decreasing with micelle size, and rising with micelle concentration. The probability of an electron ending its track in a micelle is found to be rather large and micelle size-dependent below 1keV, and approximating the aqueous fraction at higher energies...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28426740/uncovering-the-molecular-and-physiological-processes-of-anticancer-leads-binding-human-serum-albumin-a-physical-insight-into-drug-efficacy
#9
Chuanbo Liu, Zuojia Liu, Jin Wang
Human serum albumin (HSA) has its ability to bind drug molecules and influence their efficacies. Although anticancer leads NSC48693 and NSC290956 functioned at the same mechanism, the drug efficacies were obviously distinct. To gain insight into the distinct drug efficacy, the molecular and physiological processes of anticancer leads binding HSA have been investigated via a combined experimental and theoretical approach. The binding site, as characterized by fluorescence quenching and molecular modeling, is found to be located at site II in subdomain III A for NSC48693 with tight binding and at site FA1 in subdomain I B for NSC290956 with negatively cooperative binding, respectively...
2017: PloS One
https://www.readbyqxmd.com/read/28426322/formative-research-to-design-a-promotional-campaign-to-increase-drinking-water-among-central-american-latino-youth-in-an-urban-area
#10
Nicole Barrett, Uriyoán Colón-Ramos, Allison Elkins, Ivonne Rivera, W Douglas Evans, Mark Edberg
Latinos consume more sugary drinks and less water than other demographic groups. Our objective was to understand beverage choice motivations and test promotional concepts that can encourage Central American Latino urban youth to drink more water. Two rounds of focus group discussions were conducted (n = 10 focus groups, 61 participants, 6-18 years old). Data were transcribed verbatim and analyzed using inductive and deductive coding approaches. Youth motivations for drinking water were shaped by level of thirst, weather, energy, and perceptions of health benefits...
April 20, 2017: Journal of Health Communication
https://www.readbyqxmd.com/read/28426230/photophysics-and-excited-state-properties-of-cyclometalated-iridium-iii-platinum-ii-and-iridium-iii-iridium-iii-bimetallic-complexes-bridged-by-dipyridylpyrazine
#11
Yang-Jin Cho, So-Yoen Kim, Chang Min Choi, Nam Joon Kim, Chul Hoon Kim, Dae Won Cho, Ho-Jin Son, Chyongjin Pac, Sang Ook Kang
We investigated the electrochemical and excited-state properties of 2,3-bis(2-pyridyl)pyrazine (dpp)-bridged bimetallic complexes, (L)2Ir-dpp-PtCl [1, L = 2-(4',6'-difluorophenyl)pyridinato-N,C(2) (dfppy); 2, L = 2-phenylpyridinato-N,C(2) (ppy)] and [(L)2Ir]2(dpp) [3, L = dfppy; 4, L = ppy] compared to monometallic complexes, (L)2Ir-dpp (5, L = dfppy; 6, L = ppy) and dpp-PtCl (dpp-Pt(II)Cl2; 7). The single-crystal X-ray crystallographic structures of 1, 3, 5, and 6 showed that 1 and 3 have approximately coplanar structures of the dpp unit, while the noncoordinated pyridine ring of dpp in 5 and 6 is largely twisted with respect to the pyrazine ring...
April 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28426062/a-sandwich-shaped-m3l2-zinc-ii-complex-containing-1-3-5-tris-dimethyl-pyridin-3-yl-silyl-benzene-selective-photoluminescence-recognition-of-diiodomethane
#12
Sangseok Lee, Haeri Lee, Ok-Sang Jung
Self-assembly of Zn(ClO4)2 with 1,3,5-tris(dimethyl(pyridin-3-yl)silyl)benzene (L) as a new C3-symmetric tridentate N-donor gives rise to a discrete sandwich-shaped M3L2 architecture, [Zn3(μ-OH)3L2](ClO4)3·4CH3CN·2H2O. Its blue photoluminescence is significantly quenched only by CH2I2 among the various small molecules, CH2Cl2, CH2Br2, CHCl3, 1,2-dichloroethane, EtOH, CH3CN, benzene, toluene, and phenol.
April 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28425557/dual-spectra-band-emissive-eu-2-mn-2-co-activated-alkaline-earth-phosphates-for-indoor-plant-growth-novel-phosphor-converted-leds
#13
Young Jun Yun, Jin Kyu Kim, Ji Young Ju, Seul Ki Choi, Woon Ik Park, Jae Yong Suh, Ha-Kyun Jung, Yongseon Kim, Sungho Choi
This paper reports designing a novel single composition blue/red color illuminating phosphor followed by fabricating "smart" agricultural/horticultural LED lighting. Color-tunable Eu(2+)/Mn(2+) co-activated alkaline earth phosphates, Na(Sr,Ba)PO4 and Ca3Mg3(PO4)4, are considered, and the stable doping sites for the corresponding activators are identified by using first-principle DFT calculations. We can realize the designated color purity with stable thermal quenching preserved luminescence behavior is induced by the Eu(2+) center positioned at different coordination states with intermixed Sr(2+)/Ba(2+) sites in Na(Sr,Ba)PO4 hosts...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28425522/red-luminescence-control-of-eu-iii-complexes-by-utilizing-the-multi-colored-electrochromism-of-viologen-derivatives
#14
Kenji Kanazawa, Yuta Komiya, Kazuki Nakamura, Norihisa Kobayashi
The electroresponsive switching of red photoluminescence based on the electrochemical coloration of cyan-magenta-green (CMG) viologen components was achieved by combining a luminescent Eu(3+) chelate and viologen derivatives, resulting in CMG coloration in a single cell. The cell coloration was controlled by an electrochromic (EC) reaction, which also modulated the photoluminescence of the Eu(3+) chelate with high contrast, by transferring energy from the excited state of the Eu(3+) ion to the colored states of EC molecules...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28425025/light-induced-formation-of-dimeric-lhcii
#15
Ewa Janik, Joanna Bednarska, Karol Sowinski, Rafal Luchowski, Monika Zubik, Wojciech Grudzinski, Wieslaw I Gruszecki
It emerges from numerous experiments that LHCII, the major photosynthetic antenna complex of plants, can appear not only in the trimeric or monomeric states but also as a dimer. We address the problem whether the dimeric form of the complex is just a simple intermediate element of the trimer-monomer transformation or if it can also be a physiologically relevant molecular organization form? Dimers of LHCII were analyzed with application of native electrophoresis, time-resolved fluorescence spectroscopy, and fluorescence correlation spectroscopy...
April 19, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28424524/hqia-a-novel-quorum-quenching-enzyme-which-expands-the-ahl-lactonase-family
#16
Marta Torres, Stéphane Uroz, Rafael Salto, Laure Fauchery, Emilia Quesada, Inmaculada Llamas
The screening of a metagenomic library of 250,000 clones generated from a hypersaline soil (Spain) allowed us to identify a single positive clone which confers the ability to degrade N-acyl homoserine lactones (AHLs). The sequencing of the fosmid revealed a 42,318 bp environmental insert characterized by 46 ORFs. The subcloning of these ORFs demonstrated that a single gene (hqiA) allowed AHL degradation. Enzymatic analysis using purified HqiA and HPLC/MS revealed that this protein has lactonase activity on a broad range of AHLs...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28423990/self-assembled-nanogel-of-cholesterol-bearing-xyloglucan-as-a-drug-delivery-nanocarrier
#17
Shin-Ichi Sawada, Hiroko Yukawa, Shigeo Takeda, Yoshihiro Sasaki, Kazunari Akiyoshi
Xyloglucan (XG) is a multibranched polysaccharide consisting of a main chain β-1,4-glucan with xylose and galactose side chains. In this study, cholesterol-bearing XG (CHXG) was synthesized by the reaction of XG with cholesteryl N- (6-isocyanatohexyl) carbamate. The CHXG molecules self-assembled in water to form nanogels consisting of about 100 molecules of XG, and were characterized using differential light scattering and transmission electron microscopy. The number of cholesteryl groups per physical cross-linking site was estimated using a fluorescence quenching method...
April 20, 2017: Journal of Biomaterials Science. Polymer Edition
https://www.readbyqxmd.com/read/28422512/ultrafast-spectroscopic-investigation-of-energy-transfer-in-site-directed-mutants-of-the-fenna-matthews-olson-fmo-antenna-complex-from-chlorobaculum-tepidum
#18
Nikki Cecil Macasinag Magdaong, Rafael G Saer, Dariusz M Niedzwiedzki, Robert E Blankenship
Ultrafast transient absorption (TA) and time-resolved fluorescence (TRF) spectroscopic studies were performed on several mutants of the bacteriochlorophyll (BChl) a-containing Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum. These mutants were generated to perturb a particular BChl a site and determine its effects on the optical spectroscopic properties of the pigment-protein complex. Measurements conducted at 77 K under both oxidizing and reducing conditions revealed changes in the dynamics of the various spectral components as compared to the dataset from wild-type FMO...
April 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28422382/quantum-dots-based-fluorescence-resonance-energy-transfer-biosensor-for-monitoring-cell-apoptosis
#19
Chunchuan Gu
The development of advanced methods for accurately monitoring cell apoptosis has extensive significance in the diagnostic and pharmaceutical fields. In this study, we developed a rapid, sensitive and selective approach for the detection of cell apoptosis by combining the site-specific recognition and cleavage of the DEVD-peptide with quantum dots (QDs)-based fluorescence resonance energy transfer (FRET). Firstly, biotin-peptide was conjugated on the surface of AuNPs to form AuNPs-pep through the formation of an Au-S bond...
April 19, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28422117/ultrahigh-responsivity-and-detectivity-graphene-perovskite-hybrid-phototransistors-by-sequential-vapor-deposition
#20
Po-Han Chang, Shang-Yi Liu, Yu-Bing Lan, Yi-Chen Tsai, Xue-Qian You, Chia-Shuo Li, Kuo-You Huang, Ang-Sheng Chou, Tsung-Chin Cheng, Juen-Kai Wang, Chih-I Wu
In this work, graphene-methylammonium lead iodide (MAPbI3) perovskite hybrid phototransistors fabricated by sequential vapor deposition are demonstrated. Ultrahigh responsivity of 1.73 × 10(7) A W(-1) and detectivity of 2 × 10(15) Jones are achieved, with extremely high effective quantum efficiencies of about 10(8)% in the visible range (450-700 nm). This excellent performance is attributed to the ultra-flat perovskite films grown by vapor deposition on the graphene sheets. The hybrid structure of graphene covered with uniform perovskite has high exciton separation ability under light exposure, and thus efficiently generates photocurrents...
April 19, 2017: Scientific Reports
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