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https://www.readbyqxmd.com/read/28345925/metal-insertion-in-a-methylamine-functionalized-zirconium-metal-organic-framework-for-enhanced-carbon-dioxide-capture
#1
A Paulina Gómora-Figueroa, Jarad A Mason, Miguel I Gonzalez, Eric D Bloch, Katie R Meihaus
The reaction of ZrCl4 with 2',3',5',6'-tetramethylamino-p-terphenyl-4,4″-dicarboxylic acid (H2tpdc-4CH2NH2·3HCl) in the presence of NaF affords Zr6O4(OH)2.1F1.9(tpdc-4CH2NH2·3HCl)6 (1), which is a new member of the Zr6O4(OH)4(dicarboxylate linker)12 or UiO-68 family, and exhibits high porosity with BET and Langmuir surface areas of 1910 m(2)/g and 2220 m(2)/g, respectively. Remarkably, fluoride ion incorporation in the zirconium clusters results in increased thermal stability, marking the first example of enhancement in the stability of a UiO framework by this defect-restoration approach...
March 27, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28345900/fluorescence-and-radio-labeling-of-lys-4-nle-17-30-hpp-yields-molecular-tools-for-the-npy-y4-receptor
#2
Stefanie Dukorn, Timo Littmann, Max Keller, Kilian Konrad Kuhn, Chiara Cabrele, Paul Baumeister, Günther Bernhardt, Armin Buschauer
The neuropeptide Y (NPY) Y4 receptor (Y4R) is involved in energy homeostasis and considered as a potential drug target for the treatment of obesity. Only a few molecular tools, i. e., radiolabeled and fluorescent ligands, for the investigation of the Y4R were reported. Previously, [Lys(4)]hPP proved to be an appropriate full-length PP analog to prepare a fluorescent ligand by derivatization at the ε-amino group. To preclude oxidation upon long-term storage, we replaced the two methionine residues in [Lys(4)]hPP by norleucine and prepared the corresponding [(3)H]propionylated ([(3)H]12) and cyanine labeled (13) peptides, which were characterized and compared with a set of reference compounds in binding (Y1, Y2, Y4 and Y5 receptors) and functional (luciferase gene reporter, β-arrestin-1, -2) Y4R assays...
March 27, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28345892/a-silver-specific-dnazyme-with-a-new-silver-aptamer-and-salt-promoted-activity
#3
Runjhun Saran, Kimberly Kleinke, Wenhu Zhou, Tianmeng Yu, Juewen Liu
Most RNA-cleaving DNAzymes require a metal ion to interact with the scissile phosphate for activity. Therefore, few unmodified DNAzymes work with thiophilic metals due to their low affinity to phosphate. Recently, an Ag+-specific Ag10c DNAzyme was reported via in vitro selection. Herein, the Ag10c is characterized to rationalize the role of the strongly thiophilic Ag+. Systematic mutation studies indicate that the Ag10c is a highly conserved DNAzyme and its Ag+ binding is unrelated to C-Ag+-C interaction. Its activity is enhanced with Na+ concentrations of buffer...
March 27, 2017: Biochemistry
https://www.readbyqxmd.com/read/28345722/eu-2-eu-3-valence-transition-in-double-eu-and-na-doped-pbse-from-transport-magnetic-and-electronic-structure-studies
#4
Bartlomiej Wiendlocha, SunPhil Kim, Yeseul Lee, Bin He, Gloria Lehr, Mercouri G Kanatzidis, Donald T Morelli, Joseph P Heremans
The Eu atoms in Pb1-xEuxSe have long been assumed to be divalent. We show that p-type doping of this magnetic semiconductor alloy with Na can modify the effective Eu valence: a mixed, Eu(2+)-Eu(3+) state appears in Pb1-x-yEuxNaySe at particular values of y. Magnetization, carrier concentration, resistivity, and thermopower of Pb1-x-yEuxNaySe are reported for a number of samples with different x and y. A pronounced increase in thermopower at a given carrier concentration was identified and attributed to the presence of enhanced ionized impurity scattering...
March 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28345204/insight-into-ion-transfer-through-the-sub-nanometer-channels-in-zeolitic-imidazolate-frameworks
#5
Ze-Yu Jiang, Hai-Ling Liu, Saud Asif Ahmed, Sumaira Hanif, Shi-Bin Ren, Jing-Juan Xu, Hong-Yuan Chen, Xing-Hua Xia, Kang Wang
A crack-free sub-nanometer composite structure for the study of ion transfer was constructed by in situ growth of ZIF-90 [Zn(ICA)2 , ICA=Imidazole-2-carboxaldehyde] on the tip of a glass nanopipette. The potential-driven ion transfer through the sub-nanometer channels in ZIF-90 is strongly influenced by the pH of the solution. A rectification ratio over 500 is observed in 1 m KCl solution under alkaline conditions (pH 11.58), which is the highest value reported under such a high salt concentration. Fluorescence experiments show the super-high rectification ratio under alkaline conditions results from the strong electrostatic interaction between ions and the sub-nanometer channels of ZIF-90...
March 27, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28343244/a-new-reactive-1-8-naphthalimide-derivative-for-highly-selective-and-sensitive-detection-of-hg-2
#6
Feng Lv, Yufen Chen, Tengxuan Tang, Yuhua Chen, Dongmei Xu
A 1,8-naphthalimide derivative with a reactive aliphatic hydroxyl was designed and synthesized as a fluorescent probe. Its structure was characterized by IR, (1)H NMR, (13)C NMR, LC-MS and HPLC. The probe showed high selectivity and sensitivity to Hg(2+) over other metal ions such as Pb(2+), Na(+), K(+), Cd(2+), Cr(3+), Zn(2+), Cu(2+), Ni(2+), Ca(2+), Fe(3+), Fe(2+), Co(2+), Mn(2+) and Mg(2+) in MeCN/H2O (15/85, v/v). The increase in fluorescence intensity was linearly proportional to the concentration of Hg(2+) in the range of 18-40 μM with a detection limit of 1...
March 25, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28341196/the-use-of-intraosseous-needles-for-injection-of-contrast-media-for-computed-tomographic-angiography-of-the-thoracic-aorta
#7
Michael Winkler, Cynthia Talley, Connor Woodward, Alexander Kingsbury, Frank Appiah, Hossam Elbelasi, Kevin Landwher, Xingzhe Li, Dominik Fleischmann
BACKGROUND: The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI). METHODS: All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR)...
March 16, 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28340737/efficient-extraction-of-low-abundance-peptides-from-digested-proteins-and-simultaneous-exclusion-of-large-sized-proteins-with-novel-hydrophilic-magnetic-zeolitic-imidazolate-frameworks
#8
Man Zhao, Yiqin Xie, Hemei Chen, Chunhui Deng
Zeolitic imidazolate frameworks (ZIFs) are composed of tetrahedral transition metal ions and imidazolate type organic linkers. This kind of metal organic frameworks (MOFs) combines the unique properties of both zeolites and MOFs. Furthermore, ZIFs can be assembled under mild biocompatible conditions. These advantages make them be primarily studied for biochemical analysis. In this work, polydopamine-modified hydrophilic magnetic ZIFs were synthesized in a simple and mild way for the efficient extraction of low-abundance peptides...
May 15, 2017: Talanta
https://www.readbyqxmd.com/read/28339251/distinct-turbulence-saturation-regimes-in-stellarators
#9
G G Plunk, P Xanthopoulos, P Helander
In the complex 3D magnetic fields of stellarators, ion-temperature-gradient turbulence is shown to have two distinct saturation regimes, as revealed by petascale numerical simulations and explained by a simple turbulence theory. The first regime is marked by strong zonal flows and matches previous observations in tokamaks. The newly observed second regime, in contrast, exhibits small-scale quasi-two-dimensional turbulence, negligible zonal flows, and, surprisingly, a weaker heat flux scaling. Our findings suggest that key details of the magnetic geometry control turbulence in stellarators...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28338317/kinetics-and-mechanism-of-the-oxidation-of-thiourea-dioxide-by-iodine-in-a-slightly-acidic-medium
#10
Li Xu, László Valkai, Alena A Kuznetsova, Sergei V Makarov, Attila K Horváth
The thiourea dioxide (TDO)-iodine reaction was investigated spectrophotometrically monitoring the consumption of total amount of iodine at 468 nm, at T = 25.0 ± 0.1 °C, and at 0.5 M ionic strength in buffered slightly acidic medium. The nitrogen- and carbon-containing products were found to be ammonium ion and dissolved carbon dioxide, respectively, while from sulfur part sulfate ion was exclusively detected, when fresh TDO solution was used. The stoichiometry of the reaction was established as 2I2 + TDO + 4H2O → SO4(2-) + 2NH4(+) + 4I(-) + CO2 + 4H(+) indicating a strict 2:1 stoichiometric ratio...
March 24, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28337691/purification-and-characterization-of-elizabethkingia-l-amino-acid-esterase-an-enzyme-useful-for-enzymatic-synthesis-of-the-dipeptide-valyl-glycine
#11
Takahiro Tanaka, Kazuyoshi Takagi, Hossain Md Saddam, Yoichi Takeda, Mamoru Wakayama
Valyl-glycine (Val-Gly) is useful as a synthetic substrate of γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly), which exhibits a strong taste of "kokumi." For efficient enzymatic synthesis of Val-Gly from valine methylester and glycine using L-amino acid esterase (LAE), we screened microorganisms producing LAE with synthetic activity toward Val-Gly. Among 17 isolates showing LAE activity, Elizabethkingia sp. TT1, which was identified by 16S rDNA sequence analysis, showed the highest synthetic activity toward Val-Gly...
March 24, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28337581/high-lactic-acid-and-fructose-production-via-mn-2-mediated-conversion-of-inulin-by-lactobacillus-paracasei
#12
Kaloyan Petrov, Luiza Popova, Penka Petrova
Lactobacillus paracasei DSM 23505 is able to produce high amounts of lactic acid (LA) by simultaneous saccharification and fermentation (SSF) of inulin. Aiming to obtain the highest possible amounts of LA and fructose, the present study is devoted to evaluate the impact of bivalent metal ions on the process of inulin conversion. It was shown that Mn(2+) strongly increases the activity of the purified key enzyme β-fructosidase. In vivo, batch fermentation kinetics revealed that the high Mn(2+) concentrations accelerated inulin hydrolysis by raise of the inulinase activity, and increased sugars conversion to LA through enhancement of the whole glycolytic flux...
March 23, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28335500/comparison-of-two-types-of-overoxidized-pedot-films-and-their-application-in-sensor-fabrication
#13
Yun Hui, Chao Bian, Jinfen Wang, Jianhua Tong, Shanhong Xia
Poly(3,4-ethylenedioxythiophene) (PEDOT) films were prepared by electro-oxidation on Au microelectrodes in an aqueous solution. Electrolyte solutions and polymerization parameters were optimized prior to overoxidation. The effect of overoxidation time has been optimized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which results in the film overoxidized for 45 s at 1.35 V presenting a strong adsorption. The other one-step overoxidation film prepared by direct CV ranging from -0...
March 19, 2017: Sensors
https://www.readbyqxmd.com/read/28335258/nanostructures-derived-from-starch-and-chitosan-for-fluorescence-bio-imaging
#14
Yinxue Zu, Jingran Bi, Huiping Yan, Haitao Wang, Yukun Song, Bei-Wei Zhu, Mingqian Tan
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs...
July 5, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334668/effect-of-glutamic-acid-on-copper-sorption-onto-kaolinite-batch-experiments-and-surface-complexation-modeling
#15
Lotfollah Karimzadeh, Robert Barthen, Madlen Stockmann, Marion Gruendig, Karsten Franke, Johanna Lippmann-Pipke
High carbonate content of the European Kupferschiefer ore deposits is a challenge for acid copper leaching (pH ≤ 2). Therefore investigating the mobility behavior of Cu(II) under conditions related to an alternative, neutrophil biohydrometallurgical Cu(II) leaching approach is of interest. As glutamic acid (Glu) might be present as a component in the growth media, we studied its effects on the adsorption of Cu(II) onto kaolinite. The binary and ternary batch sorption measurements of Cu(II) and Glu onto kaolinite were performed in the presence of 10 mM NaClO4 as background electrolyte and at a pH range from 4 to 9...
March 20, 2017: Chemosphere
https://www.readbyqxmd.com/read/28333456/calixsmaragdyrin-a-versatile-ligand-for-coordination-complexes
#16
Tamal Chatterjee, Brian Molnar, G G Theophall, Way-Zen Lee, K V Lakshmi, Mangalampalli Ravikanth
The Ru(II) and BF2 complexes of calixsmaragdyrin were prepared under simple reaction conditions and characterized by HR-MS, 1D and 2D NMR spectroscopy, optical spectroscopy, and electrochemistry, and the structure of the Ru(II) complex of calixsmaragdyrin was elucidated by X-ray crystallography. The crystal structure of the Ru(II) complex revealed that the Ru(II) ion is hexacoordinate with the three pyrrole nitrogen ligands from the tripyrrin unit of the calixsmaragdyrin macrocycle, and the remaining coordination sites of Ru(II) ion were occupied by two carbonyl groups and one hydroxyl (-OH) group...
March 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28333380/smooth-muscle-ion-channels-and-regulation-of-vascular-tone-in-resistance-arteries-and-arterioles
#17
Nathan R Tykocki, Erika M Boerman, William F Jackson
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28333049/uranium-biosorption-from-aqueous-solution-by-the-submerged-aquatic-plant-hydrilla-verticillata
#18
Zheng-Ji Yi, Jun Yao, Mi-Jia Zhu, Hui-Lun Chen, Fei Wang, Xing Liu
The biosorption characteristics of U(VI) from aqueous solution onto a nonliving aquatic macrophyte, Hydrilla verticillata (dry powder), were investigated under various experimental conditions by using batch methods. Results showed that the adsorption reached equilibrium within 60 min and the experimental data were well fitted by the pseudo-first-order kinetic model. U(VI) adsorption was strongly pH dependent, and the optimum pH for U(VI) removal was 5.5. Isotherm adsorption data displayed good correlation with the Langmuir model, with a maximum monolayer adsorption capacity of 171...
March 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28330323/modification-of-sargassum-angustifolium-by-molybdate-during-a-facile-cultivation-for-high-rate-phosphate-removal-from-wastewater-structural-characterization-and-adsorptive-behavior
#19
Firozeh Saberzadeh Sarvestani, Hossein Esmaeili, Bahman Ramavandi
In this paper, a new and facile approach for molybdate loading in the brown algae of Sargassum angustifolium is introduced. The molybdate ions were entered into the algae body during a short cultivation to produce algae-Mo as a novel adsorbent for eliminating phosphate ions from synthetic and real wastewaters. Results of the surface analysis showed that molybdate loading onto the algae was successfully performed. Herein, basic variables, such as initial solution pH, adsorbent dosage, contact time, phosphate concentration, and temperature, were investigated in detail to assess the phosphate adsorption performance of algae-Mo...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330261/purification-and-characterization-of-laccase-from-marasmius-species-bbkav79-and-effective-decolorization-of-selected-textile-dyes
#20
A B Vantamuri, B B Kaliwal
A novel laccase-producing white-rot fungus, Marasmius sp. BBKAV79 (Genbank Accession Number-KP455496, KP455497), was isolated and subjected to purification, characterization and dye decolorization study. The purified enzyme was obtained with a specific activity of 0.226 U mg(-1) protein and a final yield of 13.5 %. The enzyme was found to be a monomeric protein with a molecular mass of ~75 kDa as estimated by non-denaturing polyacrylamide gel electrophoresis (PAGE) and further confirmed with zymogram analysis...
December 2016: 3 Biotech
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