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acid base strong ion

Adrien Marchand, Valérie Gabelica
G-quadruplexes adopt various folding topologies, but information on their folding pathways remains scarce. Here, we used electrospray mass spectrometry to detect and quantify the specifically bound potassium ions, and circular dichroism to characterize the stacking topology of each ensemble. For human telomeric (hTel) sequences containing the d((GGGTTA)3GGG) core, K(+) binding affinity and cooperativity strongly depends on the chosen construct. The shortest sequences bind only one K(+) at low KCl concentration, and this 2-quartet G-quadruplex is antiparallel...
October 19, 2016: Nucleic Acids Research
Ding Zhou, Yuechen Zhai, Songnan Qu, Di Li, Pengtao Jing, Wenyu Ji, Dezhen Shen, Andrey L Rogach
Carbon nanodots (CNDs)@BaSO4 hybrid phosphors are fabricated in an easy and low-cost process by sequentially assembling Ba(2+) and SO4(2-) ions onto the surface of carbon nanodots through electrostatic attraction. CNDs act as the nucleus to attract these reactive ions and provide the luminescent centers in the hybrid phosphors. This strategy is versatile for a variety of negatively charged CNDs with different emission colors. The advantage of the resultant hybrid phosphors is that their luminescence exhibits excellent thermal and photostability, as well as remarkable resistance to strong acid/alkali and common organic solvents...
December 5, 2016: Small
Yanjun Ding, Jiang Ling, Yuchun Qiao, Zhengjian Li, Zongzhao Sun, Jifeng Cai, Yadong Guo, Hua Wang
A rapid, ultrasensitive, and high-throughput fluorimetric microarray method has been developed using hydrophobic pattern as the microarray substrate and 3-aminopropyltriethoxysilane-coupled carboxylic acid calcium (APS-CCA) as the fluorescent probes for sensing Ca(2+) ions in blood. The hydrophobic pattern of the developed Ca(2+) analysis microarray could largely suppress the "coffee-ring" effects to facilitate the better distribution density of testing microspots toward the high-throughput detections, and especially prevent the cross-contamination of the multiple samples between adjacent microspots...
December 5, 2016: Scientific Reports
X Wang, M Ackermann, E Tolba, M Neufurth, F Wurm, Q Feng, S Wang, H C Schröder, W E Müller
Here we show that inorganic polyphosphate (polyP), a polyanionic metabolic regulator consisting of multiple phosphate residues linked by energy-rich phosphoanhydride bonds, is present in the synovial fluid. In a biomimetic approach, to enhance cartilage synthesis and regeneration, we prepared amorphous polyP microparticles with Mg2+ as counterions. The particles were characterised by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) and Fourier transformed infrared spectroscopic (FTIR) analyses. Similar particles were obtained after addition of Mg2+ ions to a solution containing hyaluronic acid, as a major component of the synovial fluid, and soluble Na-polyP...
November 29, 2016: European Cells & Materials
Michael Lever, Christopher J McEntyre, Peter M George, Stephen T Chambers
Choline metabolism is by oxidation to betaine, which is demethylated to N,N-dimethylglycine; dimethylglycine is oxidatively demethylated to sarcosine. This pathway is important for osmoregulation and as a source of methyl groups. We asked whether another metabolite was involved. We synthesized the N-oxide of dimethylglycine (DMGO) by oxidizing dimethylglycine with peracetic acid, and measured DMGO in human plasma and urine by HPLC-MS/MS with positive ion detection, using two chromatography procedures, based on ion exchange and HILIC separations...
November 30, 2016: Biological Chemistry
Carlos Torrente Artero
Metabolic acid-base disorders are common in emergency and critically ill patients. Clinicians may have difficulty recognizing their presence when multiple acid-base derangements are present in a single patient simultaneously. The anion gap and the strong ion gap concepts are useful calculations to identify the components of complex metabolic acid-base associated to the presence of unmeasured anions. This article presents their definition, normal values, indications, limitations, and guidelines for interpretation of changes in the clinical setting...
November 25, 2016: Veterinary Clinics of North America. Small Animal Practice
Wei Cai, Shunbi Xie, Ying Tang, Yaqin Chai, Ruo Yuan, Jin Zhang
A label-free electrochemical biosensor for sensitive detection of miRNA-155 was presented by coupling enzyme-catalyzed in situ generation of electronic mediator for signal introduction with catalytic hairpin assembly (CHA) induced target recycling amplification strategy. In this work, alkaline phosphatase (ALP) was adopted to hydrolyze inactive substrate 1-naphthyl phosphate (NPP) to produce phosphate ion (PO4(3-)), which could further react with acidic molybdate to form abundant molybdophosphate anion (PMo12O40(3-)) on the surface of electrode...
January 15, 2017: Talanta
Haiqiang Wang, Penglu Wang, Xiongbo Chen, Zhongbiao Wu
In this work, protonated titanate nanotubes was performed as a potential useful support and different vanadium precursors (NH4VO3 and VOSO4) were used to synthesize deNOx catalysts. The results showed that VOSO4 exhibited better synergistic effect with titanate nanotubes than NH4VO3, which was caused by the ion-exchange reaction. Then high loading content of vanadium, uniformly active phase distribution, better dispersion of vanadium, more acid sites, better V(5+)/V(4+) redox cycles and superior oxygen mobility were achieved...
November 9, 2016: Journal of Hazardous Materials
Sungwon Kim, Cheonil Park, Byeong-Seok Moon, Hyoun-Ee Kim, Tae-Sik Jang
Owing to the excellent bioactive properties of recombinant human bone morphogenetic proteins (rhBMPs), dentistry considers them as a fascinating adjuvant alternative for enhancing bone regeneration and bone-to-implant junction in the early implantation stages. However, stable loading and delivery efficiency of rhBMPs on the implant surfaces involve major concerns because of the harsh wearing condition under load during implantation. In this study, to achieve successful rhBMP-2 delivery, a nanoporous surface structure is introduced on the sandblasting with large grit and acid-etching (SLA)-treated titanium (Ti) surface via the tantalum (Ta) target-ion induced plasma sputtering (TIPS) technique...
November 23, 2016: Journal of Biomaterials Applications
Francisco Morales-Lara, María Domingo-García, Rafael López-Garzón, María Luz Godino-Salido, Antonio Peñas-Sanjuán, F Javier López-Garzón, Manuel Pérez-Mendoza, Manuel Melguizo
Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials...
2016: Science and Technology of Advanced Materials
Ling Ding, Wenying Lv, Kun Yao, Liming Li, Mengmeng Wang, Guoguang Liu
Humin is the component of humic substances that is recalcitrant to extraction by either strong bases or strong acids, which contains a variety of functional groups that may combine with heavy metal ions. The present study employed humin as an adsorbent to investigate the efficacy of a remediation strategy under the effects of humin-enhanced electrokinetics. Because the cations gravitate toward cathode and anions are transferred to anode, humin was placed in close proximity to the cathode in the form of a package...
November 21, 2016: Environmental Science and Pollution Research International
Caixia Li, Lei Wu, Lixi Chen, Xiangyang Yuan, Yimin Cai, Wen Feng, Ning Liu, Yi Ren, Arijit Sengupta, Mallekav S Murali, Prasanta K Mohapatra, Guohong Tao, Huaqiang Zeng, Songdong Ding, Lihua Yuan
Actinide partitioning is considered as one of the most challenging issues in nuclear waste remediation. Herein, we unravel a novel extraction mode pertinent to the competitive host-guest interactions for highly efficient actinide extraction. The host-guest recognition event involves binding of a room temperature ionic liquid (RTIL), 1-n-octyl-3 methylimidazolium bis(trifluoromethane)sulfonamide (C8mimNTf2), as both the guest and the solvent by the hosts pillar[5]arene-based diglycolamides (P5DGAs) and the subsequent displacement of the guest by a metal ion...
November 22, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Christine E Duval, Timothy A DeVol, Scott M Husson
This contribution describes the synthesis of robust extractive scintillating resin and its use in a flow-cell detector for the direct detection of uranium in environmental waters. The base poly[(4-methyl styrene)-co-(4-vinylbenzyl chloride)-co-(divinylbenzene)-co-(2-(1-napthyl)-4-vinyl-5-phenyloxazole)] resin contains covalently bound fluorophores. Uranium-binding functionality was added to the resin by an Arbuzov reaction followed by hydrolysis via strong acid or trimethylsilyl bromide (TMSBr)-mediated methanolysis...
December 1, 2016: Analytica Chimica Acta
Wenran Wang, Jun Du, Zhenwei Ren, Wenxiang Peng, Zhenxiao Pan, Xinhua Zhong
Increasing QD loading amount on photoanode and suppressing charge recombination are prerequisite for high efficiency quantum dot sensitized solar cells (QDSCs). Herein, a facile technique for enhancing loading amount of QDs on photoanode and therefore improving the photovoltaic performance of the resultant cell devices is developed by pipetting metal salt aqueous solutions on TiO2 film electrode and then evaporating at elevated temperature. The effect of different metal salt solutions were investigated and experimental results indicated that the isoelectric point (IEP) of metal ions influenced the loading amount of QDs and consequently the photovoltaic performance of the resultant cell devices...
October 31, 2016: ACS Applied Materials & Interfaces
Said H Lubbad
Three monoliths based on poly(glycidyl methacrylate-co-divinylbenzene) were prepared in the confines of borosilicate glass columns (100 × 3 mm I.D.). The first monolith was applied for analysis of proteins by reversed-phase high-performance liquid chromatography. It furnished a fast base-line separation for four proteins (ribonuclease A, cytochrome c, α-lactalbumin and myoglobin) in <80 s, with optimum resolution range of 2.11-2.84, and extremely small values of peak width at half height with a range of 1...
October 24, 2016: Journal of Chromatographic Science
Nuno Basílio, Sheiraz Al Bittar, Nathalie Mora, Olivier Dangles, Fernando Pina
3-Deoxyanthocyanidins and their O-β-d-glucosides are natural pigments abundant in black sorghum. O-glycosidation can perturb the acid-base properties of the chromophore and lower its electron density with a large impact on the distribution of colored and colorless forms in aqueous solution. In this work, the influence of O-glycosidation on color is systematically studied from a series of 3-deoxyanthocyanin analogs. The pH- and light-dependent reversible reactions of 7-β-d-glucopyranosyloxy-4'-hydroxyflavylium (P3) and 4'-β-d-glucopyranosyloxy-7-hydroxyflavylium (P5) were completely characterized in mildly acidic solution and compared with the parent aglycone 4',7-dihydroxyflavylium ion and the O-methylethers of P3 and P5...
October 20, 2016: International Journal of Molecular Sciences
Taiping Qing, Xiaoxiao He, Dinggeng He, Zhihe Qing, Kemin Wang, Yanli Lei, Ting Liu, Peng Tang, Yue Li
In this work, we developed a simple, rapid and mild strategy for synthesis of DNA-templated fluorescent gold nanoclusters (AuNCs) through association of gold ions to DNA templates and reduction with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). After systematical investigation on the formation of fluorescent AuNCs by using different DNA templates, C5 DNA was found as the best template for the formation of fluorescent AuNCs in this system. This process could be completed within 5min after the reaction beginning under ambient conditions...
December 1, 2016: Talanta
P Sławuta, G Sapikowski, B Sobieraj
: Buffer systems of blood and tissues, which have the ability to bind with and give up hydrogen ions, participate in maintaining the acid-base balance (ABB) of the organism. According to the classic model, the system of carbonic acid and bicarbonates, where the first component serves the role of an acid and the second a base, determines plasma pH. The so-called Stewart model, which assumes that ions in blood serum can be separated into completely dissociated - nonbuffer and not dissociated - buffer ions which may give up or accept H+ions, also describes the ABB of the organism...
September 1, 2016: Polish Journal of Veterinary Sciences
Justin A Lemkul, Alexander D MacKerell
Mg2+ ions are important in biological systems, particularly in stabilizing compact RNA folds. Mg2+ is strongly polarizing, and representing its interactions in heterogeneous environments is a challenge for empirical force field development. To date, the most commonly used force fields in molecular dynamics simulations utilize a pairwise-additive approximation for electrostatic interactions, which cannot account for the significant polarization response in systems containing Mg2+. In the present work, we refine the interactions of Mg2+ with water, Cl- ions, and nucleic acid moieties using a polarizable force field based on the classical Drude oscillator model...
October 19, 2016: Journal of Physical Chemistry. B
Katy Schäfer, Heiko Ihmels, Cornelia Bohne, Karolina Papera Valente, Anton Granzhan
It is shown by photometric and fluorimetric analysis, along with supporting theoretical calculations, that hydroxy-substituted benzo[b]quinolizinium derivatives display the characteristic features of organic photoacids. Specifically, the experimental and theoretical results confirm the strong acidity of these compounds in the excited state (pKa* < 0). The combination of the prototropic properties of 8- and 9-hydroxybenzo[b]quinolizinium with the particular solvent-solute interactions of the excited acid and its conjugate base leads to a pronounced fluorosolvatochromism, hence the emission maxima shift from 468 nm (8-hydroxybenzo[b]quinolizinium) or 460 nm (9-hydroxybenzo[b]quinolizinium) in CH3CN to 507 and 553 nm in DMF, respectively...
November 1, 2016: Journal of Organic Chemistry
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