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strong ion

Erik Andris, Prokopis Andrikopoulos, Jiří Schulz, Jan Turek, Aleš Růžička, Jana Roithová, Lubomír Rulíšek
Attractive metallophilic (aurophilic, argentophilic, cuprophilic, …) interactions play an important role in arrangement and stabilization of oligonuclear metal ion complexes. We report a combined experimental and theoretical assessment of aurophilic interactions in closed-shell gold(I) dimers. The experimental binding energies were obtained for charged [(LH)AuCl]+…[(L')AuCl] dimers (L is either a phosphine or a N-heterocyclic carbene ligand) in the gas phase. These energies served for benchmarking of correlated quantum chemical calculations (CCSD(T)-calibrated SCS-MP2/CBS method) that were then applied to neutral [(L)AuX]…[(L')AuX] dimers (X = Cl, Br, I)...
January 15, 2018: Journal of the American Chemical Society
Hui Zhao, Yang Wei, Cheng Wang, Rui-Min Qiao, Wanli Yang, Phillip B Messersmith, Gao Liu
The excessive volume changes during cell cycling of Si-based anode in lithium ion batteries impeded its application. One major reason for the cell failure is particle isolation during volume shrinkage in delithiation process, which makes strong adhesion between polymer binder and anode active material particles a highly desirable property. Here, a biomimetic side-chain conductive polymer incorporating catechol, a key adhesive component of the mussel holdfast protein, was synthesized. Atomic force microscopy (AFM) based single molecule force measurements of mussel-inspired conductive polymer binder contacting a silica surface revealed similar adhesion toward substrate when compared with an effective Si anode binder, homo-polyacrylic acid (PAA), with the added benefit of being electronically conductive...
January 15, 2018: ACS Applied Materials & Interfaces
Dandan Jiang, Xiqian Li, Jiutong Ma, Qiong Jia
In this study, we designed a gadolinium-based immobilized metal ion affinity chromatography material for the selective enrichment of phosphopeptides. Gadolinium ion was immobilized on the surface of glutathione-coated magnetic nanoparticles through a facile and effective synthetic route. The adsorbent integrated the advantages of superparamagnetism of Fe3O4 core, good biological compatibility of glutathione, and strong interaction between gadolinium ion and phosphopeptides. It was employed to enrich phosphopeptides from standard protein digests coupled with MALDI-TOF MS...
April 1, 2018: Talanta
Ilya E Zlobin, Yury V Ivanov, Alexander V Kartashov, Vladimir V Kuznetsov
We investigated physiological responses of 7-week-old Norway spruce seedlings to water deficits of different intensities. Hydroponically grown seedlings were subjected to mild (-0.15 MPa), strong (-0.5 and -1.0 MPa) and extreme (-1.5 MPa) water deficit induced by polyethylene glycol 6000, and their growth parameters, water status and physiological activity were analyzed. Seedlings effectively restricted water loss under drought, and even under extreme water deficit, shoot relative water content did not fall below 85%...
January 5, 2018: Environmental Science and Pollution Research International
G Lanaro, G N Patey
Molecular dynamics (MD) simulations are employed to investigate crystal nucleation and growth in oversaturated aqueous LiF solutions. Results obtained for a range of temperatures provide evidence that the rate of crystal growth is determined by a substantial energy barrier (∼49 kJ mol-1) related to the loss of water from the ion hydration shells. Employing direct MD simulations, we do not observe spontaneous nucleation of LiF crystals at 300 K, but nucleation is easily observable in NVT simulations at 500 K...
January 14, 2018: Journal of Chemical Physics
V M Shabaev, D A Glazov, A V Malyshev, I I Tupitsyn
The nuclear recoil effect on the g factor of Li-like ions is evaluated. The one-electron recoil contribution is treated within the framework of the rigorous QED approach to the first order in the electron-to-nucleus mass ratio m/M and to all orders in the parameter αZ. These calculations are performed in a range Z=3-92. The two-electron recoil term is calculated for low- and middle-Z ions within the Breit approximation using a four-component approach. The results for the two-electron recoil part obtained in the Letter strongly disagree with the previous calculations performed using an effective two-component Hamiltonian...
December 29, 2017: Physical Review Letters
D Céolin, N V Kryzhevoi, Ch Nicolas, W Pokapanich, S Choksakulporn, P Songsiriritthigul, T Saisopa, Y Rattanachai, Y Utsumi, J Palaudoux, G Öhrwall, J-P Rueff
X-ray photoelectron and KLL Auger spectra were measured for the K^{+} and Cl^{-} ions in aqueous KCl solution. While the XPS spectra of these ions have similar structures, both exhibiting only weak satellites near the main line, the Auger spectra differ dramatically. Contrary to the chloride case, a very strong extra peak was found in the Auger spectrum of K^{+} at the low kinetic energy side of the ^{1}D state. Using the equivalent core model and ab initio calculations this spectral feature was assigned to electron transfer processes from solvent water molecules to the solvated cation...
December 29, 2017: Physical Review Letters
Elizabeth K Coward, Tsutomu Ohno, Alain F Plante
Iron (Fe)-bearing mineral phases contribute disproportionately to adsorption of soil organic matter (SOM), due to their elevated chemical reactivity and specific surface area (SSA). However, the spectrum of Fe solid-phase speciation present in oxidation-reduction-active soils challenges analysis of SOM-mineral interactions and may induce differential molecular fractionation of dissolved organic matter (DOM). This work used paired selective dissolution experiments and batch sorption of post-extraction residues to 1) quantify the contributions of Fe-bearing minerals of varying crystallinity to DOM sorption, and 2) characterize molecular fractionation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS)...
January 12, 2018: Environmental Science & Technology
Aashutosh Mistry, Kandler Smith, Partha P Mukherjee
Lithium-ion battery electrodes exhibit complex interplay among multiple electrochemically coupled transport processes, which rely on the underlying functionality and relative arrangement of different constituent phases. The electrochemically inactive solid phases (e.g., conductive additive and binder, referred to as the secondary phase) while beneficial for improved electronic conductivity and mechanical integrity, may partially block the electrochemically active sites and introduce additional transport resistances in the pore (electrolyte) phase...
January 12, 2018: ACS Applied Materials & Interfaces
Davide Raffaele Ceratti, Yevgeny Rakita, Lorenzo Cremonesi, Ron Tenne, Vyacheslav Kalchenko, Michael Elbaum, Dan Oron, Marco Alberto Carlo Potenza, Gary Hodes, David Cahen
Self-healing, where a modification in some parameter is reversed with time without any external intervention, is one of the particularly interesting properties of halide perovskites. While there are a number of studies showing such self-healing in perovskites, they all are carried out on thin films, where the interface between the perovskite and another phase (including the ambient) is often a dominating and interfering factor in the process. Here, self-healing in perovskite (methylammonium, formamidinium, and cesium lead bromide (MAPbBr3 , FAPbBr3 , and CsPbBr3 )) single crystals is reported, using two-photon microscopy to create damage (photobleaching) ≈110 µm inside the crystals and to monitor the recovery of photoluminescence after the damage...
January 12, 2018: Advanced Materials
Liang Zhang, Dan Sun, Jun Kang, Jun Feng, Hans A Bechtel, Lin-Wang Wang, Elton J Cairns, Jinghua Guo
As a typical transition metal dichalcogenide, MoS2 offers numerous advantages for nanoelectronics and electrochemical energy storage due to its unique layered structure and tunable electronic properties. When used as the anode in lithium-ion cells, MoS2 undergoes intercalation and conversion reactions in sequence upon lithiation, and the reversibility of the conversion reaction is an important but still controversial topic. Here, we clarify unambiguously that the conversion reaction of MoS2 is not reversible and the formed Li2S is converted to sulfur in the first charge process...
January 12, 2018: Nano Letters
Kyra N Smit, Natasha M van Poppelen, Jolanda Vaarwater, Robert Verdijk, Ronald van Marion, Helen Kalirai, Sarah E Coupland, Sophie Thornton, Neil Farquhar, Hendrikus-Jan Dubbink, Dion Paridaens, Annelies de Klein, Emine Kiliç
Uveal melanoma is a highly aggressive cancer of the eye, in which nearly 50% of the patients die from metastasis. It is the most common type of primary eye cancer in adults. Chromosome and mutation status have been shown to correlate with the disease-free survival. Loss of chromosome 3 and inactivating mutations in BAP1, which is located on chromosome 3, are strongly associated with 'high-risk' tumors that metastasize early. Other genes often involved in uveal melanoma are SF3B1 and EIF1AX, which are found to be mutated in intermediate- and low-risk tumors, respectively...
January 12, 2018: Modern Pathology: An Official Journal of the United States and Canadian Academy of Pathology, Inc
Amit Khare, Jaekwang Lee, Jaeseoung Park, Gi-Yeop Kim, Si-Young Choi, Takayoshi Katase, Seulki Roh, Tae Sup Yoo, Jungseek Hwang, Hiromichi Ohta, Junwoo Son, Woo Seok Choi
Transition metal oxides with brownmillerite (BM) structures possess one-dimensional oxygen vacancy channels, which play a key role in realizing high ionic conduction at low temperatures. The controllability of the vacancy channel orientation, thus, possess a great potential for practical applications, and would provide a better visualization of the diffusion pathways of ions in transition metal oxides. In this study, the orientations of the oxygen vacancy channels in BM-SrFeO2.5 are stabilized along two crystallographic directions of the epitaxial thin films...
January 12, 2018: ACS Applied Materials & Interfaces
Lin Liu, Hua Zhang, Daqian Song, Zhenxin Wang
We report a new fluorescence resonance energy transfer (FRET) sensing platform for the sensitive detection of caspase-3 activity in vitro and in cells using NaGdF4:Yb3+,Er3+@NaGdF4 upconversion nanoparticles (UCNPs) as the energy donor and Rhodamine B (RB) as the energy acceptor. The phosphorylated RB-modified peptide containing a caspase-3 cleavage site and cell-penetrating peptide (CPP) motif (sequence, (RB)-DEVDGGS(p)GCGT(p)GRKKRRQRRRPQ) is immobilized on the UCNP surface via the strong coordination interaction between Gd3+ ions with phosphate...
January 12, 2018: Analyst
S A R Shahamirifard, M Ghaedi, M Montazerozohori, A Masoudiasl
In this work, the use of carbon dots (CDs) as a complexing agent and sensitizer in a polymeric matrix for determination of copper(ii) by UV-vis spectroscopy is reported for the first time. A new and highly selective Schiff base, namely, (N',N'''E,N',N'''E)-N',N'''-((((2-hydroxypropane-1,3-diyl)bis(oxy))bis(2,1-phenylene))bis(methan-ylylidene))di(isonicotinohydrazide) (NHBMDI), was also incorporated in the polymeric matrix. For the first time, the membrane composition of the proposed optical sensor including NHBMDI as the ionophore, tetraphenylborate (NaTPB) as the anionic additive, dibutyl phthalate (DBP) as the plasticizer and polyvinyl chloride (PVC) as the immobilizer was optimized through central composite design combined with the desirability function approach (DFA) because this method saves material and time consumption and is therefore cost effective...
January 12, 2018: Photochemical & Photobiological Sciences
Melek Cemre Manav, Jelena Beljantseva, Martin Saxtorph Bojer, Tanel Tenson, Hanne Ingmer, Vasili Hauryliuk, Ditlev Egeskov Brodersen
The stringent response is a global reprogramming of bacterial physiology that renders cells more tolerant to antibiotics and induces virulence gene expression in pathogens in response to stress. This process is driven by accumulation of the intracellular alarmone guanosine-5'-di(tri)phosphate-3'-diphosphate ([p]ppGpp), which is produced by enzymes of the RelA SpoT homologue (RSH) family. The Gram-positive Firmicute pathogen, Staphylococcus aureus, encodes three RSH enzymes: a multi-domain RSH (Rel) that senses amino acid starvation on the ribosome and two small alarmone synthetase (SAS) enzymes, RelQ (SAS1) and RelP (SAS2)...
January 11, 2018: Journal of Biological Chemistry
Arghya Majee, Markus Bier, Rudolf Podgornik
The interaction between two chemically identical charge-regulated surfaces is studied using the classical density functional theory. In contrast to common expectations and assumptions, under certain realistic conditions we find a spontaneous emergence of disparate charge densities on the two surfaces. The surface charge densities can differ not only in their magnitude, but quite unexpectedly, even in their sign, implying that the electrostatic interaction between the two chemically identical surfaces can be attractive instead of repulsive...
January 11, 2018: Soft Matter
Leilei Shi, Yufeng Liu, Qian Wang, Tiankuo Wang, Yubin Ding, Yi Cao, Zhe Li, Hui Wei
By combining leucine (Leu) and tetraphenylethene (TPE), a pH-sensitive aggregation induced emission (AIE) probe TPE-Leu was developed. The aliphatic amine in TPE-Leu was more easily protonated under acidic conditions, which made TPE-Leu more water soluble. Therefore, the protonated AIE probe showed weak fluorescence under acidic conditions. When the pH was changed to basic conditions, it showed strong fluorescence due to the hydrophobic nature of TPE-Leu. We demonstrated that the probe showed high selectivity toward pH changes with the coexistence of other potential species such as metal ions, redox agents, and biomolecules...
January 11, 2018: Analyst
Joao L Carvalho-de-Souza, Francisco Bezanilla
Voltage sensitivity in ion channels is a function of highly conserved arginine residues in their voltage-sensing domains (VSDs), but this conservation does not explain the diversity in voltage dependence among different K+ channels. Here we study the non-voltage-sensing residues 353 to 361 in Shaker K+ channels and find that residues 358 and 361 strongly modulate the voltage dependence of the channel. We mutate these two residues into all possible remaining amino acids (AAs) and obtain Q-V and G-V curves. We introduced the nonconducting W434F mutation to record sensing currents in all mutants except L361R, which requires K+ depletion because it is affected by W434F...
January 10, 2018: Journal of General Physiology
J A Kiernan
Previous investigators have disagreed about whether hemalum stains DNA or its associated nucleoproteins. I review here the literature and describe new experiments in an attempt to resolve the controversy. Hemalum solutions, which contain aluminum ions and hematein, are routinely used to stain nuclei. A solution containing 16 Al3+ ions for each hematein molecule, at pH 2.0-2.5, provides selective progressive staining of chromatin without cytoplasmic or extracellular "background color." Such solutions contain a red cationic dye-metal complex and an excess of Al3+ ions...
January 11, 2018: Biotechnic & Histochemistry: Official Publication of the Biological Stain Commission
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