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Ionic contrast

Kai-Uwe Goss, Kai Bittermann, Luise Henneberger, Lukas Linden
In this work we combine partition coefficients between water and membrane lipid, storage lipid, the plasma protein albumin as well as structural protein with the tissue dependent fraction of the respective phases in order to obtain a clearer picture on the relevance of various biological tissues for the bioaccumulation of 31 organic anions. Most of the partition coefficients are based on experimental data, supplemented by some predicted ones. The data suggest that the plasma protein, albumin, will be the major sorption matrix in mammals...
February 6, 2018: Chemosphere
Alyson R Ribeiro, Holger V Lutze, Torsten C Schmidt
Lately, special attention has been given to veterinary cephalosporin antibiotics due to their broad activity spectrum and significant consumption. Indeed, the determination of hydrolytic and photolytic kinetics provides a better comprehension of the undesired persistence of cephalosporins in aqueous matrices. In this work, the two widely used veterinary antibiotics ceftiofur (CEF) and cefapirin (CEPA) showed high instability under alkaline conditions, degrading in few minutes at pH > 11. In buffered solutions at neutral pH and natural temperature (T = 22 ± 1 °C), both drugs presented moderate stability (t½ = 3 d, CEPA and 1...
December 22, 2017: Water Research
Jinn-Liang Liu, Bob Eisenberg
The combinatorial explosion of empirical parameters in tens of thousands presents a tremendous challenge for extended Debye-Hückel models to calculate activity coefficients of aqueous mixtures of the most important salts in chemistry. The explosion of parameters originates from the phenomenological extension of the Debye-Hückel theory that does not take steric and correlation effects of ions and water into account. By contrast, the Poisson-Fermi theory developed in recent years treats ions and water molecules as nonuniform hard spheres of any size with interstitial voids and includes ion-water and ion-ion correlations...
February 7, 2018: Journal of Chemical Physics
Artemy D Beniaminov, Lyubov G Dezhenkova, Olga K Mamaeva, Anna K Shchyolkina, Anna N Tevyashova, Dmitry N Kaluzhny, Alexander A Shtil
The current model of binding of the antitumor antibiotic olivomycin A (1) to GC-rich DNA regions presumes that coordination of the magnesium divalent cation with drug dimers is necessary for binding of 1 into the minor groove of the DNA duplex. Previously we have synthesized the derivatives of 1 termed 'short acid' (2) and its N,N-dimethylaminoethylamide (3). The latter compound demonstrated an improved tolerance in vivo compared to 1 and good therapeutic potency in animal models. We herein report that compound 3 is able to form stable complexes with DNA in the absence of Mg2+, in striking contrast to 1 whose binding to the DNA absolutely requires Mg2+...
2018: PloS One
Anne Strate, Viviane Overbeck, Viktoria Lehde, Jan Neumann, Anne-Marie Bonsa, Thomas Niemann, Dietmar Paschek, Dirk Michalik, Ralf Ludwig
Ion pairing is one of the most fundamental atomic interactions in chemistry and biology. In contrast, pairing between like-charged ions remains an elusive concept. So far, this phenomenon was observed only for large-scaled structures, assemblies, stabilizing frameworks, or in aqueous solution wherein like-charge attraction is supported by mediating water molecules. Recently, we reported the formation of cationic clusters in pure ionic liquids (ILs) which all include hydroxyl groups (OH) for possible hydrogen bonding...
February 7, 2018: Physical Chemistry Chemical Physics: PCCP
Calvin J Young, Kaitlin Richard, Ananya Beruar, Suet Y Lo, Stefan Siemann
Anthrax lethal factor (LF) is a zinc-dependent endopeptidase involved in the cleavage of proteins critical to the maintenance of host signaling pathways during anthrax infections. Although zinc is typically regarded as the native metal ion in vivo, LF is highly tolerant to metal substitution, with its replacement by copper yielding an enzyme (CuLF) 4.5-fold more active than the native zinc protein (at pH 7). The current study demonstrates that by careful choice of the buffer, ionic strength, pH and substrate, the activity ratio of CuLF and native LF can be increased to >40-fold...
February 1, 2018: Journal of Inorganic Biochemistry
Shuhei Shinohara, Namsoon Eom, E-Jen Teh, Kaoru Tamada, Drew Francis Parsons, Vincent S J Craig
The interactions between colloidal particles and nanoparticles determines solution stability and the structures formed when the particles are unstable to flocculation. Therefore knowledge of the inter-particle interactions is important for understanding the transport, dissolution and fate of particles in the environment. The interactions between particles are governed by the surface properties of the particles, which are altered when species adsorb to the surface. The important interactions in the environment are almost never those between the bare particles but rather those between particles that have been modified by the adsorption of natural organic materials...
February 6, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Lea L Sorret, Madison A DeWinter, Daniel K Schwartz, Theodore W Randolph
We investigated the effects of protein-protein interaction strength on interfacial viscoelastic properties and aggregation of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) at silicone oil-water interfaces. Osmotic second virial coefficients determined by static light scattering were used to quantify protein-protein interactions in bulk solution. Attractive protein-protein interactions dominated at low ionic strengths and their magnitude decreased with increasing ionic strength, in contrast to repulsive interactions that would be expected based on uniformly charged sphere models...
February 1, 2018: Protein Science: a Publication of the Protein Society
Arunkumar Pitchaimani, Tuyen Duong, Thanh Nguyen, Leila Maurmann, Jaehong Key, Stefan H Bossmann, Santosh Aryal
Near infrared (NIR) mediated photothermal therapy and magnetic resonance imaging (MRI) are promising treatment and imaging modalities in the field of cancer theranostics. Gold nanorods are the first choice of materials for NIR-mediated photothermal therapy due to their strong localized surface plasmon resonance (LSPR) at NIR region. Similarly, gadolinium based MRI contrast agents have an ability to increase the ionic and molecular relaxivity, thereby enhancing the solvent proton relaxation rate resulting in contrast enhancement...
April 2017: Journal of Biomedical Nanotechnology
Amrita Sikder, Jayita Sarkar, Tsuneaki Sakurai, Shu Seki, Suhrit Ghosh
This manuscript reports solvent tunable functional nano-assemblies of an unsymmetrical bola-shaped π-amphiphile (NDI-PY) which consists of a hydrophobic naphthalene-diimide (NDI) chromophore connected to a non-ionic hydrophilic wedge and a pyridine group at its two opposite arms. Importantly, it contains a hydrazide group located at the hydrophobic domain between the NDI-chromophore and the hydrophilic-wedge to drive the supramolecular assembly by directional H-bonding. NDI-PY exhibits spontaneous assembly in water as well as in a highly non-polar solvent like tetra-chloroethylene (TCE) by the synergistic effect of H-bonding and π-stacking interaction...
January 31, 2018: Nanoscale
Jun Rao, R Vijayaraghavan, Yundong Zhou, Patrick C Howlett, Douglas R MacFarlane, Maria Forsyth, Haijin Zhu
Proton conductors are widely used in different electrochemical devices including fuel cells and redox flow batteries. Compared to conventional proton conducting polymer membranes, protic organic ionic plastic crystal (POIPC) is a novel solid-state proton conductor with high proton conductivity even under anhydrous conditions. In this work, different organic protic salts based on the same parent di-functional cation with different anions were synthesized and characterized. It is found that the di-protonated cation plays an important role in defining the thermal properties, leading to stronger plastic crystal behavior and a higher melting point...
January 29, 2018: Physical Chemistry Chemical Physics: PCCP
Huixin Wang, Cheng Hao Wu, Robert S Weatherup, Bingmei Feng, Yifan Ye, Yi-Sheng Liu, Per-Anders Glans, Jinghua Guo, Hai-Tao Fang, Miquel B Salmeron
We investigated the x-ray absorption spectroscopy (XAS) fingerprint of EMImTFSI ionic liquid (IL) and its fragmentation products created by x-ray irradiation. To accomplish this, we used an open geometry where an IL droplet is directly exposed in the vacuum chamber, and an enclosed geometry where the IL is confined in a cell covered by an x-ray transparent membrane. In the open geometry, the XAS signature was stable and consistent with experimental and theoretical spectra reported in the literature. In contrast, when the IL is enclosed, its XAS evolved continuously under x-ray illumination due to accumulation of volatile fragmentation products inside the closed cell, while they evaporate in the open geometry...
January 27, 2018: Journal of Physical Chemistry Letters
Daniele Pantano, Nicole Neubauer, Jana Navratilova, Lorette Scifo, Chiara Civardi, Vicki Stone, Frank von der Kammer, Philipp Müller, Marcos Sanles Sobrido, Bernard Angeletti, Jerome Rose, Wendel Wohlleben
Here we compare the standard European benchmark of wood treatment by molecularly dissolved copper amine (Cu-amine), also referred to as aqueous copper amine (ACA), against two nanoenabled formulations: copper(II)oxide nanoparticles (CuO NPs) in an acrylic paint to concentrate Cu as a barrier on the wood surface, and a suspension of micronized basic copper carbonate (CuCO3·Cu(OH)2) for wood pressure treatment. After characterizing the properties of the (nano)materials and their formulations, we assessed their effects in vitro against three fungal species: Coniophora puteana, Gloeophyllum trabeum, and Trametes versicolor, finding them to be mediated only partially by ionic transformation...
January 26, 2018: Environmental Science & Technology
Paul S Bagus, Connie J Nelin, Michel Sassi, Eugene S Ilton, Kevin M Rosso
Cluster models of condensed systems are often used to simulate the core-level spectra obtained with X-ray Photoelectron Spectroscopy, XPS, or with X-ray Absorption Spectroscopy, XAS, especially for near edge features. The main objective of this paper is to examine the dependence of the predicted L2,3 edge XAS of α-Fe2O3, an example of a high spin ionic crystal, on increasingly realistic models of the condensed system. It is shown that an FeO6 cluster model possessing the appropriate local site symmetry describes most features of the XAS and is a major improvement over the isolated Fe3+ cation...
January 26, 2018: Physical Chemistry Chemical Physics: PCCP
Aarne Vartia
BACKGROUND: Kt/V urea reflects the efficacy of haemodialysis scaled to patient size (urea distribution volume). The guidelines recommend monthly Kt/V measurements based on blood samples. Modern haemodialysis machines are equipped with accessories monitoring the dose online at every session without extra costs, blood samples and computers. OBJECTIVE: To describe the principles, devices, benefits and shortcomings of online monitoring of haemodialysis dose. DESIGN: A critical literature overview and discussion...
January 25, 2018: Journal of Renal Care
Muhammad Azeemuddin, Mustafa Belal Hafeez Chaudhry, Jehanzeb Shahid, Sarosh Zafar Belal
61-years-old male patient presented with complain of neck swelling and soreness following contrast-enhanced (CE) CT examination with resolution of symptoms in 36-48 hours. He is diagnosed with hepatitis C virus and hepatocellular carcinoma (HCC); already treated with radiofrequency ablation for HCC. He had already undergone two CECT examinations before he was referred to our institution for disease staging/treatment. He also underwent three triphasic CT scan examinations at our institution during the course of treatment for treatment response and staging...
January 23, 2018: BMJ Case Reports
Zhengxiang Liu, Jianfeng Zhu, Xiuyan Yang, Haiwen Wu, Qi Wei, Hairong Wei, Huaxin Zhang
Elaeagnus angustifolia is one of the most extensively afforested tree species in environment-harsh regions of northern China. Despite its exceptional tolerance to saline soil, the intrinsic adaptive physiology has not been revealed. In this study, we investigated the growth, organ-level ionic relations and organic osmoregulation of the seedlings hydroponically treated with 0, 100 and 200 mM NaCl for 30 days. We found that the growth characteristics and the whole-plant dry weight were not obviously stunted, but instead, were even slightly stimulated by the treatment of 100 mM NaCl...
2018: PloS One
Mário B G Nunes, Antônio C Filho, Valéria R C Alvares, Rafael Moreno, Edgar Lamas, Vitor Loures, Daniel Chamié, Alexandre Abizaid
INTRODUCTION: Individuals with glomerular filtration rate (GFR) ≥60 ml/min/1.73 m2 estimated by the Cockcroft-Gault formula (CG) who undergo percutaneous coronary intervention (PCI) frequently develop contrast-induced nephropathy (CIN). This study aimed to assess whether individuals with significant renal impairment assessed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, but not by CG, more often develop CIN following PCI than those without renal impairment by either formula...
January 15, 2018: Portuguese Journal of Cardiology: An Official Journal of the Portuguese Society of Cardiology
Keisuke Ueda, Harunobu Kanaya, Kenjirou Higashi, Keiji Yamamoto, Kunikazu Moribe
In this work, the effect of saccharin (SAC) addition on the dissolution and supersaturation level of phenytoin (PHT)/Eudragit® E (EUD-E) solid dispersion (SD) at neutral pH was examined. The PHT/EUD-E SD showed a much slower dissolution of PHT compared to the PHT/EUD-E/SAC SD. EUD-E formed a gel layer after the dispersion of the PHT/EUD-E SD into an aqueous medium, resulting in a slow dissolution of PHT. Pre-dissolving SAC in the aqueous medium significantly improved the dissolution of the PHT/EUD-E SD. Solid-state 13C NMR measurements showed an ionic interaction between the tertiary amino group of EUD-E and the amide group of SAC in the EUD-E gel layer...
January 13, 2018: International Journal of Pharmaceutics
Sin-Yi Liou, Wan-Ru Chen
Albendazole (ABZ) is a benzimidazole-based veterinary anthelmintic used extensively in the treatment of intestinal parasites. Due to its high hydrophobicity, ABZ tends to accumulate in soils and sediments in the environment. This study aims to investigate ABZ's possible degradation by manganese oxides. Minor effects from ionic strength and metal cations on ABZ degradation were observed. By contrast, decrease of pH greatly enhanced the reaction rate. Surface complexation between ABZ and MnO2 was indicated to be the dominant control in the reaction kinetics...
December 29, 2017: Journal of Hazardous Materials
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