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Ionic contrast

Roland Kjellander
Screened electrostatic interactions in ionic liquids are investigated by means of exact statistical mechanical analysis combined with physical arguments that enhance the transparency and conceptual accessibility of the analysis and results. The constituent ions and immersed particles in the liquid can have arbitrary shapes and any internal charge distributions. The decay of the screened electrostatic potential and the free energy of interaction in ionic liquids can be exponentially damped oscillatory (like in molten simple salts) as well as plain exponential and long-ranged (like in dilute electrolyte solutions)...
September 28, 2016: Journal of Chemical Physics
Simin Zhang, Yanmei Zheng, Shengyan Yin, Jingzhi Sun, Bao Li, Lixin Wu
In this study, a uniform complex dual micelle bearing gadolinium substituted polyoxometalate core, hydrophobic middle, and biocompatible organic shell, which exhibited a uniform size and definite molecular weight and chemical composition, was constructed for fluorescent and magnetic resonance imaging contrast agent, via a simple two-step preparation. A paramagnetic polyoxometalate cluster K13[Gd(β2-SiW11O39)2] was firstly encapsulated with a cationic dendron in 3-generation (D-3) bearing triethylene glycol monomethyl ether terminal groups through ionic substitution...
October 24, 2016: Chemistry: a European Journal
Gil Henkin, Daniel Berard, Francis Stabile, Marjan Shayegan, Jason S Leith, Sabrina R Leslie
We present a dynamically adjustable nanofluidic platform for formatting the conformations of and visualizing the interaction kinetics between biomolecules in solution, offering new time resolution and control of the reaction processes. This platform extends Convex Lens-induced Confinement (CLiC), a technique for imaging molecules under confinement, by introducing a system for in-situ modification of the chemical environment; this system uses a deep microchannel to diffusively exchange reagents within the nanoscale imaging region, whose height is fixed by a nanopost array...
October 21, 2016: Analytical Chemistry
Astha Garg, Charles A Cartier, Kyle J M Bishop, Darrell Velegol
The zeta potential of a particle characterizes its motion in an electric field and is often thought to be negligible at high ionic strength (several moles per liter) due to thinning of the electrical double layer (EDL). Here, we describe zeta potential measurements on polystyrene latex (PSL) particles at monovalent salt concentrations up to saturation (~ 5 M NaCl) using electrophoresis in sinusoidal electric fields and high-speed video microscopy. Our measurements reveal that the zeta potential remains finite at even the highest concentrations...
October 21, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Joseph S Hudson, Kingsley Abode-Iyamah, Yasunori Nagahama, Chandan G Reddy
BACKGROUND: Ionic contrast, if accidentally injected into the intrathecal space during routine imaging studies or interventional procedures, may significantly interfere with neuronal activity, potentially causing ascending tonic-clonic seizure syndrome and even death. As a result, ionic contrast is strictly contraindicated for intrathecal use. Rapid recognition of the condition followed by prompt management, typically involving aggressive cerebrospinal fluid (CSF) drainage, is critical to improving patient outcome...
October 17, 2016: World Neurosurgery
Heni Rachmawati, Annisa Rahma, Loaye Al Shaal, Rainer H Müller, Cornelia M Keck
We have successfully developed curcumin nanosuspension intended for oral delivery. The main purpose is to improve bioavailability through enhancing its solubility. The nanoparticles were stabilized using various stabilizers, including polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), sodium carboxymethylcellulose (Na-CMC), d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), and sodium dodecyl sulfate (SDS). The average diameter of particles, microscopic appearance, and sedimentation of each preparation was observed and compared...
October 18, 2016: Scientia Pharmaceutica
Mordjane Boukhet, Fabien Piguet, Hadjer Ouldali, Manuela Pastoriza-Gallego, Juan Pelta, Abdelghani Oukhaled
The transport of macromolecules through nanopores is involved in many biological functions and is today at the basis of promising technological applications. Nevertheless the interpretation of the dynamics of the macromolecule/nanopore interaction is still misunderstood and under debate. At the nanoscale, inside biomimetic channels under an external applied voltage, electrophoresis, which is the electric force acting on electrically charged molecules, and electroosmotic flow (EOF), which is the fluid transport associated with ions, contribute to the direction and magnitude of the molecular transport...
October 20, 2016: Nanoscale
Ali Yusuf Öner, Berrak Barutcu, Şükrü Aykol, Emin Turgut Tali
OBJECTIVES: There have been recent studies evaluating brain magnetic resonance imaging changes in patients with normal renal function, after intravenous administration of gadolinium-based contrast agents (GBCAs). Their findings were supported by histological evidence as well and brought a new vision concerning what needs to be learned to provide better patient care. In this report, we aim to present brain magnetic resonance imaging changes after intrathecal administration of a linear ionic agent (gadopentetate dimeglumine)...
October 13, 2016: Investigative Radiology
Pavel Hanč, Oliver Schulz, Hanna Fischbach, Stephen R Martin, Svend Kjær, Caetano Reis E Sousa
DNGR-1 is receptor expressed by certain dendritic cell (DC) subsets and by DC precursors in mouse. It possesses a C-type lectin-like domain (CTLD) followed by a poorly characterized neck region coupled to a transmembrane region and short intracellular tail. The CTLD of DNGR-1 binds F-actin exposed by dead cell corpses and causes the receptor to signal and potentiate cross-presentation of dead cell-associated antigens by DCs. Here, we describe a conformational change that occurs in the neck region of DNGR-1 in a pH- and ionic strength-dependent manner and that controls cross-presentation of dead cell-associated antigens...
October 17, 2016: EMBO Journal
James R Costello, Bobby Kalb, Diego R Martin
Since their clinical introduction in 1988, gadolinium-based contrast agents (GBCAs) have demonstrated an excellent safety profile with a reported acute adverse reaction rate ranging from 0.01% to 2%. By comparison, the acute adverse reaction rate of low osmolar nonionic computed tomography contrast agents (CTCs) ranges from 0.7% to 3.1%. Many of the risk factors associated with CTC reactions (drug allergies, asthma, atopy, prior contrast reaction) also point toward an increased incidence of acute adverse events to GBCAs...
June 29, 2016: Topics in Magnetic Resonance Imaging: TMRI
Veronika Metlenko, WooChul Jung, Sean R Bishop, Harry L Tuller, Roger A De Souza
Oxygen transport in the mixed ionic-electronic conducting perovskite-oxides SrTi1-yFeyO3-δ (with y = 0.5 and y = 1.0) was studied by oxygen isotope exchange measurements. Experiments were performed on thin-film samples that were grown by Pulsed Laser Deposition (PLD) on MgO substrates. Isotope penetration profiles were introduced by (18)O2/(16)O2 exchanges into the plane of the films at various temperatures in the range 773 < T/K < 973 at an oxygen activity aO2 = 0.5. Isotope profiles were determined subsequently by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and their analysis yielded tracer diffusion coefficients D* and oxygen surface exchange coefficients k*...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Jia Feng, Shengli Shi, Liangyu Pei, Junping Lv, Qi Liu, Shulian Xie
Phenol components are major industry contaminants of aquatic environment. Among all practical methods for removing phenol substances from polluted water, activated carbon absorption is the most effective way. Here, we have produced low-cost activated carbon using Polygonum orientale Linn, a wide spreading species with large biomass. The phenol adsorption ability of this activated carbon was evaluated at different physico-chemical conditions. Average equilibrium time for adsorption was 120 min. The phenol adsorption ability of the P...
2016: PloS One
Chiara Ferrara, Christopher Eames, M Saiful Islam, Cristina Tealdi
Lattice strain is considered a promising approach to modulate the structural and functional properties of oxide materials. In this study we investigate the effect of lattice strain on doping, hydration and proton transport for the family of scheelite-type proton conductors using both atomistic and DFT computational methods. The results suggest that tensile strain improves the dopant solubility and proton uptake of the material. The anisotropic proton pathways change from being within the a-b plane to being in the a-c plane...
October 13, 2016: Physical Chemistry Chemical Physics: PCCP
Katsuhiko Yamamoto, Taro Kojima, Masatoshi Karashima, Yukihiro Ikeda
To judge the developability and analyze functional mechanism of co-amorphouses, we investigated the physicochemical properties of co-amorphouses and compare the properties with the co-crystals having the same drug and counters. Co-amorphous compounds are a novel approach to improve the physicochemical properties of drugs. A co-amorphous is in an amorphous solid state allowing non-ionic interactions between drug molecules and counter molecules. The co-amorphous compounds composed of itraconazole (ITZ) with the organic carboxyl acid, fumaric acid (FA) or L-tartaric acid (TA), were prepared by mechanical grinding...
October 12, 2016: Chemical & Pharmaceutical Bulletin
Sophia Sakellariou, Wenguang Li, Manosh C Paul, Giles Roditi
Iodinated contrast media (CM) are the most commonly used injectables in radiology today. A range of different media are commercially available, combining various physical and chemical characteristics (ionic state, osmolality, viscosity) and thus exhibiting distinct in vivo behaviour and safety profiles. In this paper, numerical simulations of blood flow with contrast media were conducted to investigate the effects of contrast viscosity on generated vessel wall shear stress and vessel wall pressure to elucidate any possible relation to extravasations...
October 8, 2016: Medical Engineering & Physics
Alireza Chackoshian Khorasani, Seyed Abbas Shojaosadati
Incorporation of nanofibers of chitin (NC), lignocellulose (NLC) and bacterial cellulose (BNC) in pectin was studied to improve prebiotic activity and gastrointestinal resistance of the pectin-nanofibers biocomposites for protection of probiotics under simulated gastrointestinal conditions. The biocomposites were prepared using various compositions of pectin and nanofibers, which were designed using D-optimal mixture method. The incorporation of the nanofibers in pectin led to a slow degradation of the pectin-nanofibers biocomposites in contrast to their rapid swelling...
October 6, 2016: International Journal of Biological Macromolecules
Yu Su, Guoqing Yang, Kun Lu, Elijah J Petersen, Liang Mao
Understanding the colloidal stability of graphene is essential for predicting its transport and ecological risks in aquatic environments. We investigated the agglomeration of (14)C-labeled few-layer graphene (FLG) at concentrations spanning nearly four orders of magnitude (2 μg/L to 10 mg/L) using dynamic light scattering and sedimentation measurements. FLG agglomerates formed rapidly in deionized water at concentrations >3 mg/L. From 1 mg/L to 3 mg/L, salt-induced agglomeration was decreased with dilution of FLG suspensions; the critical coagulation concentration of the more concentrated suspension (3 mg/L) was significantly lower than the dilute suspension (1 mg/L) in the presence of NaCl (1...
October 6, 2016: Environmental Pollution
Eduardo Guzmán, Francisco Ortega, Ramón G Rubio
Tang and Besseling recently published a study on the growth of polyelectrolyte multilayers formed by poly(diallyl-dimethylammonium chloride), PDADMAC, and the sodium salt of poly(4-styrenesulfonate), PSSNa. They described the different growth regimes appearing in the (PDADMAC + PSS)n multilayers within a scenario in which the appearance of interdiffusion of the polyelectrolyte chains within the multilayer architecture plays a central role in the transition between the different regimes. However, this account contrasts, without an apparent explanation, with previous experimental evidence reported in the literature...
October 3, 2016: Soft Matter
Christian Burger, Nora G Kling, Robert Siemering, Ali S Alnaser, Boris Bergues, Abdallah M Azzeer, Robert Moshammer, Regina de Vivie-Riedle, Matthias Kübel, Matthias F Kling
The migration of hydrogen atoms resulting in the isomerization of hydrocarbons is an important process which can occur on ultrafast timescales. Here, we visualize the light-induced hydrogen migration of acetylene to vinylidene in an ionic state using two synchronized 4 fs intense laser pulses. The first pulse induces hydrogen migration, and the second is used for monitoring transient structural changes via Coulomb explosion imaging. Varying the time delay between the pulses reveals the migration dynamics with a time constant of 54 ± 4 fs as observed in the H(+) + H(+) + CC(+) channel...
September 15, 2016: Faraday Discussions
H Koch, K Noack, S Will
Raman spectroscopy is a very sensitive and specific measurement tool for probing intermolecular interaction structures. As imidazolium-based ionic liquids can favorably be used for enantioseparation, in this work two approaches for Raman signal analysis, namely by means of excess spectra and principal component analysis (PCA), are compared to extract detailed information about the interaction structure of the enantiomers d- and l-glucose in an aqueous solution of the ionic liquid [EMIM][EtSO4]. In contrast to the excess calculations, the loadings obtained from PCA lead to significant results since the interactions are weighted by their strength and significance...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
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