Cation-Cation, Cation-Anion, and Anion-Anion Translation Diffusion in Ionic Liquids─Insight from NMR Relaxometry.

H and F spin-lattice relaxation experiments have been performed for a series of ionic liquids: [HMIM][TFSI], [OMIM][TFSI], and [DMIM][TFSI] including the same anion and cations with progressively longer alkyl chains. The experiments were performed in a wide frequency range from 10 kHz to 10 MHz (referring to the H resonance frequency) versus temperature. This extensive data set has been analyzed in terms of a theoretical model including all relevant homonuclear (H-H and F-F) and heteronuclear (H-F) relaxation pathways and linking the relaxation features to the relative translational diffusion between the ion pairs (cation-cation, cation-anion, and anion-anion).

Dynamics of ionic liquid-polymer gel membranes-Insight from NMR relaxometry for [BMIM][BF4]-PVDF-HFP systems.

1H spin-lattice relaxation experiments have been performed for ionic liquid-polymer gel membranes, including 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with different proportions. The experiments have been performed in a broad range of resonance frequencies (from about 5 Hz to 40 MHz) vs temperature and complemented with analogous studies for [BMIM][BF4] in bulk as a reference. A model of the relaxation processes in the membranes has been proposed.

Dynamics of ionic liquids by means of nuclear magnetic resonance relaxation - overview of theoretical approaches.

This paper presents a comprehensive overview of the spin relaxation theory needed for exploring nuclear magnetic resonance (NMR) relaxometry to study the dynamical properties of ionic liquids. The term NMR relaxometry refers to relaxation experiments performed over a wide range of magnetic fields (resonance frequencies). In this way, dynamical processes occurring on timescales from milliseconds to nanoseconds can be studied, including translational and rotational dynamics of both types of ions (cations and anions).

Markers of low field NMR relaxation features of tissues.

This work presents an approach to exploiting Nuclear Magnetic Resonance (NMR) relaxometry data (H spin-lattice relaxation rates covering the frequency range from below 1 kHz to 10 MHz) for the purpose of differentiating between pathological and reference tissues. Characteristic quantities (markers) that can be obtained in a straightforward manner, not resorting to an advanced analysis of H spin-lattice relaxation data, have been identified and compared for pathological and reference colon tissues. Moreover, the relaxation data have been parametrised in terms of Lorentzian spectral densities and the possibility of using the obtained dipolar relaxation constants and correlation times as biomarkers to assess the state of tissues has been discussed.

Dynamical properties of solid and hydrated collagen: Insight from nuclear magnetic resonance relaxometry.

1H spin-lattice Nuclear Magnetic Resonance relaxometry experiments have been performed for collagen and collagen-based artificial tissues in the frequency range of 10 kHz-20 MHz. The studies were performed for non-hydrated and hydrated materials. The relaxation data have been interpreted as including relaxation contributions originating from 1H-1H and 1H-14N dipole-dipole interactions, the latter leading to Quadrupole Relaxation Enhancement effects.

Dynamic of binary molecular systems-Advantages and limitations of NMR relaxometry.

1H spin-lattice relaxation studies have been performed for binary systems, including glycerol as the first component and alanine, glycine, and aspartic acid (with different levels of deuteration) as the second one. The relaxation studies have been performed in the frequency range from 10 kHz to 10 MHz vs temperature. A theoretical framework, including all relevant 1H-1H and 1H-2H relaxation pathways, has been formulated.

Diffusion of Water Molecules on the Surface of Silica Nanoparticles─Insights from Nuclear Magnetic Resonance Relaxometry.

H spin-lattice nuclear magnetic resonance (NMR) relaxation experiments have been performed for water dispersions of functionalized silica nanoparticles of diameters of 25 and 45 nm. The experiments have been performed in a broad frequency range spanning 3 orders of magnitude, from 10 kHz to 10 MHz, versus temperature, from 313 to 263 K. On the basis of the data, two-dimensional translation diffusion (diffusion close to the nanoparticle surface within a layer of the order of a few diameters of water molecules) has been revealed.

Water Dynamics in Highly Concentrated Protein Systems-Insight from Nuclear Magnetic Resonance Relaxometry.

H spin-lattice relaxation experiments have been performed for water-Bovine Serum Albumin (BSA) mixtures, including 20%wt and 40%wt of BSA. The experiments have been carried out in a frequency range encompassing three orders of magnitude, from 10 kHz to 10 MHz, versus temperature. The relaxation data have been thoroughly analyzed in terms of several relaxation models with the purpose of revealing the mechanisms of water motion.

Relative Cation-Anion Diffusion in Alkyltriethylammonium-Based Ionic Liquids.

F Nuclear Magnetic Resonance spin-lattice relaxation experiments have been performed for a series of ionic liquids including the same anion, bis(trifluoromethanesulfonyl)imide, and cations with alkyl chains of different lengths: triethylhexylammonium, triethyloctylammonium decyltriethylammonium, dodecyltriethylammonium, decyltriethylammonium, and hexadecyltriethylammonium. The experiments have been carried out in a frequency range of 10 kHz to 10 MHz versus temperature. A thorough analysis of the relaxation data has led to the determination of the cation-anion as a relative translation diffusion coefficient.

Relationship between Translational and Rotational Dynamics of Alkyltriethylammonium-Based Ionic Liquids.

H spin-lattice relaxation experiments have been performed for a series of ionic liquids including bis(trifluoromethanesulfonyl)imide anion and cations of a varying alkyl chain length: triethylhexylammonium, triethyloctylammonium, decyltriethylammonium, dodecyltriethylammonium, triethyltetradecylammonium, and hexadecyltriethylammonium. The relaxation studies were carried out in abroad frequency range covering three orders of magnitude, from 10 kHz to 10 MHz, versus temperature. On the basis of a thorough, quantitative analysis of this reach data set, parameters characterizing the relative, cation-cation, translation diffusion (relative diffusion coefficients and translational correlation times), and rotational motion of the cation (rotational correlation times) were determined.

Correlated Dynamics in Ionic Liquids by Means of NMR Relaxometry: Butyltriethylammonium bis(Trifluoromethanesulfonyl)imide as an Example.

H and F spin-lattice relaxation experiments have been performed for butyltriethylammonium bis(trifluoromethanesulfonyl)imide in the temperature range from 258 to 298 K and the frequency range from 10 kHz to 10 MHz. The results have thoroughly been analysed in terms of a relaxation model taking into account relaxation pathways associated with H-H, F-F and H-F dipole-dipole interactions, rendering relative translational diffusion coefficients for the pairs of ions: cation-cation, anion-anion and cation-anion, as well as the rotational correlation time of the cation. The relevance of the H-F relaxation contribution to the H and F relaxation has been demonstrated.

Towards applying NMR relaxometry as a diagnostic tool for bone and soft tissue sarcomas: a pilot study.

This work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients. We present the results of an ex vivo pilot study involving 10 cases of biopsy-proven sarcoma and we propose a quantitative method to analyse H NMR relaxation dispersion profiles based on a model-free approach describing the main dynamical processes in the tissues and assessing the amplitude of the Quadrupole Relaxation Enhancement effects due to N. This approach showed five distinct groups of dispersion profiles indicating five discrete categories of sarcoma, with differences attributable to microstructure and rigidity.

Slow dynamics of solid proteins - Nuclear magnetic resonance relaxometry versus dielectric spectroscopy.

H Nuclear Magnetic Resonance (NMR) relaxometry and Dielectric Spectroscopy (DS) have been exploited to investigate the dynamics of solid proteins. The experiments have been carried out in the frequency range of about 10 kHz-40 MHz for NMR relaxometry and 10Hz-20 MHz for DS. The data sets have been analyzed in terms of theoretical models allowing for a comparison of the correlation times revealed by NMR relaxometry and DS.

Dynamics of Solid Proteins by Means of Nuclear Magnetic Resonance Relaxometry.

H Nuclear magnetic resonance (NMR) relaxometry was exploited to investigate the dynamics of solid proteins. The relaxation experiments were performed at 37 °C over a broad frequency range, from approximately 10 kHz to 40 MHz. Two relaxation contributions to the overall H spin-lattice relaxation were revealed; they were associated with H-H and H-N magnetic dipole-dipole interactions, respectively.

Mechanism of Water Dynamics in Hyaluronic Dermal Fillers Revealed by Nuclear Magnetic Resonance Relaxometry.

H spin-lattice nuclear magnetic resonance relaxation experiments were performed for five kinds of dermal fillers based on hyaluronic acid. The relaxation data were collected over a broad frequency range between 4 kHz and 40 MHz, at body temperature. Thanks to the frequency range encompassing four orders of magnitude, the dynamics of water confined in the polymeric matrix was revealed.

Multi-quantum quadrupole relaxation enhancement effects in Bi compounds.

H spin-lattice nuclear magnetic resonance relaxation experiments have been performed for triphenylbismuth dichloride (CHBiCl) and phenylbismuth dichloride (CHBiCl) in powder. The frequency range of 20-128 MHz has been covered. Due to H-Bi dipole-dipole interactions, a rich set of pronounced Quadrupole Relaxation Enhancement (QRE) peaks (quadrupole peaks) has been observed.

Estimation of the magnitude of quadrupole relaxation enhancement in the context of magnetic resonance imaging contrast.

Magnetic Resonance Imaging (MRI) is one of the most powerful diagnostic tools providing maps of H relaxation times of human bodies. The method needs, however, a contrast mechanism to enlarge the difference in the relaxation times between healthy and pathological tissues. In this work, we discuss the potential of a novel contrast mechanism for MRI based on Quadrupole Relaxation Enhancement (QRE) and estimate the achievable value of QRE under the most favorable conditions.

Model - free approach to quadrupole spin relaxation in solid Bi-aryl compounds.

Nuclear Quadrupole Resonance (NQR) experiments were performed for deuterated and non-deuterated triphenylbismuth (BiPh3) to inquire into 209Bi relaxation mechanisms. The studies are motivated by the idea of exploiting Quadrupole Relaxation Enhancement (QRE) as a novel contrast mechanism for Magnetic Resonance Imaging. From this perspective relaxation features of nuclei possessing quadrupole moment (quadrupole nuclei) are of primary importance for the contrast effect.

Bi quadrupole relaxation enhancement in solids as a step towards new contrast mechanisms in magnetic resonance imaging.

Motivated by the possibility of exploiting species containing high spin quantum number nuclei (referred to as quadrupole nuclei) as novel contrast agents for Magnetic Resonance Imaging, based on Quadrupole Relaxation Enhancement (QRE) effects, 1H spin-lattice relaxation has been investigated for tris(2-methoxyphenyl)bismuthane and tris(2,6-dimethoxyphenyl)bismuthane in powder. The relaxation experiment has been performed in the magnetic field range of 0.5 T to 3 T (the upper limit corresponds to the field used in many medical scanners).

Thermodynamic consequences of the kinetic nature of the glass transition.

In this paper, we consider the glass transition as a kinetic process and establish one universal equation for the pressure coefficient of the glass transition temperature, dTg/dp, which is a thermodynamic characteristic of this process. Our findings challenge the common previous expectations concerning key characteristics of the transformation from the liquid to the glassy state, because it suggests that without employing an additional condition, met in the glass transition, derivation of the two independent equations for dTg/dp is not possible. Hence, the relation among the thermodynamic coefficients, which could be equivalent to the well-known Prigogine-Defay ratio for the process under consideration, cannot be obtained.

Adam-Gibbs model in the density scaling regime and its implications for the configurational entropy scaling.

To solve a long-standing problem of condensed matter physics with determining a proper description of the thermodynamic evolution of the time scale of molecular dynamics near the glass transition, we have extended the well-known Adam-Gibbs model to describe the temperature-volume dependence of structural relaxation times, τα(T, V). We also employ the thermodynamic scaling idea reflected in the density scaling power law, τα = f(T(-1)V(-γ)), recently acknowledged as a valid unifying concept in the glass transition physics, to differentiate between physically relevant and irrelevant attempts at formulating the temperature-volume representations of the Adam-Gibbs model. As a consequence, we determine a straightforward relation between the structural relaxation time τα and the configurational entropy SC, giving evidence that also SC(T, V) = g(T(-1)V(-γ)) with the exponent γ that enables to scale τα(T, V).

Elevated Serum Tryptase and Endothelin in Patients with ST Segment Elevation Myocardial Infarction: Preliminary Report.

Unlabelled: An inflammatory response plays a crucial role in myocardial damage after an acute myocardial infarction.

Objectives: To measure serum concentrations of several mediators in patients with an acute myocardial infarction (STEMI) and to assess their potential relationship with a risk of coronary instability.

Patients And Methods: The 33 patients with STEMI and 19 healthy volunteers were analyzed.

Successful versus unsuccessful antegrade recanalization of single chronic coronary occlusion: eight-year experience and outcomes by a propensity score ascertainment.

Aims: The effectiveness of revascularization of chronic total occlusion (CTO) remains intriguing. Thus, we sought to investigate whether a successful PCI for single CTO improves outcomes in a setting of stable angina and chronic occlusion of single coronary artery.

Methods And Results: Of 11 957 consecutive patients referred for nonurgent PCI between 2003 and 2010, 1110 displayed single CTO and were enrolled to the central CTO-registry database.

General rules prospected for the liquid fragility in various material groups and different thermodynamic conditions.

The fragility parameter has been acknowledged as one of the most important characteristics of glass-forming liquids. We show that the mystery of the dramatic change in molecular dynamics of systems approaching the glass transition can be better understood by the high pressure study of fragility parameters defined in different thermodynamic conditions. We formulate and experimentally confirm a few rules obeyed by the fragility parameters, which are also rationalized by the density scaling law and its modification suggested for associated liquids.