Can the tricyanomethanide anion improve CO2 absorption by acetate-based ionic liquids?

Carbon dioxide absorption by mixtures of two ionic liquids with a common cation-1-butyl-3-methylimidazolium acetate, [C4C1Im][OAc], and 1-butyl-3-methylimidazolium tricyanomethanide, [C4C1Im][C(CN)3]-was determined experimentally at pressures below atmospheric pressure as a function of temperature between 303 K and 343 K, and at 303 K as a function of pressure up to 10 bar. It is observed that the absorption of carbon dioxide decreases with increasing tricyanomethanide anion concentration and with increasing temperature, showing a maximum of 0.4 mole fraction of carbon dioxide in pure [C4C1Im][OAc] at 303 K. At this temperature, the CO2 absorption in the mixtures [C4C1Im][OAc](1-x)[C(CN)3]x is approximately the mole-fraction average of that in the pure ionic liquids. By applying an appropriate thermodynamic treatment, after identification of the species in solution, it was possible to calculate both the equilibrium constant, Keq, and Henry's law constant, KH, in the different mixtures studied thus obtaining an insight into the relative contribution of chemical and physical absorption of the gas. It is shown that chemical sorption proceeds through a 1 : 2 stoichiometry between CO2 and acetate-based ionic liquid. The presence of the C(CN)3- anion does not significantly affect the chemical reaction of the gas with the solvent (Keq = 75 ± 2 at 303 K) but leads to lower Henry's law constants (from KH = 77.8 ± 0.6 bar to KH = 49.5 ± 0.5 bar at 303 K), thus pointing towards larger physical absorption of the gas. The tricyanomethanide anion considerably improves the mass transfer by increasing the fluidity of the absorbent as proven by the larger diffusivities of all the ions when the concentration of the C(CN)3- anion increases in the mixtures.

The changing circumstance of atrial fibrillation - progress towards precision medicine.

The prevalence of atrial fibrillation (AF) in the general population is between 1% and 2% in the developed world and is higher in men than in women. The arrhythmia occurs much more commonly in the elderly, and the estimated lifetime risk of developing AF is one in four for men and women aged 40 years and above. Projected data from multiple population-based studies in the USA and Europe predict a two- to threefold increase in the number of AF patients by 2060. The high lifetime risk of AF and increased longevity underscore the important public health burden posed by this arrhythmia worldwide. AF has multiple aetiologies and a broad variety of presentations. The primary pathologies underlying or promoting the occurrence of AF vary more than for any other cardiac arrhythmia, ranging from autonomic imbalance to organic heart disease and metabolic disorders, such as diabetes mellitus, metabolic syndrome, hyperthyroidism and kidney disease, and lifestyle factors such as smoking, alcohol consumption and participation in endurance sports. Biomarkers are increasingly being investigated and, together with clinical and genetic factors, will eventually lead to a clinically valuable detailed classification of AF which will also incorporate pathophysiological determinants and mechanisms of the arrhythmia. In turn, this will allow the development and application of precision medicine to this troublesome arrhythmia.

Pulmonary vein triggers, focal sources, rotors and atrial cardiomyopathy: implications for the choice of the most effective ablation therapy.

Understanding of the pathophysiological mechanism(s) underlying atrial fibrillation (AF) is the foundation on which current ablation strategies are built. In the vast majority of patients with paroxysmal AF, the ablation procedure should target the pulmonary veins. In patients with nonparoxysmal AF, however, pulmonary vein isolation alone seems to be insufficient to prevent the arrhythmia. Several recent clinical trials have investigated the concept that rotors (re-entry based on a meandering central core from which spiral waves emanate) might be the mechanism responsible for sustaining AF. Ablation of these localized AF sources is an important step towards substrate-driven procedures in persistent AF. Hybrid AF ablation procedures, based on the integration of endocardial transcatheter and epicardial off-pump surgical techniques, have been introduced to overcome their mutual shortcomings. The long-term results are encouraging, especially in currently challenging settings such as nonparoxysmal AF and failed endocardial catheter ablation procedures.

The symbiosis of contact force catheter use for hybrid ablation for atrial fibrillation.

OBJECTIVE: Reconduction across an ablation line is a common reason for arrhythmia recurrence over time. The hybrid procedure combines epicardial ablation of the pulmonary vein (PV) and creation of a box lesion with endocardial touch-ups for any electrical gaps. A high contact force (CF) between the ablation tip and cardiac tissue may increase the risk of thrombus formation, catheter tip charring, steam pop formation, and even cardiac perforation. CF monitoring is a significant new parameter for titration of the CF for creating an adequate lesion. METHODS: Thirty-eight consecutive patients underwent epicardial ablation using bipolar radiofrequency devices. After checking electrical bidirectional block of the ablation lines, an endocardial CF catheter was used for further ablation (if needed) to complete the isolation of PVs, box lesion, cavotricuspid isthmus (CTI), and complex fractionated atrial electrograms (CFAE). RESULTS: Endocardial touch-up was needed for 2 PVs (1.3 %) and 10 (26.3 %) box lesions. It was also used for the CTI line in 7 (18.4 %) patients, atrial tachycardia in 3 (7.9 %) patients, and additional CFAE ablation in 17 (44.7 %) patients. All 5 patients with arrhythmia recurrence had a mean CF < 10 g (p = 0.03). Procedure duration was significantly shorter in the CF group (223 ± 57 vs. 256 ± 60 min, p = 0.03) compared with control group. CONCLUSION: Use of CF catheters is safe, feasible, and complementary to a hybrid procedure setup for atrial fibrillation ablation. Its real-time monitoring may predict future arrhythmia recurrence, and decrease procedure time.

Pressure effect on vibrational frequency and dephasing of 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids.

Raman spectra in the range of the totally symmetric stretching mode of the [PF6](-) anion, νs(PF6), have been measured for 1-alkyl-3-methylimidazolium ionic liquids [CnC1im][PF6], for n = 4, 6, and 8, as a function of pressure at room temperature. The ionic liquids [C6C1im][PF6] and [C8C1im][PF6] remain in an amorphous phase up to 3.5 GPa, in contrast to [C4C1im][PF6], which crystallizes above ~0.5 GPa. Equations of state based either on a group contribution model or Carnahan-Starling-van der Waals model have been used to estimate the densities of the ionic liquids at high pressures. The shifts of the vibrational frequency of νs(PF6) with density observed in [C6C1im][PF6] and in [C8C1im][PF6] have been calculated by a hard-sphere model of a pseudo-diatomic solute under short-range repulsive interactions with the neighboring particles. The stochastic model of Kubo for vibrational dephasing has been used to obtain the amplitude of vibrational frequency fluctuation, <Δω(2)>, and the relaxation time of frequency fluctuation, τc, as a function of density by Raman band shape analysis of the νs(PF6) mode of [C6C1im][PF6] and [C8C1im][PF6].

Reversal of ventricular premature beat induced cardiomyopathy by radiofrequency catheter ablation.

Frequent monomorphic ventricular premature beats (VPBs) may lead to left ventricular dysfunction. We describe two patients with frequent monomorphic VPBs and dilated cardiomyopathy in whom left ventricular function normalised after elimination of the VPBs by radiofrequency catheter ablation. The recent literature on this topic is summarised and potential candidates for catheter ablation are discussed. (Neth Heart J 2010;18:493-8.).

Interactions of fluorinated gases with ionic liquids: solubility of CF4, C2F6, and C3F8 in trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide.

The interactions between ionic liquids and totally fluorinated alkanes are investigated by associating gas solubility measurements with molecular simulation calculations. Experimental values for the solubility of perfluoromethane, perfluoroethane, and perfluoropropane in one ionic liquidtrihexyltetradecylphophonium bis(trifluoromethylsulfonyl)amide [P 6,6,6,14][Ntf 2]are reported between 303 and 343 K and close to atmospheric pressure. All mole fraction solubilities decrease with increasing temperature. From the variation of Henry's law constants with temperature, the thermodynamic functions of solvation were calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is always better than +/-3%. By the analysis of the differences between the solute-solvent radial distribution functions of perfluoromethane and perfluoropropane obtained by molecular simulation, it was possible to explain why solubility increases with the size of the perfluoroalkane. The trend of solubility is explained on the basis of the location of the solute with respect to the solvent ions as well as on the differences in the solute-solvent energies of interaction.

Computational and experimental investigations of supramolecular assemblies of p-sulfonatocalix[4]arene organized by weak forces.

We report the study of the supramolecular assemblies formed by the incorporation of quaternary ammonium cations such as Me4N+ or Et4N+ into host-guest assemblies with p-sulfonatocalix[4]arene in the presence of a lanthanide(III) cation in water. We use microcalorimetry to characterize the formation of these supramolecular assemblies. We obtain a molecular description of these assemblies by performing molecular dynamics simulations over a very large period of time. The structures of these supramolecular complexes have been determined and discussed through specific interaction energy contributions. By combining MD simulations and 1NMR spectroscopy, we highlight a specific behavior of the supramolecular assembly with the Me4N+.

Apical ballooning in relatives.

Apical ballooning of the left ventricle was first introduced as takotsubo-like left ventricular dysfunction in 1990 by Satoh and colleagues. The syndrome is characterised by reversible extensive akinesia of the apical and mid-portions of the left ventricle with hypercontraction of the basal segment. For the first time two sisters with this syndrome are reported, suggesting a possible genetic aetiology.

[Surgery for secondary and tertiary hyperparathyroidism: 11 years' experience]. / Cirugía del hiperparatiroidismo secundario y terciario: 11 años de experiencia.

From 1990 to september 2001, we have performed surgery in 22 patients diagnosed as Secondary hyperparathyroidism and three patients diagnosed as Tertiary, that were sent to our clinic from the Nephrology Department. These pathologies are rare in clinical practice but they mean a lot for the patient and his family. In 17 cases we performed a subtotal parathyroidectomy, in 2 cases a total parathyroidectomy and in another 2 an adenoma was found and excised. In one of these 22 cases and following a careful exam we did not final pathological parathynoids. We present and analysed here our results with an obvious improvement in all patients but one. Finally we carry out a revision of the literature comparing our results to other similar published series.

Cirugía del hiperparatiroidismo secundario y terciario: 11 años de experiencia / Surgery for secondary and tertiary hyperparathyroidism: an experience of 11 years

Desde 1990 hasta septiembre de 2001 hemos intervenido 22 pacientes diagnosticados de hiperparatiroidismo secundario y 3 con hiperparatiroidismos terciarios que fueron remitidos a nuestras consultas desde el Servicio de Nefrología. Estas patologías son poco frecuentes en la clínica pero suponen una carga gravosa para el paciente y su familia. En 17 casos realizamos una paratiroidectomía subtotal, en dos pacientes se realizó paratiroidectomía total y en otros dos se encontró un adenoma y se procedió a su extirpación. En 1 caso no hallamos paratiroides patológicas después de una búsqueda meticulosa. Recogemos y analizamos los resultados obtenidos comprobando la mejoría ostensible de todos los pacientes de nuestro estudio (excepto uno).Por último realizamos una revisión de la literatura al respecto comparando nuestros resultados con los de otras series publicadas (AU)

From 1990 to september 2001, we have performed surgery in 22 patients diagnosed as Secondary hyperparathyroidism and three patients diagnosed as Tertiary, that were sent to our clinic from the Nephrology Department. These pathologies are rare in clinical practice but they mean a lot for the patient and his family. In 17 cases we performed a subtotal parathyroidectomy, in 2 cases a total parathyroidectomy and in another 2 an adenoma was found and excised. In one of these 22 cases and following a careful exam we did not final pathological parathynoids. We present and analysed here our results with an obvious improvement in all patients but one. Finally we carry out a revision of the literature comparing our results to other similar published series (AU)

Determinación de PTH I en la cirugía del hiperparatiroidismo. Nuestra experiencia / PTH I assay in surgery of hyperparathyroidism. Our experience

Nuestro Servicio de ORL lleva realizadas un total de 90 paratiroidectomías desde abril de 1990 hasta el 2000 sobre 92 pacientes remitidos con diagnóstico de hiperparatiroidismo. De ellos, 67 pacientes fueron diagnosticados de hiperparatiroidismo primario; 22, secundario y 3 casos correspondían a hiperparatiroidismos terciarios. Analizamos una serie de variables preoperatorias y postoperatorias, entre las que destacamos la reciente determinación de los niveles de la PTH i rápida. El tipo de cirugía que realizamos fue la resección de adenoma en 63 casos; 23 pacientes fueron sometidos a una paratiroidectomía subtotal y 4 a paratiroidectomía total. En 2 pacientes intervenidos se realizó cirugía exploradora cervical sin hallar patología paratiroidea. Comparamos los resultados obtenidos con otras series publicadas y creemos útil la determinación de los niveles de paratohormona rápida (PTH i) pre y postoperatoria (actualmente sólo 3 casos) para predecir la respuesta clínica de los pacientes con diagnóstico de hiperparatiroidismo (AU)

Our Service of Otolaryngology has performed 90 parathyroidectomies at all since april 1990 to 2000 on 92 patients sent to us with diagnosis of hyperparathyroidism. 67 patients were diagnosed as primary hyperparathyroidism; 22 as secondary and 3 cases corresponded to tertiary hyperparathyroidism. We analysed a string of variables before and after the surgery standing out the recent estimate of rapid PTH i levels. The kind of surgery we performed was the removal of adenoma in 63 cases; 23 patients were put to subtotal parathyroidectomy and 4 to a total one. An exploratory neck surgery was performed in two patients without finding a parathyroid pathology. We compare the obtained results with other published series and we think it can be useful to determinate the rapid paratohormone levels (PTH i) pre and postsurgery (only used in 3 cases by now) in order to predict the clinic response of the patients with hyperparathyroidism (AU)

[Determination of PTH I in hyperparathyroidism surgery. Our experience]. / Determinación de PTH I en la cirugía del hiperparatiroidismo. Nuestra experiencia.

Our Service of Otolaryngology has performed 90 parathyroidectomies at all since april 1990 to 2000 on 92 patients sent to us with diagnosis of hyperparathyroidism. 67 patients were diagnosed as primary hyperparathyroidism; 22 as secondary and 3 cases corresponded to tertiary hyperparathyroidism. We analysed a string of variables before and after the surgery standing out the recent estimate of rapid PTH i levels. The kind of surgery we performed was the removal of adenoma in 63 cases; 23 patients were put to subtotal parathyroidectomy and 4 to a total one. An exploratory neck surgery was performed in two patients without finding a parathyroid pathology. We compare the obtained results with other published series and we think it can be useful to determinate the rapid paratohormone levels (PTH i) pre and postsurgery (only used in 3 cases by now) in order to predict the clinic response of the patients with hyperparathyroidism.