Operando XPS: A Novel Approach for Probing the Lithium/Electrolyte Interphase Dynamic Evolution.

The coupling protocols combining photoemission spectroscopy and other characterization methods such as electrochemical, electrical, optical, thermal, or magnetic paved the way to considerable progress in the field of materials science. Access to complementary data on the same object is relevant, but in the vast majority of cases, it is carried out sequentially and separately. This raises the complex question of the equivalence of the analyzed surfaces subjected to these different characterizations. In the frame of lithium ion battery technology (LIB), several techniques have been developed to follow in operando condition the reactivity of electro-active materials toward liquid or solid electrolytes. Besides the knowledge of the redox processes obtained using operando protocols, especially at the interfaces, some limitations associated with material sensitivity and/or the characterization techniques are still a breakdown to widen our understanding of the origin of the LIB performance degradation processes. Herein, we propose a new design of an operando cell adapted to perform X-ray photoemission spectroscopy (XPS) at the interface between electrode and electrolyte under electrochemical solicitations. To illustrate its performance, the crucial issues associated with the lithium metal interface have been scrutinized using Li/Li symmetrical cells and two types of ionic liquids, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C1C6ImTFSI) and 1-hexyl-3-methylimidazolium bis(fluorosulfonyl)imide (C1C6ImFSI) laden with LiTFSI salt. Our original setup allowed us to follow-up the lithium surface reactivity toward these ionic liquid based electrolytes in open circuit voltage condition and under polarization. Beside the gain of time and the matter saving, we highlighted and optimized the blocking issues to perform accurate OXPS measurement for probing the evolution of the chemical structure and the surface potential change at the interface lithium/electrolyte in dynamic mode.

New Interpretation of X-ray Photoelectron Spectroscopy of Imidazolium Ionic Liquid Electrolytes Based on Ionic Transport Analyses.

We reported a new perspective on the correlation between the electronic structure of an ionic liquid (IL)-based electrolyte probed by X-ray photoelectron spectroscopy and the transport properties analyzed by impedance spectroscopy. We highlighted the core level chemical shifts of 1-hexyl-3-methylimidazolium (bis(trifluoromethanesulfonyl)imide) (C1C6ImTFSI), 1-hexyl-3-methylimidazolium bis(fluorosulfonyl)imide (C1C6ImFSI), and 1-hexyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide (C1C1C6ImTFSI) laden with LiTFSI salt and vinylene carbonate (VC) or fluoroethylene carbonate (FEC) with regard to the transport properties of cations and anions. We pointed out based on detailed binding energy shift analyses a clear effect of the anion on the local organization of Li+ ions. The significant peak shift in the case of C1C6ImTFSI laden with LiTFSI corroborates the formation of [Li(TFSI)2]- complexes. On the contrary, the lower amplitude of the binding energy shift of C1C6ImFSI for both anion- and cation-related peaks indicates that the electronic distribution around the cation and the anion is not affected when the LiTFSI salt is added, which plays a strong role in the ion dynamics (lower viscosity) of the electrolyte. The X-ray photoelectron spectroscopy (XPS) result supports the preponderant role of imidazolium ionic liquid based on FSI anion to form an electrolyte less prone to form ionic complexes. The methylation of the imidazolium cation contributes to the reduction of the interaction between the C1C1C6Im cation and TFSI anion, while additives VC and FEC contribute to the change of the alkyl configuration in C1C6Im cation, leading to the modification of the macroscopic properties of the ILs.

Electrochemical Impedance Spectroscopy and X-ray Photoelectron Spectroscopy Study of Lithium Metal Surface Aging in Imidazolium-Based Ionic Liquid Electrolytes Performed at Open-Circuit Voltage.

Lithium reactivity toward an electrolytic media and dendrite growth phenomenon constitutes the main drawback for its use as an anode material for the lithium battery technology. Ionic liquids (ILs) were pointed out as promising electrolyte solvent candidates to prevent thermal runaway in a lithium battery system. However, the reactivity of lithium toward such a kind of an electrolyte is still under debate. In this study, the interaction between lithium metal and imidazolium-based ILs, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C1C6ImTFSI) and 1-hexyl-3-methylimidazolium bis(fluorosulfonyl)imide (C1C6ImFSI), has been investigated based on the nondestructive methodology coupling electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) in coin cells aged several days at open-circuit voltage. The main components detected by XPS in the bulk separator and at the surface of the lithium metal are the byproducts of cation and anion degradation. Similarities and differences were noticed depending on the anion nature of bis(trifluoromethylsulfonyl)imide versus bis(fluorosulfonyl)imide. The role of lithium salt addition (LiTFSI) was also pointed, giving rise to the stability improvement of the electrolytic solution toward the lithium anode. A direct correlation between the resistance of the bulk electrolyte and of the interface electrolyte/lithium and chemical composition changes were established based on a detailed EIS and XPS combined study.

Ablación cardiaca auricular: estrategias guiadas por el mapeo de electrogramas / Catheter Ablation for Atrial Fibrillation: Electrogram-Guided Methods

Resumen La ablación por radiofrecuencia se ha constituido como la técnica más utilizada para el tratamiento intervencionista de la fibrilación auricular. El aislamiento eléctrico de venas pulmonares se ha convertido en el procedimiento convencional, principalmente en pacientes con fibrilación auricular paroxística. Sin embargo, la tasa de éxito mediante esta técnica en pacientes con fibrilación auricular persistente es alrededor del 50%. Aunque se han propuesto diversas estrategias para guiar al electrofisiólogo en los procedimientos de ablación, estudios recientes muestran que la generación de líneas de ablación adicionales guiadas anatómicamente o mediante mapeo de electrogramas complejos fragmentados, no mejora la tasa de éxito del procedimiento convencional de aislamiento de venas pulmonares. En esta revisión, se consideran las limitaciones que representan los métodos de mapeo electrofisiológicos actuales, las nuevas estrategias de evaluación de los electrogramas y los métodos de procesamiento de señales que se ven propuestos en el futuro más inmediato, para guiar los procedimientos de ablación particularmente en pacientes con fibrilación auricular persistente.

Abstract Radiofrequency catheter ablation has evolved into an effective treatment option for drug-resistant patients with atrial fibrillation. Electrical isolation of the pulmonary veins has become the standard ablation strategy mainly in patients with paroxysmal atrial fibrillation. However, the success rate of pulmonary veins isolation is about 50% in patients with persistent atrial fibrillation. Although different strategies to guide the electrophysiologist in ablation procedures have been proposed. Recent studies show that the generation of additional ablation lines guided anatomically or by fragmented complex electrograms mapping does not improve the success rate of the conventional pulmonary veins isolation procedure. In this review, we describe the limitations of current electrophysiological mapping methods, the new electrogram evaluation strategies and the signal processing methods that are proposed in the immediate future, to guide ablation procedures, particularly in patients with atrial fibrillation persistent.

Fractionated electrograms and rotors detection in chronic atrial fibrillation using model-based clustering.

The identification of atrial fibrillation (AF) substrates is needed to improve ablation therapy guided by electrograms, although mechanisms that sustain AF are not fully understood. Detection of complex fractionated atrial electrograms (CFAE) is used for this purpose. Nonetheless, efficacy of this method is inadequate in the case of chronic AF. Recent hypothesis proposes the rotors as fibrillatory substrate. Novel approaches seek to relate CFAE with rotor; nevertheless, such methods are not able to identify the associated substrate. Furthermore, the patterns that characterize CFAE generated by rotors remain unknown. Thus, tracking of rotors is an unsolved issue. In this paper, we propose a non-supervised method to find patterns associated with fibrillatory substrates in chronic AF. We extracted two features based on local activation wave detection and one feature based on non-linear dynamics. Gaussian mixture model-based clustering was used to discriminate CFAE patterns. Resulting clusters are visualized in an electroanatomic map. We assessed the proposed method in a real database labeled according to the level of fractionation and in a simulated episode of chronic AF in which a rotor was detected. Our results indicate that the method proposed can separate different levels of fractionation in CFAE, and provide evidence that clustering can be used to locate the vortex of the rotors. Provided approach can support ablation therapy procedures by means of CFAE patterns discrimination.

Solid mesenchymal hamartoma in an adult: a case report.

Mesenchymal hamartoma of the liver (MHL) is an uncommon tumour composed of architecturally abnormal bile ducts in an uncommitted myxoid stroma. Most MHL are diagnosed in childhood and few cases have been reported in adults. This report describes a case of a well defined solid mass in the right lobe of the liver in a 51 year old man. Preoperative radiological examination revealed a large completely solid mass. Biopsy showed a dense fibrous stroma with hyalinisation and some bile ducts. A provisional diagnosis of MHL was made. Surgical excision was impossible and liver transplantation was undertaken. Definitive pathology confirmed the diagnosis. Review of published reports shows this to be the fourth case of MHL treated by liver transplantation.

Neumotórax catamenial recurrente / Recurrent catamenial pneumothorax

El neumotórax catamenial es una rara entidad caracterizada por la aparición de aire en el espacio pleural durante la menstruación. Su presentación clínica es muy variada, se asocia a endometriosis, y su diagnóstico se establece frecuentemente por las manifestaciones clínicas. El tratamiento de esta patología es controvertido, y se asocia a altas tasas de recurrencia. Presentamos un caso clínico de neumotórax recurrente en una paciente de 24 años, que presentó neumotórax derecho de repetición que coincidía con la menstruación, y que requirió tratamiento quirúrgico; se realizó el diagnóstico clínico de neumotórax catamenial (AU)

Experimental heterotopic heart transplantation: an easier technique.

AIM: The use of heterotopic heart transplantation (HHT) in experimental surgery is an extended method to evaluate cardiac graft viability. To study endothelial injury after ischemia-reperfusion, the technique described by Matsui et al. in 1988 for HHT was chosen. A modification, which consists of replacing the atrium-to-atrium anastomosis for the tip of a 30-Fr venous cannula, was developed with the purpose of using this technique in small pigs. Both techniques were compared. METHODS: Twenty-seven consecutive HHTs in 17- to 20-kg pigs using Matsui's original technique and the modified technique were performed. Ischemia time, bleeding volume, mean gradient and anastomosis complications were measured to compare both techniques. RESULTS: Statistically significant decreases in ischemia time, bleeding volume and mean gradient with the modified technique were found. Furthermore, there were two cases of suture dehiscence with the original technique. CONCLUSIONS: The replacement of the atrium-to-atrium anastomosis for the venous cannula is a modification that statistically decreases the ischemia time, blood loss and avoids suture complications. This modification makes Matsui's technique easier, faster and safer in small pigs and it may be used in bigger animals and in any kind of non-permanent anastomosis.

The transplantation donation process in the Centro de Investigaciones Medico Quirurgicas of Cuba: 1999-2002.

OBJECTIVE: In 1998 in the Centro de Investigaciones Medico Quirurgicas the Transplant Coordination Office (TCO) was created, with the aim to organize a system to support a hepatic transplantation program. This organization, which changed the transplantation-donation process not only in our center but in the whole country, is described in this article. METHOD: The files of donors generated in our hospital were studied together with the transplant coordination records, from 1999 till the first half of 2002. RESULTS: In the period studied, 21 potential donors were diagnosed with brain death, yielding a donation rate of 71.4%. Brain death was most frequently caused by vascular brain disease; however, in the realized donor group, the cranioencephalic trauma predominated. The typical donor was a man of average age 39.2 years (range, 18-86 years). Among the potential donors, 24% were excluded based on medical criteria, and 5% due to family objections. Forty liver transplantation were performed in 36 patients including 1 liver-kidney simultaneous procedure. The principal etiologies for transplant included hepatitis C virus cirrhosis, 22%; alcoholic, 19%; and acute hepatic failure, 13%. Kidney transplantations were performed in 70 patients, including 41 from cadaveric donors (53.6%) and 29 from living related donors (41.4%). In 2001, a pancreas-kidney transplantation program was started. CONCLUSION: The creation of the TCO has been of paramount importance to optimize transplantation program functions.

Left atrial thrombosis after heart transplantation.

Left atrial thrombosis in the absence of rheumatic heart disease and atrial fibrillation is a rare occurrence. We report two cases of left atrial pedunculated thrombus formation after orthotopic heart transplantation. Despite an uneventful post-operative course, sinus rhythm and normal contractility of the heart, large thrombi could be found several months following transplantation. Surgical thrombectomy was performed under cardiopulmonary bypass. Operative technique is proposed as one of the main factors that can contribute to left atrial thrombosis after heart transplantation.

Pulmonary hydatidosis: surgical treatment and follow-up of 240 cases.

OBJECTIVE: We review a series of 240 patients treated surgically for pulmonary hydatid cyst in our center between 1966 and 1988, assessing the results with our surgical technique, which involves a novel needle aspiration device designed by Professor D. Figuera, and postoperative treatment protocol. PATIENTS AND METHODS: The majority (60.4%) of the patients were from areas endemic for hydatid disease. The mean age of the patients at the time of the surgical procedure was 31.5 +/- 7.2 years (range: 4-70 years). A trocar-suction device was used for the needle aspiration of 276 (92%) of the 300 cysts encountered in the 240 patients. The remaining 24 cysts were removed integrally by means of different surgical techniques such as cyst enucleation, lobectomy, segmentectomy and atypical pulmonary resection. The residual cavity was treated by pericystectomy and eversion to the pleural surface in 238 cases (86.2%) and by capitonnage in 38 (13.7%). High vacuum suction (-30 cm H2O) was employed in every case. Depending on when the procedure was performed, the patients were treated with mebendazole or albendazole according to the protocol designed by Bekhti. RESULTS: Clinical assessment of the symptoms and plain chest X-ray led to the correct diagnosis in 228 cases (95%). In six (2.5%), imaging studies such as ultrasonography, computed tomography and nuclear magnetic resonance were required, and in the remaining six cases (2.5%), the diagnosis was established intraoperatively or in the subsequent histopathological study. One hundred and seventy patients (70.8%) presented a solitary lung cyst, while the remaining 70 (29.2%) were found to have multiple cysts in one or more lobes of one or both lungs. In addition, 45 patients (18.7%) presented hepatic cysts and 25 (10.4%) had cysts in other locations. After 18 years of follow-up, the survival rate was 94.6%. Of the surviving patients, 98.3% were free of pulmonary hydatid disease and 95.1% were free of hydatid disease. CONCLUSIONS: The trocar-suction device employed here for needle aspiration of hydatid cysts has demonstrated its efficacy in preventing the rupture of the cyst and its possible dissemination. With its use, the parasite is eradicated and the residual cavity can be excised.

[Heart transplantation in a patient with rheumatoid arthritis]. / Trasplante cardíaco en un paciente con artritis reumatoide.

A 56 year-old woman with rheumatoid arthritis was diagnosed with idiopathic dilated cardiomyopathy. She developed progressive heart failure that was refractory to conventional medical management. Heart transplantation was performed bearing in mind the controversy that surrounds its use in patients with a systemic disease. Transplant and rheumatoid arthritis were favorable at 33 month evolution. The immunosuppressive therapy required for the transplant helped the control of her articular disease.