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The cycling life of layered Ni-rich LiNi1-x-yCoxMnyO2 (NCM, 1-x-y ≥ 0.8) is typically extended by restricting the upper cut-off voltage during cycling to below 4.2 V, sacrificing, however, the untapped additional capacity above the cut-off voltage. To make this additional capacity available, we investigate graphite/LiNi0·8Co0·1Mn0·1O2 cells cycled to high upper cut-off voltages up to 4.5 V at high electrode areal capacities of 4.8 mAh/cm2 in a standard electrolyte consisting of 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate and ethylene methyl carbonate (ethylene carbonate:ethylene methyl carbonate = 3:7 vol% + 2% vinylene carbonate). Although the initial capacity reaches 190 mAh/g, the capacity retention after 300 cycles to 4.5 V is only 66%. Employing a combination of tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate as electrolyte additives, we demonstrate excellent capacity retention of 85% after 300 cycles to 4.5 V. Moreover, graphite/LiNi0·8Co0·1Mn0·1O2 cells with additives show improved capacity retention also at elevated temperatures of 60 °C. A detailed post-mortem analysis reveals the formation of a compact and LiF-rich and B-containing cathode/electrolyte interphase layer on the LiNi0·8Co0·1Mn0·1O2 particles cycled with tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate additives, substantially suppressing the transition metal dissolution and the cation-disordered layer formation on the exposed particles' surface., Materials Today Energy, 34

Lithium-ion batteries based on single-crystal LiNi

Developing high-energy-density cathodes with prolonged cycling life is crucial to the continuing success of lithium-ion batteries. In particular, nickel-rich layered LiNi0.8Mn0.1Co0.1O2 (NMC811) ca...

A Lei nº 11.769/2008 dispõe sobre a obrigatoriedade do ensino da música na educação básica. Mesmo após 12 anos da sanção da referida lei, muitas escolas não puderam efetivar sua implementação, pela falta de estrutura que apresentam ou pela superficialidade com que o ensino de música é tratado no Brasil. Dessa forma, este artigo apresenta o desenvolvimento de um software, que possa ser utilizado como auxiliar no processo de ensino-aprendizagem da música em escolas brasileiras de educação básica. O software é capaz de reconhecer e reproduzir elementos pertinentes à teoria musical a partir de partituras em formato PDF, tais como uma nota, pausa, compasso, duração das notas e andamento da música.

Using an epitaxial thin-film model system deposited by pulsed laser deposition (PLD), we study the Li-ion conductivity in Li4Ti5O12, a common anode material for Li-ion batteries. Epitaxy, phase purity, and film composition across the film thickness are verified employing out-of-plane and in-plane X-ray diffraction, transmission electron microscopy, time-of-flight mass spectrometry, and elastic recoil detection analysis. We find that epitaxial Li4Ti5O12 behaves like an ideal ionic conductor that is well described by a parallel RC equivalent circuit, with an ionic conductivity of 2.5 × 10–5 S/cm at 230 °C and an activation energy of 0.79 eV in the measured temperature range of 205 to 350 °C. Differently, in a co-deposited polycrystalline Li4Ti5O12 thin film with an average in-plane grain size of

Using an epitaxial thin-film model system deposited by pulsed laser deposition (PLD), we study the Li-ion conductivity in Li

Background A minimally invasive approach through an upper ministernotomy (UMS) has been used in our Division since 1997. On the basis of favorable outcome we have gradually extended this approach from isolated aortic valve replacement (AVR) to more complex cardiac surgery procedures and it is currently our first choice for a variety of procedures. Here we report our 11 years experience. Methods From 1997 to December 2007, 1,126 procedures were performed at our department, using UMS. Isolated procedures on the aortic valve were performed in 695 patients (61%). Isolated procedures on the aortic valve as redo operation were performed in 77 patients (7%). Complex cardiac surgery procedures (including double valve replacement-repair, ascending aorta-aortic arch replacement, aortic root replacement, aortic dissection, AVR combined with coronary surgery, and complex redo procedures) were performed in 354 patients (32%). Early postoperative outcome was evaluated considering three different groups according to the surgical procedure (first time AVR, redo AVR, and complex procedure). Results Overall conversion to full sternotomy was required in 16 patients (1.4%) with no significant differences between isolated AVR (9 patients, 1.3%) and complex or redo procedures (1 patient [1.2%] and 6 patients [1.6%], respectively). Forty-seven patients died in hospital (cumulative in-hospital mortality of 4.1 %). Mortality according to the procedure was 6.7, 3.8, and 2.8% for complex, redo AVR, or isolated AVR procedures, respectively, with a significant difference only for the complex procedures. Similarly, early postoperative outcome in terms of incidence of prolonged mechanical ventilation and ICU stay was significantly different only in the complex procedure group. Incidence of surgical revision (5.1, 2.9, and 2.7% for complex, redo, or isolated AVR procedures, respectively) showed no statistically significant differences regardless the type of procedures. Conclusions Our experience clearly shows that a minimally invasive approach through upper ministernotomy is feasible and safe not only for isolated AVR but that it can also be utilized for a variety of complex surgical procedures. Minimizing surgical access may be helpful in patients undergoing complex surgical procedures, especially redo procedures, without compromising the surgical result.

Objective The increasing number of patients awaiting heart transplant and the shortage of donors led to the development of a variety of left ventricular assist devices (LVAD). We analyse our experience in order to evaluate the efficacy of LVAD as bridge to transplant and the feasibility of permanent implantation. Patients The data are drawn from our experience on 50 patients, implanted with the Novacor LVAD and from a limited series of 4 patients implanted with a Lion Heart totally implantable permanent LVAD. Results Seventeen patients died on the device, 32 underwent heart transplant (9 died after transplant) and one is still on device. The causes of death were mostly related to cerebrovascular events or multi-organ failure. Cardiac output, wedge pressure, pulmonary vascular resistance and mean pulmonary pressure improved significantly. Cerebrovascular complications occurred mostly during the first 3 months of assistance, whereas the incidence of infections remained constant during the follow-up period. With a mean time of assistance of 211 days, we had only two cases of device malfunction. The four Lion-Heart patients experienced a clear improvement in hemodynamics but at a price of a significant complication rate. Three of them died after 418, 105 and 380 days of assistance. Device malfunction was observed in two cases. Conclusions LVAD Novacor has shown good hemodynamic improvement and reliable mechanical performance and long-term bridging can be considered fairly safe since most complications seem to occur within the first 90 days. Destination therapy with totally implantable devices seems to need further engineering and technical development.

More patients with end-stage heart failure are now being supported by left ventricular assist devices (LVAD) as a bridge to heart transplant. The LVAD unloads the failing heart and modifies the myocardial structure, with regression of left ventricular hypertrophy. The regression of hypertrophy has been reported histomorphologically in paired samples of myocardial tissues obtained from the same patient at the time of LVAD implantation and the heart excised at transplant. The understanding of the mechanisms of recovery may contribute to strategic development for LVAD weaning and the use of LVAD as a destination therapy.

Objective. The mechanisms of atrial fibrillation arc multiple reentry circuits spinning around the atrial surface, and these baffle any attempt to direct surgical interruption. The purpose of this article is to report the surgical experience in the treatment of isolated and concomitant atrial fibrillation at the Cardiac Surgical Institute of the University of Pavia. Methods. In cases of atrial fibrillation secondary to mitral/valve disease, surgical isolation of the left atrium at the time of mitral valve surgery can prevent atrial fibrillation from involving the right atrium, which can exert its diastolic pump function on the right ventricle. Left atrial isolation was performed on 205 patients at the time of mitral valve surgery. Atrial partitioning (maze operation) creates straight and blind atrial alleys so that non-recentry circuits can take place. Five patients underwent this procedure. In eight-cases of atrial fibrillation secondary to atrial septal defect, the adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation underwent surgical isolation of the right atrium associated which surgical correction of the defect, in order to let sinus rhythm govern the left atrium and the ventricles. Lone atrial fibrillation occurs in hearts with no detectable organic disease. Bi-atrial isolation with creation of an atrial septal internodal corridor was performed on 14 patients. Results. In cases of atrial fibrillation secondary to mitral valve disease, left atrial isolation was performed on 205 patients at the time of mitral valve surgery with an overall sinus rhythm recovery of 77%. In the same - period, sinus rhythm was recovered and persisted in only 19% of 252 patients who underwent mitral valve replacement along (P

Atrial tachycardia is an infrequent but potentially dangerous arrhythmia which often determines cardiac enlargement. Surgical ablation of the arrhythmia is effective and safe, provided a careful atrial mapping is performed and the surgical technique is tailored to the individual focus location. Eight patients underwent surgical ablation of ectopic atrial tachycardia between 1977 and 1990. Different techniques were adopted for each patient according to the anatomical location of the focus and possibly associated arrhythmias. Whenever possible, a closed heart procedure was chosen. In 1 patient a double focal origin was found and treated by separate procedures. In 1 patient with ostium secundum atrial septal defect and atrial flutter, surgical isolation of the right appendage and the ectopic focus was performed. In all patients ectopic atrial tachycardia was ablated with maintenance of the sinoatrial and atrioventricular nodal function as well as internodal conduction. In follow-up up to December 1991, no recurrency was recorded.

ObjectivesA multicentric European Clinical Study is ongoing to evaluate safety and efficacy of a new pulsatile implantable LVAD (BestBeat), smaller and lighter than similar devices, capable of providing synchronous and counterpulsating flow with respect to the LV of end-stage heart failure patients. Preliminary clinical results are reported.MethodsThe new BestBeat LVAD was used, consisting of an implantable pulsatile blood pump, electromechanically driven by a ball screw mechanism, and a wearable electronic controller and power sources. The clinical trial was conducted at 5 European centers. Adult patients affected by CHF in NYHA Class IV despite optimized medical treatment were enrolled. The primary study endpoint was survival at 90 days. Further study endpoints were maintenance of adequate LVAD pump flow and a minimum rate of adverse events during support.ResultsAs of June 2008, 6 patients received the implant. Cumulative support time was 3.7 years, median support time 176 days. All patients who completed the study survived except for one, who died after 48 days, due to combined infection and cerebrovascular accident. Another two patients died: one from intracranial bleeding 113 days after implant, and one from septic shock after 123 days. Hemodynamic improvement with Cl>2.0 l/min/m2and recovery of end-organ function expressed by consistent improvement of BUN, creatinine and bilirubin were reached in all patients. No device failure was observed. There was no bleeding requiring re-exploration, no hemolysis and only two device-related infections (both in one patient). Neurologic events were reported, the most serious ones occurring in patients with pre-implant respiratory and kidney failure. Three patients were discharged home. Two patients were successfully transplanted, one after 6 months and one after 13 months on device.ConclusionsGood performance and efficacy of the device were observed; the endpoints of the study were achieved, and its safety was consistent with expectations. The ongoing study will allow further conclusions to be drawn.

Purpose The aim of the present study is to describe our preliminary experience with the Arrow CorAide left ventricular assist system (LVAS). Description The Arrow CorAide LVAS is a small implantable, continuous flow centrifugal pump, with a fully suspended rotating assembly, intended as a bridge to transplant device, bridge to recovery, and for long-term use. Evaluation Since April 2005 we have implanted the CorAide LVAS in 2 male patients, with a patient follow-up of more than 6 months. Surgical procedures were uneventful, and both patients had an uneventful postoperative course, with fast weaning from mechanical ventilation and inotropic support. No thromboembolic events, infective complication, hemolysis, or mechanical failure occurred. To date, both patients are in New York Heart Association class I. Conclusions In our initial experience the CorAide LVAS blood pump is nonthrombogenic, nonhemolytic, and easy to implant. Both patients have improved their functional status. Further follow-up is needed to assess long-term results.

Objective: The great number of patients awaiting heart transplant and the shortage of donors has led to the increasing use of left ventricular assist devices (LVAD) for those patients that cannot wait only on medical therapy. In this study we analyze our experience in order to evaluate the possibility of long-term assistance. Methods: We have implanted LVAD Novacor in 36 patients with a mean age of 50.4 years. They were all critical candidates for transplant on high doses of inotrops. We evaluated the clinical and hemodynamic results and studied statistically the relative risk of complications at different time intervals of support. Results: In all cases we had a statistically significant improvement of: cardiac output, wedge pressure, pulmonary vascular resistance and mean pulmonary pressure. Eleven patients died on the device, 23 underwent heart transplant and two are still on the device. Causes of death were mostly related to cerebrovascular events or multiorgan failure. Seven of the 23 patients who underwent heart transplant died with a survival rate after transplant of 69.5% and an overall survival rate of 50%. Complications occurred in 33 patients with: 24 strokes, eight TIAs, four cerebral hemorrhages, three peripheral embolisms, seven cable infections, two pocket infections, two sepsis, two major lung infections, one mediastinitis, one right ventricular failure and three multiorgan failure. Time-related analysis showed that these complications occurred mostly during the first 3 months of assistance and this is particularly true for cerebrovascular events. The incidence of infections remained constant during the followup period. With a mean time of assistance of 203.1 days we had only two cases of device malfunction at 662 and 1297 days. Conclusions: LVAD Novacor has provided reliable mechanical performance and good hemodynamic improvement. Most complications seem to occur in the first 90 days, therefore long-term assistance could be considered. A reduction of the high rate of thromboembolic complications remains mandatory to improve the clinical results. q 2000 Elsevier Science B.V. All rights reserved.

We have developed and applied in 7 cases an alternative "orthodromic" technique for Novacor left ventricular assist device implantation. After sternotomy, the pocket is tailored, dividing the insertion of the diaphragm to the lower ribs, for easier bleeding control. On cardiopulmonary bypass, the aorta is cross-clamped and cardioplegia administered. Apical cannulation is performed first on a dry, still field. The device is then easily deaired, with blood flowing in the physiologic direction. The aorta is declamped and the outflow conduit is anastomosed. Before the suture is tied, the final deairing is obtained. This technique allows extreme precision in apical cannulation, easier control of bleeding, and accurate deairing of the pump. The ischemic time is short and damage to the right ventricle negligible.

Epicardial dissection without the use of cardiopulmonary bypass (CPB) was performed in 88 patients (56 males and 32 females, mean age 31.9 years). With intraoperative epicardial mapping, 101 accessory pathways were detected, with multiple pathways in 11 patients. CPB was avoided in all but one patient due to frequent onset of atrial fibrillation with rapid ventricular rate. Surgical ablation was successful in 86 patients (97.6%). Three patients required multiple surgical procedures because of persistence of conduction along a component of the original pathway. All but two patients were discharged without antiarrhythmic medication; these two patients were given quinidine therapy because of atrial fibrillation, but had normal early and late electrophysiological studies. Surgical ablation of Kent bundles by the epicardial approach for the treatment of Wolff-Parkinson-White syndrome can be achieved without the use of CPB. Optimal and steady exposure of the area are mandatory for the procedure, and dissection is eased by avoidance of heparin required for CPB.

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent mitral valve operations. From May 1989 to September 1991, 62 patients underwent mitral valve operations (group I); 19, mitral valve operations and DeVega tricuspid annuloplasty (group II); 15, mitral and aortic operations (group III); and 4, mitral and aortic operations and DeVega tricuspid annuloplasty (group IV). Left atrial isolation was performed, prolonging the usual left paraseptal atriotomy toward the left fibrous trigone anteriorly and the posteromedial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesions were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 patients (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (group I, 80.7%; group II, 68.5%; group III, 86.7%; group IV, 75%; p = not significant). Three late deaths (3.1%) were registered. Long-term results show persistence of sinus rhythm in 71% of group I, 61.2% of group II, 85.8% of group III, and 100% of group IV. The unique risk factor for late recurrence of atrial fibrillation was found to be preoperative atrial fibrillation longer than 6 months. Due to the satisfactory success rate in recovering sinus rhythm, we suggest performing left atrial isolation in patients with chronic atrial fibrillation undergoing valvular operations.

A 42-year-old male underwent Novacor left ventricular assist device. Readmitted after 11 months for fever and dyspnea, corynebacterium was isolated and treated with ampicillin and gentamicin for 6 weeks. Transplanted after 388 days on support, device inspection showed one leaflet of the porcine inflow valve perforated by endocarditis process (Fig. 1). www.elsevier.com/locate/ejcts European Journal of Cardio-thoracic Surgery 35 (2009) 910