Electrical coupling of individual electrocatalytic oscillators.

The catalytic electro-oxidation of some small organic molecules is known to display kinetic instabilities, which reflect on potential and/or current oscillations. Under oscillatory conditions, those systems can be considered electrocatalytic oscillators and, therefore, can be described by their amplitude, frequency, and waveform. Just like mechanical oscillators, the electrocatalytic ones can be coupled and their dynamics can be changed by setting different coupling parameters. In the present work, we study the unidirectional coupling of electrocatalytic oscillators, namely, those comprehending the catalytic electro-oxidation of methanol and formic acid on polycrystalline platinum in acidic media under potentiostatic control. Herein, we explore two different scenarios (the coupling of compositionally identical and non-identical oscillators) and investigate the effects of the master's identity and of the coupling constant on the slave's dynamics. For the master (methanol)-slave (methanol) coupling, the oscillators exhibited phase lag synchronization and complete phase synchronization. On the other hand, for the master (formic acid)-slave (methanol) coupling, the oscillators exhibited complete phase synchronization with phase-locking with a 2:3 ratio, complete phase synchronization with phase-locking with a 1:2 ratio, phase lag synchronization, and complete phase synchronization. The obtained results suggest that both the master's identity and the coupling constant (sign and magnitude) are parameters that play an important role on the coupled systems, in such a way that even for completely different systems, synchronization could emerge by setting a suitable coupling constant. To the best of our knowledge, this is the first report concerning the electrical coupling of hidden N-shaped-negative differential resistance type systems.

Verbascoside production in long-term Buddleja cordata Kunth cell suspension cultures.

Previously, our group reported the establishment of a white callus cell line of Buddleja cordata Kunth that is a high producer of the secondary metabolite, verbascoside (VB, also named acteoside), under suspension culture conditions. Here, we present experimental evidence of the sustained ability of that cellular line to grow and produce high amounts of VB for 5 years of continuous culture. Cellular line profiles were determined at the early (at the beginning) and late stages (at the end of 5 years of continuous subculturing) by analyzing relevant parameters of culture growth, i.e., specific growth rate [µ], doubling time [dt], and growth index [GI], as well as VB production. Late-stage cultures exhibited a 61% faster growth rate than early-stage subcultures, and 25 and 3% lower doubling time and growth index. The extents of growth phases were found to be different. Similar amounts of biomass were found (9.5 g and 9.4 g L-1). Verbascoside production increased parallel to cell growth; maximal yield level occurred in the mid-exponential phase and lasted until the end of the stationary phase (i.e., from the 15th to the 25th day and from the 9th to the 21st day for the early and late stages, correspondingly). The content of VB was higher in the late-stage culture (1.43 ± 0945 g L-1) than in the early-stage culture (1.21 ± 0.0286 g L-1). Productivity values point out the potential use of B. cordata cell line in the biotechnological production of VB and for research focused on the biochemistry of secondary metabolism.

Probing the surface fine structure through electrochemical oscillations.

In the course of (electro)catalytic reactions, reversible and irreversible changes, namely the formation of adsorbed poisons, catalyst degradation, surface roughening, etc., take place at distinct time-scales. Reading the transformations on the catalyst surface from the measurement of the reaction rates is greatly desirable but generally not feasible. Herein, we study the effect of random surface defects on Pt(100) electrodes toward the electro-oxidation of methanol in acidic media. The surface defects are gently generated in situ and their relative magnitudes are reproducibly controlled. The system was characterized under conventional conditions and investigated under an oscillatory regime. Oscillatory patterns were selected according to the presence of surface defects, and a continuous transition from large amplitude/low frequency oscillations (type L) on smooth surfaces to small amplitude/high frequency oscillations (type S) on disordered surfaces was observed. Importantly, self-organized potential oscillations were found to be much more sensitive to the surface structure than conventional electrochemical signatures or even other in situ characterization methods. As a consequence, we proved the possibility of following the surface fine structure in situ and in a non-invasive manner by monitoring the temporal evolution of oscillatory patterns. From a mechanistic point of view, we describe the role played by surface defects and of the adsorbed and partially oxidized, dissolved species on the oscillations of type S and L.

Encefalopatía traumática crónica, definición, diagnóstico y prevención: revisión de la literatura / Chronic traumatic encephalopathy, definition, diagnosis and prevention: review of literature

La encefalopatía traumática crónica (ETC) es una enfermedad neurodegenerativa que se produce como consecuencia traumatismos cerebrales repetitivos; concusiones, que son un síndrome clínico que se caracteriza por una alteración de la función cerebral. Una concusión, bajo su estricta definición, no debiese causar cambios estructurales en el cerebro por lo que no sería visible a través de imágenes, sí existen cambios a nivel microscópicos, bioquímicos y biomecánicos. La mayoría de los pacientes tienen completa resolución de sus síntomas dentro de 10 días (90 por ciento), pero existe un pequeño porcentaje que persiste con estos, pudiendo presentarse como un síndrome postconcusional, síndrome de segundo impacto o una encefalopatía traumática crónica. La ETC se caracteriza por la acumulación de prot-tau hiperfosforilada en neuronas y astrocitos. Estas se van a presentar en forma de ovillos o hilos neurofibrilares. En etapas iniciales las encontraremos de forma focalizada en la corteza frontal y en las formas más severas su distribución será más generalizada, distribuyéndose en la mayoría de las regiones del cerebro. Su diagnóstico se realiza a través de histopatología, por lo que hasta el momento sólo se ha logrado post-mortem. Se está trabajando en nuevas tecnologías asociadas a biomarcadores y PET para lograr una diagnostico premortem. El mayor énfasis en el manejo de esta taupatía es la prevención y adecuado manejo de las concusiones.

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease which is produced as a consequence of repeated brain trauma: concussions, which are a clinical syndrome characterized by an alteration in brain functions. A concussion, understrict definition, should not cause structural changes to the brain. Therefore, it would not be possible to see through images if there were changes at a microscopic, biochemical level. Most patients see their symptoms completely resolved within 10 days (90 percent), but there is a small percentage which persists, and these might cause a post-concussional syndrome, second impact syndrome of chronic traumatic encephalopathy. CTE is characterized by the accumulation of hyper-phosphorylated Tau protein in neurons and astrocytes. These appear in the form of neurofibrillary tangles. During the initial stages they are focalized in the frontal cortex and, in more severe cases, their distribution is more generalized, spreading through the majority of the regions in the brain. It is diagnosis is done through histopathology. Thus, it has only been possible to do post mortem. New technologies associated with bio-markers and PET are being worked on to achieve a pre-mortem diagnosis. The greatest emphasis in the handling of this tauopathy lies in the prevention and the adequate handling of concussions.

Safety of antitumour necrosis factor treatments in chronic rheumatic diseases: therapy discontinuations related to side effects.

WHAT IS KNOWN AND OBJECTIVE: The appearance of antitumor necrosis factor drugs (ATDs) has been a major advance in the management of these patients. However, due to the immunosuppressive effect of these therapies, side effects that require treatment discontinuations can appear. The purpose of this study was to evaluate the frequency of ATD discontinuation due to adverse drug effects (ADEs) and the influence of different factors such as diagnosis, ATD prescribed and concomitant disease-modifying antirheumatic drugs (DMARDs). METHODS: Observational study from a prospective cohort conducted in a tertiary hospital (1350 beds) in Spain. Data were obtained from the database of the Rheumatology Outpatient Unit of the hospital and patients' clinical files. Included patients had a diagnosis of RA or peripheral or axial SpA (ankylosing spondylitis, psoriatic SpA, non-radiographic SpA, SpA associated with inflammatory bowel disease or reactive arthritis) treated between November 2000 and March 2014 with infliximab (IFX), etanercept (ETN) or adalimumab (ADA). RESULTS AND DISCUSSION: Study cohort included 531 rheumatic patients (282 patients with RA, 53·1%, and 249 patients with SpA, 46·9%). ATDs were discontinued in 62 cases (11·7%) because of ADEs, mainly inmunogenicity and infections (mainly due to infusion reactions, 58·1%, and infections, 19·3%). ATD discontinuation was higher in the group of RA patients compared with SpA (44/282 (15·6%) in RA vs. 18/249 (7·23%) in SpA). The appearance of ADEs that led to drop out was more frequent in patients under IFX therapy (45 (18·6%) with IFX vs. 12 (7·59%) with ETN and 5 (3·81%) with ADA). We observed a significantly increased risk of ADEs when patients received IFX than when ETN or ADA were used (P < 0·001); 444 patients (83·6%) received DMARDs in combination with ATDs. The risk of ATD withdrawal was significantly higher in patients treated with leflunomide as compared to those who do not (OR = 1·984, P < 0·05). WHAT IS NEW AND CONCLUSION: Discontinuation of ATD due to ADEs is relatively frequent and it depends on the diagnosis and ATD administered. The risk of treatment discontinuation is higher in patients diagnosed with RA vs. SpA or treated with IFX (rather than with ETN or ADA). The addition of DMARDs to ATDs increased the frequency of treatment discontinuation, up to three concomitant medications. Leflunomide in combination with an ATD significantly increased the probability of treatment discontinuation due to adverse reactions.

Study of the influence of psychological factors in the etiology of vocal nodules in women.

OBJECTIVE: The role placed by certain psychological factors such as stress and personality on the development of vocal nodules has not yet been established. The aim of this case-control type study is to analyze the relationship between these psychological factors and the presence of vocal nodules while also considering the professional and social aspects of the subjects suffering from this pathology. METHODS: The case group is made up of 50 patients diagnosed with vocal nodules and with at least 6 months of evolution. The control group is made up of 50 patients diagnosed with nasal respiratory insufficiency. All the patients were examined by laryngeal stroboscopy. For the personality study, the perceived stress, and the voice use, the Minnesota Multiphasic Personality Inventory-2, Levenstein Perceived Stress Questionnaire, and Goldman Voice Use Survey were used, respectively. RESULTS: The subjects with vocal nodules presented a mean perceived stress score of 0.41±0.09, which was higher than that of the control group (0.35±0.06), the differences observed being statistically significant (P<0.001). In the personality study (MMPI-2), the only scale that was associated with the presence of the vocal nodules was that of psychomotor acceleration. The mean score obtained for the scale was 51.64±8.25 in the vocal nodule group and 45.02±0.06 in the control group (P<0.001). In the analysis of voice use, the subjects with vocal nodules scored 9.31±1.36, which was significantly higher than the score of the control group (8.07±1.24; P<0.001). In addition, other variables were associated with the presence of vocal nodules, such as being young and working in professions considered to be of vocal risk. CONCLUSIONS: Perceived stress and personality features of hyperactivity and impulsivity are independent factors related to vocal nodules.

Meningioma ventricular presentación infrecuente y revisión de la literatura / Infrequent intraventricular meningioma and review of the literature

Fundamento: Los meningiomas son tumores originados de las cubiertas aracnoideas. La localización intraventricular es rara especialmente los originados en el trígono ventricular derecho. Objetivo: Reportar un caso de localización atípica de un meningioma intracraneal. Presentación de caso: Paciente femenina de 68 años con historia de crisis convulsivas focales y cefalea de un mes de evolución. Las imágenes de Resonancia Nuclear Magnética convencionales, con secuencias en T1 y T2 axial y sagital, muestran una lesión localizada en el trígono ventricular derecho. Se realizó abordaje quirúrgico directo y excéresis total. El estudio anatomopatológico demostró un Meningioma fibroblástico. Discusión: Los meningiomas intraventriculares a nivel de trígono son infrecuentes y sólo se reportan series de pocos pacientes en la literatura. El abordaje y excéresis quirúrgica es el método de tratamiento de elección. Conclusiones: El abordaje y excéresis de meningiomas intraventriculares puede ser llevado a cabo exitosamente y en ausencia de complicaciones importantes.

Fundaments: Intraventricular meningiomas are rare often histologically benign tumors, especially those arisingfrom the right ventricular trigonal region. Objective: Report an unusual growth of intracranial meningioma. Case report: Authors present a clinical case of a 68 years old female with focal crisis and cephalea. Magnetic Resonance Imaging showed globular small hypo intense mass located in the right trigone. Surgical approach consisted in parietal craniotomy followed by dural opening and resection of the Intraventricular tumor. Post operatory evolution was adequate. Histological diagnosis was fibroblastic meningioma. Discussion: Meningiomas of the right lateral ventricule are rare and not widely reported. Surgical treatment is often successfully performed. Conclusion: Meningiomas of the lateral ventricles can be successfully diagnosed and surgically treated.

Cirugía mayor ambulatoria. Estudio de 1.028 operaciones de otorrinolaringología / No disponible

Introducción: Los servicios de otorrinolaringología (ORL) se han implicado desde el inicio de la cirugía mayor ambulatoria(CMA) en esta modalidad asistencial que permite una mejor utilización de los recursos disponibles con total satisfacción de los pacientes. Material y método: Se revisa un total de 1.028 pacientes programados por patología otorrinolaringológica en la unidad de CMA de nuestro hospital. El 30,6% correspondieron a patología laríngea; el 30,1% a patología otológica, y 39,2% a patología nasal y de tejidos blandos. Se trata de un estudio observacional obtenido de las bases de datos clínicas de la unidad, manejadas mediante el programa informático Stat View 5.1.0.Resultados: De las 1.028 intervenciones previstas, 20 fueron suspendidas (1,9%). El 74,5% de los pacientes fueron intervenidos bajo anestesia general; un 1,39% sufrieron complicaciones (..) (AU)

Background: Otolaryngology or ENT departments become involved since the beginning of day surgery in this health care modality that allows a better use of available resources with overall patient satisfaction. Materials and method: A total of 1028 patients, registered for ENT pathology in the day surgery unit of our hospital, have been studied. A 30.6% corresponded to laryngeal pathology,30.1% to ear pathology, and 39.2% to nasal pathology and soft tissues. It is an observational study obtained from the databases clinical unit, managed by the programme Stat View 5.1.0.Results: From 1,028 planned interventions, 20 were cancelled,1.9%. A 74,5% patients were operated on under general anaesthesia. A 1.39% suffered intraoperative complications, a 3.9% postoperative complications and a 1.78% needed unexpected hospitalisation. There was no mortality. Conclusions: Day surgery in ENT pathology confirms the success of day surgery, because with this modality of surgery is possible to obtain a correct treatment of patients with maximum safety and good acceptance both of patients and professionals (AU)

Mechanism and model of the oscillatory electro-oxidation of methanol.

A mechanism for the kinetic instabilities observed in the galvanostatic electro-oxidation of methanol is suggested and a model developed. The model is investigated using stoichiometric network analysis as well as concepts from algebraic geometry (polynomial rings and ideal theory) revealing the occurrence of a Hopf and a saddle-node bifurcation. These analytical solutions are confirmed by numerical integration of the system of differential equations.

Cirugía de los meningiomas intracraneales en el Servicio de Neurocirugía del Hospital Provincial Docente "Manuel Ascunce Domenech" / Intracraneal meningiona surgery at the Neurosurgery Service of Provincial Academic Hospital Manuel Ascunce Domenech

Se realizó un estudio descriptivo observacional de todos los pacientes diagnosticados de meningiomas Intracraneales en el Servicio de Neurocirugía del Hospital provincial Docente "Manuel Ascunce Domenech". Se determinó que los meningiomas Intracraneales resultaron más frecuentes en mujeres de la cuarta y quinta décadas de la vida, la cefalea, el déficit motor y las alteraciones mentales fueron los signos y síntomas neurológicos de mayor incidencia. La localización más frecuente de la lesión fue la de la convexidad frontal y resultó ser la de mejor grado de resección quirúrgica. El meningioma meningotelial, seguido del psamomatoso fueron los tipos histológicos predominante y las complicaciones respiratorias, la fístula de LCR y la sepsis quirúrgica ocuparon el primer lugar en cuanto a complicaciones. Se discuten y comparan estos resultados con la literatura nacional e internacional.

A descriptive observational study was run on all patients with intracranial meningiomas diagnosis at the Neurosurgery Department of the Academic Hospital "Manuel Ascunce Domenech". The result was that intracranial meningiomas are more frequent in women in their forties and fifties, migraine, motor deficit and mental disturbances were the neurological signs and symptoms of main incidence. The most frequent location of the lesion was the frontal convexity and proved to be of the best level of surgical resection. The meningiothelial meningioma followed by the psammomatous were the predominant histological types as well as the respiratory complications. As for complications the CSV fistula and surgical sepsis were on the first place. These results are discussed and compared with national and international literature.

Pericytes. Morphofunction, interactions and pathology in a quiescent and activated mesenchymal cell niche.

We review the morphofunctional characteristics of pericytes and report our observations. After a brief historical background, we consider the following aspects of pericytes: A) Origin in embryonic vasculogenesis (mesenchymal stem cells, neurocrest and other possible sources) and in embryonic and postnatal life angiogenesis (pre-existing pericytes, fibroblast/ myofibroblasts and circulating progenitor cells). B) Location in pericytic microvasculature and in the other blood vessels (including transitional cell forms and absence in lymphatic vessels), incidence (differences depending on species, topographical location, and type and stage of vessels) and distribution (specific polarities) in blood vessels. C) Morphology (cell body, and longitudinal and circumferential cytoplasmic processes), structure (nucleus, cytoplasmic organelles and distribution of microtubules, intermediate filaments and microfilaments) and surface (caveolae system). D) Basement membrane disposition, formation, components and functions. E) Contacts with endothelial cells (ECs) (peg and socket arrangements, adherent junctions and gap junctions) and with basal membrane (adhesion plaques). F) Molecular expression (pericyte marker identification). G) Functions, such as vessel stabilization, regulation of vascular tone and maintenance of local and tissue homeostasis (contractile capacity and vessel permeability regulation), matrix protein synthesis, macrophage-like properties, immunological defense, intervention in coagulation, participation in mechanisms that regulate the quiescent and angiogenic stages of blood vessels (including the behaviour of pericytes during sprouting angiogenesis and intussuceptive vascular growth, as well as pericyte interactions with endothelium and other cells, and with extracellular matrix) and plasticity, as progenitor cells with great mesenchymal potential, originating other pericytes, fibroblast/myofibroblasts, preadipocytes, chondroblasts, osteoblasts, odontoblasts, vascular smooth muscle and myointimal cells. This mesenchymal capacity is seen in a broad section on the perivascular mesenchymal cell niche hypothesis and in the concept of pericyte and EC "marriage and divorce". H) Peculiar pericyte types, such as hepatic stellate cells (Ito cells), bone marrow reticular cells and mesangial cells. I) Involvement in pathological processes, such as repair through granulation tissue, pericyte-derived tumors, tumor angiogenesis and tumoral cell metastasis, diabetic microangiopathy, fibrosis, atherosclerosis and calcific vasculopathy, lymphedema distichiasis, chronic venous insufficiency, pulmonary hypertension, Alzheimer disease and multiple sclerosis. J) Clinical and therapeutic implications (de-stabilization of vessels or formation of a stable vasculature).

Histogenesis and morphofunctional characteristics of chromaffin cells.

This article reviews the current status of research about the histogenesis and morphofunctional characteristics of chromaffin cells in the adrenal medulla. First, this study reports the selective migration, transcription and activation factors, and the morphological events of the chromaffin cell precursors during adrenal medulla development. Subsequently, the morphofunctional characteristics of adrenergic and non-adrenergic cells are considered, with particular reference to the characteristics of chromaffin granules and their biological steps, including their formation, traffic (storage, targeting and docking), exocytosis in the strict sense and recapture. Moreover, the relationship of chromaffin cells with other tissue components of the adrenal medulla is also revised, comprising the ganglion cells, sustentacular cells, nerves and connective-vascular tissue.

Cell contribution of vasa-vasorum to early arterial intimal thickening formation.

In occluded femoral artery segments, intimal thickening occurred and abundant neovascularization from the surrounding microcirculation developed. Under these conditions, the contribution of vasa-vasorum as a source of supplementary population of cells during the early intimal thickening formation was studied. Using a technique that specifically labels venules, predominantly postcapillary venules, a marker-Monastral Blue B-was used as a tracer to follow the pericyte, endothelial cell and monocyte/macrophage lineages. In the first two days of the experiment, the marker was restricted to the wall of the periarterial microcirculation, being incorporated by endothelial cells, pericytes and some monocytes/macrophages crossing the venule walls. Later, the marker continues to be observed in some of the following cells: endothelial cells and pericytes of the newly-formed vessels, fibroblast-like cells, transitional cells between pericytes and fibroblast-like cells, macrophages migrating into the interstitium, myointimal cells and neoendothelial cells of the arterial lumen. These findings provide evidence that, during arterial intimal thickening formation in occluded arterial segments, the periarterial microvascularization contributes, in addition to recruited macrophages, newly-formed endothelial cells and a supplementary population of fibroblast-like cells and myointimal cells.

Adult stem and transit-amplifying cell location.

Adult stem cells (ASC)--able to self renew and to intervene in maintaining the structural and functional integrity of their original tissue--can express greater plasticity than traditionally attributed to them, adopting functional phenotypes and expression profiles of cells from other tissues. Therefore, they could be useful to regenerative medicine and tissue engineering. Transit-amplifying cells (TAC) are committed progenitors among the ASC and their terminally differentiated daughter cells. The ASC reside in a specialized physical location named niche, which constitutes a three-dimensional microenviroment where ASC and TAC are protected and controlled in their self-renewing capacity and differentiation. The niche can be located near or far from the recruitment point, requiring a short or long-distance cellular migration, respectively. This paper briefly reviews the current status of research about ASC plasticity, transdifferentiation, fusion and functional adaptation mechanisms. Subsequently, ASC and TAC occurrence, characteristics and location have been considered in the skin, cornea, respiratory tract, teeth, gastrointestinal tract, liver, pancreas, salivary glands, kidney, breast, prostate, endometrium, mesenchyma, bone marrow, skeletal and cardiac muscle, nervous system and pituitary gland. Moreover, the role of cancer ASC has also been revised.

Implantación coclear con bisturí armónico Ultracision® / Cochlear implants using the Ultracision® harmonic scalpel

Hemos valorado la utilidad, indicaciones e inconvenientes del bisturí armónico Ultracision®, en la implantación coclear, así como sus ventajas respecto de otros sistemas de electrocoagulación. Estos aspectos se analizaron en 50 implantes cocleares realizados a lo largo de estos últimos años. Como conclusión, hay que establecer que el bisturí armónico Ultracision ® encuentra sus indicaciones más importantes en el campo de la otología, en aquellos casos en los que el implante coclear está insertado en la cóclea y es necesario utilizar un sistema de electrocoagulación o incisión, con fines diversos. En la mencionada situación, el bisturí armónico Ultracision® se mostró rápido, eficaz y seguro y con evidentes ventajas respecto del corte frío o de la electrocoagulación bipolar

We have evaluated the utility, indications and disadvantages of the Ultracision® harmonic scalpel, in the cochlear implants, and his advantages compare to other electrocoagulation´s systems. These aspects were evaluated in 50 cases of cochlear implants, made along the last years. We concluded that the Ultracision® harmonic scalpel is indicated, mainly, in the otology field, in these situations in wich the cochlear implant is in the cochlea, and is mandatory the use of an electrocoagulation system. In this situation, the Ultracision® harmonic scalpel was quick, safe and sure, and with many advantages, over the traditional scalpel and the bipolar diathermy

Asymmetric target patterns in one-dimensional oscillatory media with genuine nonlocal coupling.

We report the observation of a self-organized asymmetric wave source in a one-dimensional (1D) electrochemical system, namely, the hydrogen oxidation reaction on Pt in the presence of poisons. Numerical simulations reveal that the nonlocal migration coupling is crucial for the endogenous persistence of the perturbation that causes the asymmetry. Experiments and simulations agree perfectly for the regular and irregular variant of these asymmetric waves, manifesting the existence of nonlocal coupling induced patterns also in physical systems.

[Goya, his deafness and his time]. / Goya, su sordera y su tiempo.

We have made a bibliographyc review of the most important otology books from the end of the XVIII to the begining of the XIX century. We propose several hipothesis of the diagnoses and treatment of Goya's deafness in relation to the contemporary otological advances.

Goya, su sordera y su tiempo / Goya, his deafness and his time

Hemos realizado una revisión bibliográfica de las sobras más representativas de la otología del final del siglo XVIII y principios del siglo XIX. Se plantean diferentes hipótesis sobre el diagnóstico y el tratamiento de la sordera de Francisco de Goya en base a los avances otológicos de su época

We have made a bibliographyc review of the most important otology books from the end of the XVIII to the begining of the XIX century. We propose several hypothesis of the diagnoses and treatment of Goya´s deafness inrelation to the contemporary otological advances

Pattern formation in stiff oscillatory media with nonlocal coupling: a numerical study of the hydrogen oxidation reaction on Pt electrodes in the presence of poisons.

The impact of the strength of negative (desynchronizing) global coupling (NGC) on the spatiotemporal dynamics of an electrochemical relaxation oscillator is studied numerically with a prototypical model, the electro-oxidation of hydrogen in the presence of poisons. The results are compared with recent experiments. The NGC has a destabilizing effect on the homogeneous oscillations. Both, in theory and in experiments, the basic patterns found with increasing global coupling strength are modulated oscillations, target patterns (including an asymmetric variant), and modulated pulses, the average spatial inhomogeneity during an oscillation increasing with the intensity of the NGC. It is suggested that this scenario is typical for strong relaxation oscillations, and a comparison with an electrochemical oscillator exhibiting harmonic oscillations points to the fact that the critical coupling strength, upon which the complete synchronization is destroyed, is larger for relaxation oscillations than for harmonic oscillations. In addition, the numerical simulations predicted two- and three-phase cluster patterns at high coupling strength. Also in experiments cluster patterns were observed, however only in parameter regions of the local dynamics which were different from the one investigated in this study.

[Cochlear implants using the Ultracision harmonic scalpel]. / Implantación coclear con bisturí armónico Ultracision.

We have evaluated the utility, indications and disadvantages of the Ultracision harmonic scalpel, in the cochlear implants, and his advantages compare to other electrocoagulation's systems. These aspects were evaluated in 50 cases of cochlear implants, made along the last years. We concluded that the Ultracision harmonic scalpel is indicated, mainly, in the otology field, in these situations in wich the cochlear implant is in the cochlea, and is mandatory the use of an electrocoagulation system. In this situation, the Ultracision harmonic scalpel was quick, safe and sure, and with many advantages, over the traditional scalpel and the bipolar diathermy.