Environmental risks and mechanical evaluation of recycling red mud in bricks.

More and more by-products are being used in certain materials, especially in the construction industry. Natural construction materials contain amounts of heavy metals and radionuclides, but when by-products are used in these kinds of materials, this could lead to a growth in their concentrations and have a negative impact on public health.In this paper, red mud was used as a raw material (as a clay substitute) to manufacture fired bricks. Physical, mechanical, radiological and heavy metal leaching properties of fired bricks with a replacement ratio of up to 80 wt% of clay to red mud are discussed. In addition, the effect of different sintering temperatures (1173K and 1373K) was analyzed, and results showed that the higher the temperature produced, the higher the mechanical strength.To environmentally characterize materials, they were subjected to two different leaching tests: a batch test for raw materials and a monolithic test for the bricks, respectively. The results obtained were compared with the limits stated for several heavy metals by the European Landfill Directive. Results showed that red mud gives leachate concentration values for Cr higher than the limits stated for non-hazardous by-products. Bricks do not exhibit the same problem in the samples containing a high RM proportion and manufactured at a low sintering temperature (1173K), although in the case of V, a high concentration is observed.The contents of radionuclides such as Ra-220, Th-232 and K-40 of the final construction materials were analyzed and compared with different indexes. This paper indicates the maximum amounts of RM that can be used to replace clay for the manufacture of fired bricks without environmental risk.

Numerical tool for estimating the dielectric constant, the thickness, and the coverage of immobilized inhomogeneous protein films on gold in aqueous solution.

A numerical simulation tool is reported for nanometer thin and inhomogeneous immobilized protein films on gold in aqueous solution. It allows for the first time, to the best of our knowledge, the simultaneous assessment of refractive index, film thickness, and surface coverage. The model relies on and combines the convective diffusion equation, the Langmuir adsorption isotherm, and the Helmholtz equation, with appropriate boundary conditions. These three differential equations were jointly solved using a multiphysics software. The physical film parameters were extracted employing an optimization procedure for immobilized bovine serum albumin, hemoglobin, and neutravidin films. The relatively good agreement between the extracted values for the refractive index, film thickness, and surface coverage and the corresponding values reported in the open literature show the correctness of the proposed methodology.

Improved recycling of a gasification fly ash: An integrated waste management approach within the framework of a Circular Economy.

A Circular Waste Management alternative is considered in this paper in which a complete ash valorization process is proposed for an Integrated Gasification with Combined Cycle fly ash, trying to extract maximum value from this waste before it is discarded. In the paper, germanium, a scarce resource vital in our modern society, is first extracted from fly ash using water, with an extraction yield of 85%, and subsequently, the leached fly ash is used in the manufacture of fire-resistant boards containing 60% ash, thereby avoiding its disposal in a landfill. The potential environmental impact caused by the two stages of the process was analyzed, and the final effluent was considered to achieve a zero-discharge objective. This paper contributes to the development of a more sustainable management alternative for an industrial waste produced in increased amounts and provides the basis for a symbiotic coupling relationship among various industrial sectors.

A novel simulador for agile and graphical modeling of surface plasmon resonance based sensors.

Surface plasmon resonance (SPR) sensor is a consolidated technology for analysis of biomolecular interaction, largely applied in biology and pharmaceutical research. The simulation of the surface plasmon optical excitation response is an important step in the development process of SPR based sensors. The structure, design and configuration of the desired sensor benefits from a previous simulated analyses of the generated responses, defining operational conditions and feasibility of the selected materials to composed the optical coupling layers. Here an online web-based SPR sensor's simulator is presented. With a visual-oriented interface, enable drag & drop actions to easily and quickly model a variety of sensor arrangements. Presenting an embedded materials database for metals, glasses, 2D materials, nanoparticles, polymers, and custom substances, the simulator enables flexible configuration for sensors operating in angular and spectral modes, as well as localized SPR. The light propagation through the multilayer of materials is presented in terms of Fresnel coefficients, which are graphically displayed. The so-called SPR morphology parameters can be visualized. Moreover, sensor dynamic behavior could be knowledge by a Sensorgram simulation. Localized surface plasmon resonance (LSPR) in homogeneous and spherical nanoparticles is also present in the simulator. Simulated scenario's in various configurations, designs and excitation were performed and compare with other simulator. The proposed simulator guarantees comparable results with low-code, agile, and intuitive flow of execution.

Study of seashell waste recycling in fireproofing material: Technical, environmental, and economic assessment.

The productive sector must incorporate waste into traditional materials in order to grow sustainably. In Galicia (Spain) alone, the canning industry produces over 150,000 metric tons of seashell waste per year. Most of this waste is still disposed of in landfills or open fields due to the lack of a technically feasible, environmentally sustainable, and economically profitable recycling alternative. This paper aims to study the feasibility of a new recycling alternative for seashell waste from industrial canning, based on the production of fireproof material suitable for construction use. The waste was pre-treated in order to remove salts and remaining organic matter and reduce particle size. According to international standards, physical, mechanical, and insulating properties were assessed for four compositions: 0, 40, 60 and 80% of gypsum substituted with pre-treated seashell waste. Results showed that substitution of up 60% gypsum was technically feasible. A Life-Cycle Assessment and a preliminary production cost analysis were performed by analysing a recycling case in Galicia. The case study found that 40-60% gypsum substitution obtained an environmental impact reduction of 0.4%-59% for 13 of the 18 impact categories considered compared with 0% substitution. Increases in the other 5 categories were analysed due to aquatic emissions released in the waste pre-treatment washing process. The locations of the fireproof material production facility and the waste source were a key factor. Production costs could be reduced by 20-31% by using 40-60% gypsum substituted with seashell wastes.

A porous geopolymer based on aluminum-waste with acoustic properties.

Paval, a solid waste stream from the aluminum industry, is used as a pore generation agent in geopolymers. Paval was mixed with coal combustion fly ash, as a geopolymeric precursor, and activated with alkaline solution with the aim of obtaining porous geopolymers to be used as noise barriers. Both geopolymeric and pore generation reactions happen simultaneously. Aluminum from Paval can react with water and OH¯ from the geopolymerization activating solution, producing hydrogen. The hydrogen gas released generates a highly porous material. The influence of the fly ash-paval proportion and the setting temperature on open porosity, compressive strength and noise-absorbing properties were evaluated. To better understand these influences, the setting time, volume expansion and mineral composition were also studied. The obtained results showed that a higher Paval content (fly ash-Paval ratio 50:50) and setting temperature (70 °C) produced a lower setting time and higher volume expansion, increasing the open porosity and improving acoustic properties, but reducing the compressive strength. The material manufactured under these conditions showed similar amorphous phase content to the non-porous geopolymers made without Paval. On the other hand, the obtained materials did not raise environmental concerns in a normalised leaching test.

Hemodynamic changes detected by Doppler ultrasonography in the ovaries of cattle during early development of cystic ovarian disease.

A common reproductive disease in dairy cattle is Cystic Ovarian Disease. To study its development, there was use of an experimental model of follicular persistence to detect hemodynamic changes occurring in ovaries by using Doppler ultrasonography. After estrous synchronization, control cows received no additional treatment and were evaluated at proestrus (CG), whereas treated cows (PG) received sub-luteal doses of progesterone for 15 days and were evaluated at proestrus, and after 0, 5, 10 and 15 days of follicular persistence. Spectral Doppler was used to evaluate blood flow in the ovarian artery, and power Doppler for evaluation of blood flow in the ovarian parenchyma and follicular wall of persistent and dominant preovulatory follicles. Findings using power Doppler signals indicated there were no differences between groups in the parenchyma of both right (P =  0.455) and left (P =  0.762) ovaries. In contrast, power Doppler signals of blood flow were less in walls of persistent follicles from day 0 to 15 when there was follicular persistence than in dominant follicles of the CG (P <  0.001). Blood flow in ovarian arteries was less (P <  0.05) in diastolic velocity and time averaged maximum velocity in all PG groups than in the CG. Peak systolic velocity was less (P <  0.05) in all PG than in the CG, with the exception of P15 (P >  0.05). These findings indicate there are marked changes in blood irrigation area of walls of persistent follicles during the 15 days of follicular persistence.

Umbrales auditivos en pacientes con enfermedad de Méniere manejados con corticoides transtimpánicos / Hearing thresholds in Ménière's disease patients managed with transtympanic dexametasone

Introducción: Pese a que el uso de corticoides transtimpánicos en pacientes con enfermedad de Méniere es habitual en muchos centros, la evidencia respecto de su efecto sobre los umbrales auditivos es aún controversial. Objetivo: Estudiar los umbrales auditivos de pacientes con enfermedad de Méniere que recibieron corticoides transtimpánicos en el Servicio de Otorrinolaringología del Hospital Clínico de la Universidad de Chile. Material y Método: Estudio retrospectivo de pacientes con enfermedad de Méniere que consultaron entre los años 2015 y 2021. Se estudiaron los umbrales auditivos, antes y después de 3 inyecciones de dexametasona transtimpánica. Resultados: Se obtuvieron datos completos de 27 pacientes. Al comparar el promedio tonal puro antes y después del tratamiento, no se observaron diferencias significativas. A nivel individual, la variación de cambio de los umbrales auditivos con dexametasona se correlaciona en forma significativa con los umbrales auditivos previos a las inyecciones y con el tiempo transcurrido desde la última inyección, pero no con la edad. Conclusión: La terapia con dexametasona transtimpánica en pacientes con enfermedad de Méniere no altera los umbrales auditivos. Sin embargo, se requieren más estudios, para comprobar, si existe un efecto transitorio en los umbrales auditivos de los primeros días posterior al procedimiento.

Introduction: Although transtympanic corticosteroids are proposed in Méniere's disease patients refractory to standard medical therapy, the evidence regarding the effect of transtympanic corticosteroids on hearing thresholds is still controversial. Aim: To study the hearing thresholds of patients with Méniere's disease who were administrated with transtympanic corticosteroids at the Otorhinolaryngology Service of the University of Chile's Clinical Hospital. Material and Method: Retrospective study of Méniere's disease patients who consulted between 2015 and 2021. Demographic variables and hearing thresholds were studied before and after three transtympanic injections of dexamethasone. Results: A total of 27 patients were studied. There were non-significant differences in pure-tone hearing threshold averages before and after the injections. Individual variation in hearing thresholds correlates significantly with the pre-injection hearing thresholds and the period since the last injection, but not with age. Conclusion: Transtympanic dexamethasone therapy in patients with Meniere's disease does not alter hearing thresholds. However, more studies are needed to verify whether there is a transitory effect on hearing thresholds in the first days after the procedure.

Altered expression of cytokines IL-1α, IL-6, IL-8 and TNF-α in bovine follicular persistence.

In dairy cattle, cystic ovarian disease (COD) is an important cause of subfertility, and two of the main signs are ovulation failure and follicular persistence. The aim of this study was to examine the expression of the cytokines IL-1α, IL-6, IL-8 and TNF-α in ovarian follicular structures at different times of persistence in a model of follicular persistence induced by prolonged treatment with progesterone in dairy cows. Protein expression of IL-1α, IL-6, IL-8 and TNF-α was evaluated by immunohistochemistry. Additionally, IL-6 concentration in follicular fluid and serum was determined by ELISA. IL-1α, IL-6, IL-8 and TNF-α expression was increased in follicles with different persistence times in relation to the control dominant follicles, in granulosa cells. For IL-6, IL-8 and TNF-α, this increase was detected early (P0: expected time of ovulation and/or P5: 5 days of follicular persistence). Additionally, theca cells showed an increase in IL-6 in antral (groups P10 and P15) and persistent follicles (group P10) related to dominant follicles from the control group (p < 0.05). Serum concentration of IL-6 was higher in groups P5, P10 and P15 than in control cows (p < 0.05). The results show evidence that early development of COD in cows is concurrent with altered expression of these cytokines in different ovarian follicular structures and may contribute to the follicular persistence and endocrine changes found in cattle with follicular cysts.

[Disability after stroke: a longitudinal study in moderate and severe stroke patients included in a multidisciplinary rehabilitation program]. / Ictus y discapacidad: estudio longitudinal en pacientes con discapacidad moderada-grave tras un ictus incluidos en un programa de rehabilitacion multidisciplinar.

INTRODUCTION: Stroke is a recognized cause of disability among adults. However the impact that the deficits that occur after a moderate/severe stroke have on long-term disability, as well as the response of the resultant deficits to rehabilitation, are not completely understood. PATIENTS AND METHODS: A total of 396 patients with a modified Rankin score >= 3 after an ischemic (n = 221) or hemorrhagic (n = 175) stroke were included in this study. All patients were assessed with cognitive, behavior, emotional, motor and functional domains. All patients were assessed at baseline and six months after inclusion in a multidisciplinary rehabilitation program. RESULTS: Risk of falling (Berg Balance Scale < 45 in 83.1% of the sample at baseline and 49.5% at follow-up) and functional problems (82.8% with a Barthel Index < 75 at baseline and 53% at follow-up) were the most prevalent deficits. Emotional disturbances were those that most improved while behavioral problems were those that did less. Although global disability improved during treatment among most patients, only 11% of our patients, especially those with preserved cognitive function at baseline, could be classified as patients with mild disability at follow-up. CONCLUSIONS: Stroke consequences are multidimensional. The symptoms that the stroke can cause in multiple domains, as well as the pattern of recovery are widely diverse, with prevalence of behavioral long-term disturbances.

TITLE: Ictus y discapacidad: estudio longitudinal en pacientes con discapacidad moderada-grave tras un ictus incluidos en un programa de rehabilitacion multidisciplinar.Introduccion. Los ictus son causa frecuente de discapacidad en el adulto; sin embargo, la repercusion que los deficits que acontecen tras un ictus moderado-grave tiene sobre el grado de discapacidad final, asi como la respuesta de estos a programas de rehabilitacion, no se ha estudiado por completo. Pacientes y metodos. Se incluyeron 396 pacientes con Rankin modificado >= 3 despues de un ictus isquemico (n = 221) o hemorragico (n = 175). En todos los pacientes se evaluo su situacion cognitiva, conductual, emocional, motora y funcional. Todos los pacientes fueron incluidos en un programa de rehabilitacion multidisciplinar y reevaluados tras seis meses de tratamiento. Resultados. El riesgo de caida (escala de equilibrio de Berg < 45 en el 83,1% de la muestra) y los deficits funcionales (indice de Barthel < 75 en el 82,8% de la muestra) fueron los problemas mas prevalentes en el momento del ingreso, mientras que los conductuales lo fueron en el del alta (55,1% de la muestra). Los problemas emocionales fueron los que mas mejoraron, mientras que los conductuales fueron los que menos lo hicieron. El nivel de discapacidad global mejoro tras el tratamiento, aunque solo un 11% de los pacientes, especialmente los que tenian buena situacion cognitiva en el ingreso, lograron alcanzar una discapacidad leve. Conclusiones. Las consecuencias del ictus son multidimensionales. La afectacion de las distintas esferas y el patron de recuperacion son diferenciales, con predominio a largo plazo de los problemas conductuales.

25 Hydroxy Vitamin D Level, Bone Health, Vitamin D and Calcium Intake in Chilean Patients with Phenylketonuria and Hyperphenylalaninemias

Abstract It has been shown that there is a decrease in the concentrations of 25 hydroxyvitamin D (25-OHD) and bone mineral density (BMD) in patients with phenylketonuria (PKU) in their follow-up. Our objective was to determine concentrations of 25-OHD in subjects with PKU and hyperphenylalaninemia (HPA). Transversal analytical study considered three groups: G1-PKU with neonatal diagnosis and formula intake without Phe; G2-HPA, without specific treatment and G3-C control group. Sixteen patients per group (aged 6-23) were included. Levels of 25-OHD, lumbar spine (L2-L4), femur and total BMD, intact parathormone (PTH) and vitamin D (VitD) and calcium intake were calculated. The Kruskal-Wallis statistical test was applied (p-value<0,05). Significant differences were detected in concentrations of 25-OHD between G1-PKU and G2-HPA (38.9 ng/mL; 28 ng/mL, respectively) (NV: >30 ng/mL). G1-PKU had a higher intake of VitD, with differences among groups. There were no significant differences among groups in relation to BMD and intact PTH. In conclusion, G1-PKU under treatment and with good adherence, does not present VitD deficiency and no BMD alterations are observed. In contrast, G2-HPA had a lower intake of VitD and decreased 25-OHD concentrations which could affect the bone architecture in the long term. Further studies on the G2-HPA are suggested.

Reflejo olivococlear contralateral y su relación con ansiedad y calidad de vida en pacientes con tinnitus

Resumen Introducción: La presencia de tinnitus se asocia a un incremento del nivel de ansiedad y empeoramiento de la calidad de vida, sin embargo, aún no existe claridad de si el sistema eferente auditivo podría influir en estas relaciones. Objetivo: Determinar si las amplitudes de las emisiones otoacústicas por producto de distorsión (EOAPD) y el efecto supresor del reflejo olivococlear gatillado con ruido contralateral (ROC) se asocian al grado del impacto psicoemocional y nivel de ansiedad en pacientes con tinnitus. Material y Método: Se evaluaron las amplitudes de EOAPD y magnitud del ROC para cada oído de manera independiente en una cohorte de 32 sujetos tinnitus y 26 controles, cuyos valores fueron correlacionados con State-Trait Anxiety Inventory (STAI) y Tinnitus Handicap Inventory (THI). Resultados: Los pacientes con tinnitus tuvieron una correlación significativa entre la magnitud del ROC del oído izquierdo y los puntajes en las pruebas de STAI y THI. Conclusión: Una mayor carga de ansiedad y peor calidad de vida en sujetos con tinnitus puede estar asociada con un empeoramiento del efecto supresor del ROC de la vía eferente auditiva.

Abstract Introduction: Tinnitus is associated with an increase in the degree of anxiety and with worse quality of life. However, whether there are relations between the function of the auditory efferent system and anxiety and tinnitus distress levels is not known. Aim: To determine possible associations between the distortion product otoacoustic emission (DPOAE) amplitudes and the suppressing effect of the olivo-cochlear reflex (OCR) with anxiety and psycho-emotional impact in tinnitus. Material and Method: DPOAE amplitudes and OCR strength were evaluated for each ear independently in a cohort of 32 tinnitus and 26 controls, whose values were correlated with the State-Trait Anxiety Inventory (STAI) and Tinnitus Handicap Inventory (THI). Results: A significant correlation of STAI and THI scales with the OCR strength measured in the left ear was found in subjects with tinnitus. Conclusion: A higher anxiety load and worse quality of life in subjects with tinnitus may be associated with an impaired olivocochlear reflex suppressing effect.

Daños de salud respiratoria en comunas expuestas a centrales termoeléctricas a carbón en el norte de Chile: análisis de datos secundarios / Respiratory health damage in communes exposed to coal-fired power plants in northern Chile

INTRODUCCIÓN: En Chile, el funcionamiento de las Centrales Termoeléctricas de Carbón (CTEC) representan un problema de salud pública debido a las consecuencias sanitarias que tienen en la población. Se han notificado daños en el sistema respiratorio. Materiales y MÉTODOS: Se realizó un estudio ecológico, para evaluar los egresos hospitalarios de las personas que viven en las ciudades donde operan las CTEC (Tocopilla y Huasco), se comparó con una ciudad de control sin CTEC (Caldera), las comunas evaluadas tienen condiciones sociodemográficas similares. Se calcularon las tasas de morbilidad y tasas de morbilidad estandarizadas (SMR). RESULTADOS: La tasa de morbilidad por enfermedades respiratorias en Tocopilla (2016) fue de 152,5 por 10.000 habitantes (habs) y para Huasco es de 135,2 por 10.000 habs. En la ciudad control, Caldera, la tasa es de 40,9 por 10.000 habs. Además, los habitantes de Tocopilla tienen 2,42 más riesgo de padecer bronquitis o bronquiolitis, 90% más riesgo de presentar enfermedades crónicas de las vías respiratorias bajas y 2,14 veces más riesgo de enfermar por asma. En Huasco, la población tiene 2,49 veces más riesgo de padecer enfermedades de las vías respiratorias inferiores con respecto a la región y 3,19 veces más riesgo de presentar asma. CONCLUSIONES: El asma y la bronquitis, son las patologías que mostraron mayores riesgos en las ciudades de Tocopilla y Huasco. Nuestros hallazgos son similares a otras investigaciones realizadas en comunidades expuestas a centrales termoeléctricas de carbón. Es necesario tomar medidas urgentes para proteger la salud de la población.

INTRODUCTION: In Chile, coal-fired power plants (CTEC) operate represents public health problems due to the health consequences for the population. Damage to the respiratory system is reported. MATERIALS AND METHODS: Ecological study to evaluate hospital discharges in people living in cities where CTEC operates (Tocopilla and Huasco) were compared to a control city without CTEC (Caldera), all of them with similar sociodemographic conditions. Morbidity rates and Standardized Morbidity Ratios (SMR) were calculated. RESULTS: The respiratory disease morbidity rate in Tocopilla (2016) was 152.5 per 10,000 inhabitants (habs) and for Huasco it is 135.2 per 10,000 inhabitants. In the control city, Caldera, the rate is 40.9 per 10,000 habs. In addition, the inhabitants of Tocopilla have a 2.42 times increased risk of bronchitis or bronchiolitis, 90% higher risk of chronic lower respiratory diseases and 2.14 times more risk of asthma sickness. In Huasco, the population is 2.49 times more at risk of lower respiratory diseases compared to the region and 3.19 times more at risk of asthma. CONCLUSIONS: Asthma and bronchitis are the pathologies that showed the greatest risks in the cities of Tocopilla and Huasco. Our findings are similar to other research conducted in communities exposed to coal-fired power plants. Urgent action is needed to protect the health of the population.

[Effectiveness of a ketogenic diet in children with refractory epilepsy: a systematic review]. / Efectividad de la dieta cetogenica en niños con epilepsia refractaria: revision sistematica.

INTRODUCTION: Epilepsy is a brain disorder that affects both children and adults. From the 1920s the ketogenic diet has gained prestige as another treatment option for patients with refractory epilepsy. SUBJECTS AND METHODS: A summary of the evidence will be made through a systematic review of randomized clinical trials that have compared a single ketogenic diet with other diet for the management of these patients. AIM: To determine the effectiveness of the ketogenic diet in reducing episodes of seizures in patients with refractory epilepsy. The search strategy included randomized controlled trials and controlled clinical trials. Databases used were Medline, LILACS, Central and CINAHL. RESULTS: Six articles that met our elegibility criteria. CONCLUSIONS: There is limited evidence that the ketogenic diet compared to the medium-chain triglyceride diet is more effective in reducing the frequency of seizures. There is also moderate evidence that classical ketogenic diet compared to the gradual diet (2.5:1 and 3:1) is more effective in reducing seizures. There is moderate evidence that classical ketogenic diet compared to Atkins diet is more effective in reducing the frequency of seizure. The decision to apply this type of diet should also be based on costs, preferences and safety of treatment. It should also take into account the likelihood that studies have indexing problems have been left out of the review.

TITLE: Efectividad de la dieta cetogenica en niños con epilepsia refractaria: revision sistematica.Introduccion. La epilepsia es una patologia cerebral que afecta tanto a niños como a adultos. Desde los años veinte, la dieta cetogenica ha ganado prestigio como otra opcion de tratamiento en pacientes con epilepsia refractaria. Sujetos y metodos. Se realiza una sintesis de la evidencia a traves de una revision sistematica de ensayos clinicos aleatorizados que hayan comparado una dieta cetogenica sola con otros tipos de dieta para el tratamiento de estos pacientes. Objetivo. Determinar la efectividad de la dieta cetogenica en la disminucion de los episodios de convulsiones en pacientes con epilepsia refractaria. La estrategia de busqueda incluyo ensayos clinicos aleatorizados y ensayos clinicos controlados. Las bases de datos usadas fueron: Medline, LILACS, Central y CINAHL. Resultados. Se obtuvieron seis articulos que cumplian con los criterios de elegibilidad. Conclusiones. Existe evidencia limitada de que la dieta cetogenica en comparacion con la dieta de trigliceridos de cadena media es mas efectiva en disminuir la frecuencia de las convulsiones. Existe evidencia moderada de que la dieta cetogenica clasica en comparacion con la dieta gradual (2,5:1 y 3:1) es mas efectiva para disminuir las crisis epilepticas. Existe evidencia moderada de que la dieta cetogenica clasica en comparacion con la dieta Atkins es mas efectiva para disminuir la frecuencia de convulsiones en tres meses. La decision de aplicar este tipo de dietas tambien debe basarse en costes, preferencias y seguridad del tratamiento. Ademas, debe considerarse la probabilidad de que algunos estudios, por problemas de indizacion, hayan quedado fuera de la revision.

Development of fly ash boards with thermal, acoustic and fire insulation properties.

This paper presents an experimental analysis on a new board composed of gypsum and fly ashes from coal combustion, which are mutually compatible. Physical and mechanical properties, sound absorption coefficient, thermal properties and leaching test have been obtained. The mechanical properties showed similar values to other commercial products. As far as the acoustic insulation characteristics are concerned, sound absorption coefficients of 0.3 and 0.8 were found. The board presents a low thermal conductivity and a fire resistance higher than 50 min (for 4 cm of thickness). The leaching of trace elements was below the leaching limit values. These boards can be considered as suitable to be used in building applications as partitions.

[Ventricular fibrillation and myocarditis]. / Fibrilación ventricular y miocarditis.

We report a case of ventricular fibrillation with subacute myocarditis as the only underlying pathological abnormality in a 9-year-old child. The patient died suddenly after a follow-up of 13 years, despite the apparent control of the arrhythmia.

[Madopar: more than 20 years]. / Más de 20 años de Madopar.

OBJECTIVE: To review the main landmarks which led to the introduction of levadopa in the the treatment of Parkinson's disease and the impact of levadopatherapy. DEVELOPMENT: The introduction of levadopa was based on the results of basic scientific investigations in neurochemistry and neuropharmacology. In 1959 the possibility of dopamine being a neurotransmissor, and the role it plays in motor control, had been discovered. In 1960, Hornykiewiez and Ehringer published a paper on the existence of a marked deficit of dopamine in the caudate nucleus and putamen of patients with Parkinson's disease. Almost simultaneously, Birkmayer and Barbeau treated their patients with levadopa for the first time. However, levadopa was not introduced into clinical practice until 1967 and 1969 when Cotzias published papers establishing the principles of levadopatherapy as we now know it. Introduction of levadopa produced a markedly beneficial effect on the course and mortality of Parkinson's disease. However, it was soon seen that progression of the disease was not halted and that undesirable side effects appeared in patients on long-term treatment. This has led to the development of strategies to prolong the beneficial effects of levadopa and minimize its side effects. CONCLUSION: More than 25 years after the introduction of levadopatherapy, it is still the mainstay of the treatment of Parkinson's disease, in combination with other medical and surgical treatment. Definitive treatment, however, will have to wait until the cause of this illness is fully understood.

[HIV myelopathy as the presenting symptom of acquired immunodeficiency syndrome]. / Mielopatía por VIH como síntoma inicial del síndrome de inmunodeficiencia adquirida.

INTRODUCTION: Spinal lesions in the acquired immunodeficiency syndrome (AIDS) occur in 22% of all neurological complications, although their occurrence as the first sign of the disease is very uncommon. First place amongst the myelopathies described as associated with HIV is taken by vacuolar myelopathy, followed by the myelites. CLINICAL CASE: We studied a 65 year old homosexual man who had previously been free of symptoms and signs of HIV infection. He was seen for progressive paraparesia which had begun some days previously, followed by altered sense of position and of vibration. Complementary tests showed that the patient was a carrier of HIV antibodies in high titre (P-24) with a high viral load of 907 x 1,000 copies RNA/ml. Testing with evoked potentials showed changes compatible with involvement of the sensory pathways of the spinal cord. After treatment with dexamethasone there was obvious improvement with partial recovery of his symptoms. CONCLUSIONS: The neurological condition described was compatible with vacuolar type myelopathy due to HIV, appearing in the initial stages of the illness and coinciding with a marked increase in the viraemia. Although necropsy is necessary for confirmation of the diagnosis, more and more evidence is being found on which to base clinical suspicion. We discuss various hypotheses regarding possible pathogenic mechanisms arising in these circumstances.

[Carcinomatosis of the choroid plexus: clinical case and necropsy findings]. / Carcinomatosis de plexos coroideos: caso clínco y hallazgos necrópsicos.

INTRODUCTION: Carcinomas of the choroid plexus are a rare malignant variety of papillary tumours which originate in the choroid plexus. Their occurrence in adults has been questioned because of the difficulty in differentiating them from the metastases of adenocarcinomas. CLINICAL CASE AND CONCLUSIONS: We present the case of a 57 year old man with a rapidly progressive illness characterized by disorientation, behaviour changes and amnesia, progressive deterioration of the level of consciousness until he was in deep coma and died (all within one month). There was no clinical evidence of the presence of a primary extra-cranial tumour. On magnetic resonance there was obliteration of the ventricular system with a protein material and thickening and increased marking of the ependyma walls, compatible with ventriculitis. Necropsy, limited to the skull, showed the presence of a malignant infiltrating tumour with papillary morphology, which affected the choroid plexuses of the whole ventricular system, infiltrated the adjacent nervous tissue and extended to the leptomeninges. These findings suggest a differential diagnosis between carcinoma of the choroid plexus and metastatic meningeal carcinoma.

Tinnitus: una patología cerebral / Tinnitus: a brain pathology

RESUMEN El tinnitus es un síntoma caracterizado por la percepción de un sonido en ausencia de un estímulo externo. Si bien su fisiopatología puede involucrar una alteración a nivel del funcionamiento del oído interno, la percepción de éste y el grado de molestias asociadas dependen de modificaciones de redes cerebrales cognitivas y emocionales. En la presente revisión, se abordan los cambios que existen a nivel coclear, de tronco encefálico, tálamo y la extensa red cerebral que dan cuenta del tinnitus, discutiendo como esta nueva conceptualización tiene importantes implicancias clínicas, permitiendo una mejor comprensión de los síntomas asociados al tinnitus, sus comorbilidades, y el desarrollo de nuevas estrategias terapéuticas.

ABSTRACT Tinnitus is a symptom characterized by the perception of a sound without an external stimulus. Although the pathophysiology of tinnitus initially involves an alteration of the inner ear function, the perception of it and the degree of distress associated with it depends on changes in cognitive and emotional brain networks. In this article, we review the changes that exist at the cochlea, brainstem, thalamus and a widespread cerebral networks that account for tinnitus, discussing how this new conceptualization has significant clinical implications and allows a better understanding of the symptoms associated with tinnitus, its co-morbidities, and how this view has allowed the development of new therapies.