Intestinal volvulus in the pump twin of a twin reversed arterial perfusion (TRAP) sequence after laser therapy at 18 weeks: a case report

Background: Twin reversed arterial perfusion sequence is a rare and potentially lethal condition affecting approximately 1% of monochorionic twin pregnancies and 1 in 35,000 pregnancies overall. An apparently normal (pump) twin perfuses its severely malformed cotwin with deoxygenated blood via retrograde flow in direct arterioarterial anastomoses between the umbilical arteries of each twin. Fetal intestinal volvulus is a rare condition usually manifesting after birth. We report a unique case of twin reversed arterial perfusion sequence in association with intestinal volvulus in the surviving pump twin. Case presentation: A 32-year-old Hispanic primigravida was referred to our clinic after a fetoscopy procedure of laser photocoagulation of anastomoses at 18 weeks of gestation. Follow up scans in the ex-pump twin revealed dilated bowel loops and a typical “whirlpool sign” at 26 weeks of gestation, and intrauterine intestinal volvulus was suspected. At 29 weeks of gestation, preterm premature rupture of membranes occurred, and an emergency cesarean section was performed. The newborn was diagnosed in the early neonatal period with intestinal perforation. The diagnosis was postnatally confirmed by surgery and histopathology. Conclusions: The type of fetal intervention and late gestational age of the procedure increase the risk of complications. This case alerts health providers to be vigilant in the follow-up of patients with complicated monochorionic pregnanciesBackground: Twin reversed arterial perfusion sequence is a rare and potentially lethal condition affecting approximately 1% of monochorionic twin pregnancies and 1 in 35,000 pregnancies overall. An apparently normal (pump) twin perfuses its severely malformed cotwin with deoxygenated blood via retrograde flow in direct arterioarterial anastomoses between the umbilical arteries of each twin. Fetal intestinal volvulus is a rare condition usually manifesting after birth. We report a unique case of twin reversed arterial perfusion sequence in association with intestinal volvulus in the surviving pump twin. Case presentation: A 32-year-old Hispanic primigravida was referred to our clinic after a fetoscopy procedure of laser photocoagulation of anastomoses at 18 weeks of gestation. Follow up scans in the ex-pump twin revealed dilated bowel loops and a typical “whirlpool sign” at 26 weeks of gestation, and intrauterine intestinal volvulus was suspected. At 29 weeks of gestation, preterm premature rupture of membranes occurred, and an emergency cesarean section was performed. The newborn was diagnosed in the early neonatal period with intestinal perforation. The diagnosis was postnatally confirmed by surgery and histopathology. Conclusions: The type of fetal intervention and late gestational age of the procedure increase the risk of complications. This case alerts health providers to be vigilant in the follow-up of patients with complicated monochorionic pregnancie

Kinetic analysis of biomass thermal decomposition applying a scheme of independent parallel reactions

El objetivo de este trabajo fue el análisis cinético de la descomposición térmica de cuatro biomasas lignocelulosicas procedentes de Brasil: madera de caixeta (Tabebuia cassinoides Lam.), cascarilla de arroz (Oryza sativa L.), bagazo y residuo de corte de la caña de azúcar (Saccharum officinarum L.). Los experimentos de descomposición térmica fueron llevados a cabo en un analizador termogravimétrico, utilizando tasas de calentamiento de 10 °C/min. El análisis cinético de la descomposición térmica de las biomasas fue realizado aplicando un esquema de tres reacciones paralelas independientes. Los resultados mostraron que el modelo se ajustó muy bien a los datos experimentales, y las energías de activación estuvieron entre 118-130 kJ/kmol, 200-215 kJ/kmol, y 100-150 kJ/kmol, para las reacciones modeladas de la hemicelulosa, celulosa, y lignina, respectivamente. También, fueron determinadas correlaciones entre el logaritmo del factor pre-exponencial y la energía de activación para cada reacción evaluada, y probadas con cada una de las biomasas analizadas. Finalmente, fue concluido que las correlaciones obtenidas pueden ser utilizadas para la obtención de los parámetros cinéticos de la descomposición térmica de diversas biomasas, contribuyendo con el proceso de modelado a través de la reducción del tiempo que se invierte en el proceso iterativo.The aim of this work was the kinetic analysis of the thermal decomposition of four Brazilian lignocellulosic biomasses: caixeta wood (Tabebuia cassinoides Lam.), rice husk (Oryza sativa L.), sugarcane bagasse and straw (Saccharum officinarum L.). The thermal decomposition experiments were carried out in a thermogravimetric analyzer using a heating rate of 10 °C/min. The kinetic analysis of the biomass thermal decomposition was carried out applying a scheme of three independent parallel reactions. The results showed that the model was in agreement with the experimental data, and the activation energies obtained were between 118-130 kJ/kmol, 200-215 kJ/kmol, and 100-150 kJ/kmol, for hemicelulose, cellulose and lignin modeled reactions, respectively. Also, were determined linear correlations between the logarithm of the pre-exponential factor and activation energy for each reaction evaluated, and tested in the biomasses analyzed. Finally, was concluded that the correlations obtained could be used for the determination of the kinetic parameters of the thermal decomposition of several biomasses, contributing to the modeling process by reducing the time invested in the iteration process.   &nbsp

Análisis cinético de la descomposición térmica de biomasas aplicando un esquema de reacciones paralelas independientes

The aim of this work was the kinetic analysis of the thermal decomposition of four Brazilian lignocellulosic biomasses: caixeta wood (Tabebuia cassinoides Lam.), rice husk (Oryza sativa L.), sugarcane bagasse and straw (Saccharum officinarum L.). The thermal decomposition experiments were carried out in a thermogravimetric analyzer using a heating rate of 10 °C/min. The kinetic analysis of the biomass thermal decomposition was carried out applying a scheme of three independent parallel reactions. The results showed that the model was in agreement with the experimental data, and the activation energies obtained were between 118-130 kJ/kmol, 200-215 kJ/kmol, and 100-150 kJ/kmol, for hemicelulose, cellulose and lignin modeled reactions, respectively. Also, were determined linear correlations between the logarithm of the pre-exponential factor and activation energy for each reaction evaluated, and tested in the biomasses analyzed. Finally, was concluded that the correlations obtained could be used for the determination of the kinetic parameters of the thermal decomposition of several biomasses, contributing to the modeling process by reducing the time invested in the iteration process.    El objetivo de este trabajo fue el análisis cinético de la descomposición térmica de cuatro biomasas lignocelulosicas procedentes de Brasil: madera de caixeta (Tabebuia cassinoides Lam.), cascarilla de arroz (Oryza sativa L.), bagazo y residuo de corte de la caña de azúcar (Saccharum officinarum L.). Los experimentos de descomposición térmica fueron llevados a cabo en un analizador termogravimétrico, utilizando tasas de calentamiento de 10 °C/min. El análisis cinético de la descomposición térmica de las biomasas fue realizado aplicando un esquema de tres reacciones paralelas independientes. Los resultados mostraron que el modelo se ajustó muy bien a los datos experimentales, y las energías de activación estuvieron entre 118-130 kJ/kmol, 200-215 kJ/kmol, y 100-150 kJ/kmol, para las reacciones modeladas de la hemicelulosa, celulosa, y lignina, respectivamente. También, fueron determinadas correlaciones entre el logaritmo del factor pre-exponencial y la energía de activación para cada reacción evaluada, y probadas con cada una de las biomasas analizadas. Finalmente, fue concluido que las correlaciones obtenidas pueden ser utilizadas para la obtención de los parámetros cinéticos de la descomposición térmica de diversas biomasas, contribuyendo con el proceso de modelado a través de la reducción del tiempo que se invierte en el proceso iterativo

Análisis cinético de la descomposición térmica de biomasas aplicando un esquema de reacciones paralelas independientes

The aim of this work was the kinetic analysis of the thermal decomposition of four Brazilian lignocellulosic biomasses: caixeta wood (Tabebuia cassinoides Lam.), rice husk (Oryza sativa L.), sugarcane bagasse and straw (Saccharum officinarum L.). The thermal decomposition experiments were carried out in a thermogravimetric analyzer using a heating rate of 10 °C/min. The kinetic analysis of the biomass thermal decomposition was carried out applying a scheme of three independent parallel reactions. The results showed that the model was in agreement with the experimental data, and the activation energies obtained were between 118-130 kJ/kmol, 200-215 kJ/kmol, and 100-150 kJ/kmol, for hemicelulose, cellulose and lignin modeled reactions, respectively. Also, were determined linear correlations between the logarithm of the pre-exponential factor and activation energy for each reaction evaluated, and tested in the biomasses analyzed. Finally, was concluded that the correlations obtained could be used for the determination of the kinetic parameters of the thermal decomposition of several biomasses, contributing to the modeling process by reducing the time invested in the iteration process.    El objetivo de este trabajo fue el análisis cinético de la descomposición térmica de cuatro biomasas lignocelulosicas procedentes de Brasil: madera de caixeta (Tabebuia cassinoides Lam.), cascarilla de arroz (Oryza sativa L.), bagazo y residuo de corte de la caña de azúcar (Saccharum officinarum L.). Los experimentos de descomposición térmica fueron llevados a cabo en un analizador termogravimétrico, utilizando tasas de calentamiento de 10 °C/min. El análisis cinético de la descomposición térmica de las biomasas fue realizado aplicando un esquema de tres reacciones paralelas independientes. Los resultados mostraron que el modelo se ajustó muy bien a los datos experimentales, y las energías de activación estuvieron entre 118-130 kJ/kmol, 200-215 kJ/kmol, y 100-150 kJ/kmol, para las reacciones modeladas de la hemicelulosa, celulosa, y lignina, respectivamente. También, fueron determinadas correlaciones entre el logaritmo del factor pre-exponencial y la energía de activación para cada reacción evaluada, y probadas con cada una de las biomasas analizadas. Finalmente, fue concluido que las correlaciones obtenidas pueden ser utilizadas para la obtención de los parámetros cinéticos de la descomposición térmica de diversas biomasas, contribuyendo con el proceso de modelado a través de la reducción del tiempo que se invierte en el proceso iterativo

Chemical and nano-mineralogical study for determining potential uses of legal Colombian gold mine sludge: Experimental evidence

The present study is focused on the chemical and nano-mineralogical characterization of sludge from gold mine activities, in order to put forward diverse solution alternatives, where lack of knowledge has been found. The sample was collected from “La Estrella” mine of Suarez, located in Department of Cauca, south-west Colombia. The sludge micro-structure and chemical composition were analyzed using a high resolution transmission electron microscopy (HR-TEM) equipped with a dispersive X-ray detector (EDS). X-ray diffraction technique was employed to identify the mineralogical phases present in the sludge. Additional mineralogical characterization was done by using RAMAN spectroscopy. Main findings points to its potential to be used as a fertilizer, this is why, mine sludge contains macronutrients such as P, Ca and S, together with micronutrients like Cu. However, the presence of goethite could decrease the mobilization of nutrients to soils, thus additional alternatives, for instance, a mixture with humus or another material containing Humic Acids should be done, in order to minimizing its retention effect. Additionally, another possible uses to explore could be as construction and ceramic material or in the wastewater treatment for nutrient retention and organic material removal. Rutile (TiO2 nanoparticles) particles have been also detected, what could cause health concern due to its nanoparticle toxic character, mainly during gold extraction process

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Isoconversional Kinetic Study Of The Thermal Decomposition Of Sugarcane Straw For Thermal Conversion Processes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The aim of this work was investigate the kinetics of the thermal decomposition reaction of sugarcane straw. The thermal decomposition experiments were conducted at four heating rates (1.25, 2.5, 5 and 10 degrees C/min) in a thermogravimetric analyzer using nitrogen as inert atmosphere. The kinetic analysis was carried out applying the isoconversional method of Friedman, and the activation energies obtained varied from 154.1 kJ/mol to 177.8 kJ/mol. The reaction model was determined through master plots, corresponding to a two-dimensional diffusion. The pre-exponential factor of 1.82 * 10(9) s(-1) was determined by linearization of the conversion rate equation as a function of the inverse of absolute temperature, concerning to activation energy of 149.7 kJ/mol, which are in the order of magnitude for biomass thermal decomposition reported in literature. Finally, the theoretical and experimental conversion data showed a very good agreement, indicating that these results could be used for future process modeling involving sugarcane straw. (C) 2015 Elsevier Ltd. All rights reserved.196136144Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

An Empirical Model To Obtain The Kinetic Parameters Of Lignocellulosic Biomass Pyrolysis In An Independent Parallel Reactions Scheme

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The aim of this work was to propose a new analysis procedure to obtain the kinetic parameters of lignocellulosic biomass pyrolysis assuming first order reactions in independent parallel scheme using sugarcane straw as case study. The thermogravimetric experiments were carried out using heating rates between 1.25 degrees C/min and 10 degrees C/min. Firstly, considering 700 different scenarios were obtained correlations between pre-exponential factor and activation energy from simulations of a first order global reaction. In these correlations only three experimental parameters are strictly necessary such as heating rate, peak temperature and peak conversion rate. Two approaches were proposed to apply the correlations in an independent parallel reactions scheme in order to obtain the kinetic parameters of lignocellulosic biomass pyrolysis. The results obtained with both approaches presented a good agreement between experimental and modeled data. Therefore, the correlations proposed will help in the kinetic parameters determination providing reliable results. (C) 2015 Published by Elsevier B.V.140222230Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Análisis cinético de la descomposición térmica de biomasas aplicando un esquema de reacciones paralelas independientes

The aim of this work was the kinetic analysis of the thermal decomposition of four Brazilian lignocellulosic biomasses: caixeta wood (Tabebuia cassinoides Lam.), rice husk (Oryza sativa L.), sugarcane bagasse and straw (Saccharum officinarum L.). The thermal decomposition experiments were carried out in a thermogravimetric analyzer using a heating rate of 10 °C/min. The kinetic analysis of the biomass thermal decomposition was carried out applying a scheme of three independent parallel reactions. The results showed that the model was in agreement with the experimental data, and the activation energies obtained were between 118-130 kJ/kmol, 200-215 kJ/kmol, and 100-150 kJ/kmol, for hemicelulose, cellulose and lignin modeled reactions, respectively. Also, were determined linear correlations between the logarithm of the pre-exponential factor and activation energy for each reaction evaluated, and tested in the biomasses analyzed. Finally, was concluded that the correlations obtained could be used for the determination of the kinetic parameters of the thermal decomposition of several biomasses, contributing to the modeling process by reducing the time invested in the iteration process.    El objetivo de este trabajo fue el análisis cinético de la descomposición térmica de cuatro biomasas lignocelulosicas procedentes de Brasil: madera de caixeta (Tabebuia cassinoides Lam.), cascarilla de arroz (Oryza sativa L.), bagazo y residuo de corte de la caña de azúcar (Saccharum officinarum L.). Los experimentos de descomposición térmica fueron llevados a cabo en un analizador termogravimétrico, utilizando tasas de calentamiento de 10 °C/min. El análisis cinético de la descomposición térmica de las biomasas fue realizado aplicando un esquema de tres reacciones paralelas independientes. Los resultados mostraron que el modelo se ajustó muy bien a los datos experimentales, y las energías de activación estuvieron entre 118-130 kJ/kmol, 200-215 kJ/kmol, y 100-150 kJ/kmol, para las reacciones modeladas de la hemicelulosa, celulosa, y lignina, respectivamente. También, fueron determinadas correlaciones entre el logaritmo del factor pre-exponencial y la energía de activación para cada reacción evaluada, y probadas con cada una de las biomasas analizadas. Finalmente, fue concluido que las correlaciones obtenidas pueden ser utilizadas para la obtención de los parámetros cinéticos de la descomposición térmica de diversas biomasas, contribuyendo con el proceso de modelado a través de la reducción del tiempo que se invierte en el proceso iterativo