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The development of metabolic diseases is linked to the gut microbiota. A cross-sectional study involving 45 children (6 to 12 years old) was conducted to investigate the relationship between gut microbiota and childhood obesity. Anthropometric and metabolic measurements, food-frequency questionnaires (FFQs), and feces samples were obtained. Using the body mass index (BMI) z-score, we categorized each participant as normal weight (NW), or overweight and obese (OWOB). We determined 2 dietary profiles: one with complex carbohydrates and proteins (pattern 1), and the other with saturated fat and simple carbohydrates (pattern 2). The microbial taxonomic diversity and metabolic capacity were determined using shotgun metagenomics. We found differences between both BMI groups diversity. Taxa contributing to this difference, included Eubacterium sp., Faecalibacterium prausnitzii, Dialister, Monoglobus pectinilyticus, Bifidobacterium pseudocatenulatum, Intestinibacter bartlettii, Bacteroides intestinalis, Bacteroides uniformis, and Methanobrevibacter smithii. Metabolic capacity differences found between NW and OWOB, included the amino acid biosynthesis pathway, the cofactor, carrier, and vitamin biosynthesis pathway, the nucleoside and nucleotide biosynthesis and degradation pathways, the carbohydrate-sugar degradation pathway, and the amine and polyamine biosynthesis pathway. We found significant associations between taxa such as Ruminococcus, Mitsuokella multacida, Klebsiella variicola, and Citrobacter spp., metabolic pathways with the anthropometric, metabolic, and dietary data. We also found the microbiome's lipooligosaccharide (LOS) category as differentially abundant between BMI groups. Metabolic variations emerge during childhood as a result of complex nutritional and microbial interactions, which should be explained in order to prevent metabolic illnesses in adolescence and maturity. IMPORTANCE The alteration of gut microbiome composition has been commonly observed in diseases involving inflammation, such as obesity and metabolic impairment. Inflammatory host response in the gut can be a consequence of dietary driven dysbiosis. This response is conducive to blooms of particular bacterial species, adequate to survive in an inflammatory environment by means of genetical capability of utilizing alternative nutrients. Understanding the genomic and metabolic contribution of microbiota to inflammation, including virulence factor prevalence and functional potential, will contribute to identifying modifiable early life exposures and preventive strategies associated with obesity risk in childhood.

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If a granular material is poured from above on a horizontal surface between two parallel, vertical plates, a sand heap grows in time. For small piles, the grains flow smoothly downhill, but after a critical pile size X_{c}, the flow becomes intermittent: sudden avalanches slide downhill from the apex to the base, followed by an "uphill front" that slowly climbs up, until a new downhill avalanche interrupts the process. By means of experiments, controlling the distance between the apex of the sandpile and the container feeding it from above, we show that X_{c} grows linearly with the input flux, but scales as the square root of the feeding height. We explain these facts from a phenomenological model based on the experimental observation that the flowing granular phase forms a "wedge" on top of the static one, differently from the case of stationary heaps. Moreover, we demonstrate that our controlled experiments allow to predict the value of X_{c} for the common situation in which the feeding height decreases as the pile increases in size.

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We study the behavior of cylindrical objects as they sink into a dry granular bed fluidized due to lateral oscillations. Somewhat unexpectedly, we have found that, within a large range of lateral shaking powers, cylinders with flat bottoms sink vertically, while those with a "foundation" consisting of a shallow ring attached to their bottom, tilt besides sinking. The latter scenario seems to dominate independently from the nature of the foundation when strong enough lateral vibrations are applied. We are able to explain the observed behavior by quasi-2D numerical simulations, which also demonstrate the influence of the intruder's aspect ratio. The vertical sink dynamics is explained with the help of a Newtonian equation of motion for the intruder. Our findings may shed light on the behavior of buildings and other manmade structures during earthquakes.

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La apendicitis aguda retrocecal perforada puede dar lugar a un absceso retroperitoneal. Presentamos el caso de un paciente varón de 66 años, obeso y diabético, que acudió por dolor y tumoración lumbar, y antecedente previo de dolor abdominal. Se realiza una tomografía donde se evidencia un absceso retroperitoneal con compromiso de partes blandas, y bolsa escrotal derecha. Se ingresa a sala de operaciones y se evidencia un apéndice retrocecal digerida en su extremo distal, evidenciando salida de pus al aperturar retroperitoneo y realizar una incisión lumbar e inguinal derechas. El paciente recibió antibióticoterapia y curaciones, y tuvo una buena evolución. El absceso retroperitoneal secundario a apendicitis aguda es una infección quirúrgica rara y grave, y que la misma ocasione una fascitis necrotizante es excepcional. Por lo que debe incluirse dentro de las posibilidades diagnósticas en todo paciente inmunosuprimido, con dolor lumbar y antecedente de dolor abdominal; requiriendo inicialmente una tomografía.

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RESUMEN Los trastornos pancreáticos, las pancreatitis agudas de etiología biliar son infrecuentes en pediatría y más aún los pseudoquistes pancreáticos, los cuales son colecciones líquidas rodeadas por una cápsula fibrosa sin epitelio, generalmente secundario a una pancreatitis aguda. Presentamos el caso de una paciente femenina de 14 años, con antecedente de pancreatitis aguda de origen biliar hace 10 meses, que presenta dolor abdominal y una masa palpable en epigastrio. Se realizaron estudios imagenológicos, confirmando el diagnóstico de pseudoquiste pancreático y colelitiasis. Se optó por las bondades técnicas y estéticas de la laparoscopía, para esta población. Por lo cual, se realizó una cistogastroanastomosis y colecistectomía laparoscópica, con una evolución favorable. Nosotros reafirmamos que esta técnica, es un método seguro y efectivo, para el manejo de esta patología en pacientes pediátricos, y debería considerarse como primera opción, al no contar con procedimientos endoscópicos. Siendo este, el primer reporte en nuestro medio.

ABSTRACT The pancreatic disorders, as acute pancreatitis, of biliary etiology are rare in pediatrics, even more the pancreatic pseudocysts. They are liquid collections surrounded of a fibrous capsule without epithelium, secondary to acute pancreatitis. We present the case of a 14-year-old female patient with a history of acute pancreatitis because of biliary etiology, 10 months prior. She complained of intermittent abdominal pain and a palpable mass in the epigastrium. The Imaging studies showed a pancreatic pseudocyst and cholelithiasis. The laparoscopy was chosen because the technical and esthetic benefits for this population. Therefore, a laparoscopic cystogastro-ostomy-anastomosis and cholecystectomy were performed, with good progress. We affirm this technique is a safe and effective method for the management of this pathology in pediatric patients, and it should be considered as the first option in case endoscopic procedures are not available. This is the first report in our settings.

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Abstract Nowadays, the experiments related to High Energy Physics and others fields demand the use of detectors with greater radiation resistance, and the novel material GaAs:Cr has demonstrated excellent radiation hardness compared with other semiconductors. On the basis of evidence obtained in the JINR experiment with the use of 22 MeV electrons beam generated by the LINAC-800 accelerator, an analysis of electron radiation effects on GaAs:Cr and Si detectors is presented. The measured I-V characteristics showed a dark current increase with dose, and an asymmetry between the two branches of behaviors for all detectors. Analyzing the MIP spectra and CCE dose dependence measurements a deterioration process of detectors collection capacity with dose increase was found, although behaviors are somewhat different according to the detector type. The detailed explanation of these effects from the microscopic point of view appears in the text, and are generally linked to the generation of atomic displacement, vacancies and other radiation defects, modifying the energy levels structure of the target material. These changes affect the lifetime and concentration of the charge carriers, and other characteristics of the target material.

Resumen Actualmente, los experimentos relacionados con la física de altas energías y otros campos, demandan el uso de detectores con mayor resistencia a las radiaciones y el novedoso material GaAs:Cr ha demostrado poseer una excelente fortaleza comparado con otros semiconductores. En base a las evidencias obtenidas en el experimento del IUIN con el uso de un haz de electrones de 22 MeV generado por el acelerador LINAC-800, se presenta un análisis de los efectos de la radiación en detectores de Si y GaAs:Cr. Las características I-V medidas mostraron un incremento de la corriente de fuga con la dosis y una asimetría entre las dos ramas de estos comportamientos para todos los detectores. Analizando las mediciones de los espectros MIP y la dependencia de la CCE con la dosis, fue encontrado un proceso de deterioro de la capacidad de detección de los detectores con el aumento de la dosis, sin embargo, los comportamientos son diferentes de acuerdo al tipo de detector. La explicación detallada de estos efectos desde el punto de vista microscópico aparece en el texto, los cuales están relacionados generalmente con la generación de desplazamientos atómicos, vacancias y otros defectos producto de la radiación, modificando la estructura de los niveles energéticos en el material sensor. Estos cambios afectan el tiempo de vida y la concentración de los portadores de carga, así como otras características del material.

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BACKGROUND: Childhood obesity is a serious public health problem in Mexico. Adult gut microbiota composition has been linked to obesity, but few studies have addressed the role of gut microbiota in childhood obesity. OBJECTIVES: The aim of this study is to compare gut microbiota composition in obese and normal-weight children and to associate gut microbiota profiles with amino acid serum levels and obesity-related metabolic traits. METHODS: Microbial taxa relative abundance was determined by 16S rRNA sequencing in 67 normal-weight and 71 obese children aged 6-12 years. Serum amino acid levels were measured by mass spectrometry. Associations between microbiota composition, metabolic parameters and amino acid serum levels were tested. RESULTS: No significant differences in phyla abundances or Firmicutes/Bacteroidetes ratios were observed between normal-weight and obese children. However, Bacteroides eggerthii abundance was significantly higher in obese children and correlated positively with body fat percentage and negatively with insoluble fibre intake. Additionally, Bacteroides plebeius and unclassified Christensenellaceae abundances were significantly higher in normal-weight children. Abundance of both these species correlated negatively with phenylalanine serum levels, a metabolite also found to be associated with obesity in Mexican children. CONCLUSIONS: The study identified bacterial species associated with obesity, metabolic complications and amino acid serum levels in Mexican children.

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The software RCB-arsenic was developed previously to simulate the metalloid behavior in a constructed wetland (CW). The model simulates water flow and reactive transport by contemplating the major processes of arsenic (As) retention inside of CW. The objective of this study was to validate the RCB-arsenic model by simulating the behavior of horizontal flow CW for As removal from water. The model validation was made using data from a 122-day experiment. Two CWs prototypes were used: one planted with Eleocharis macrostachya (CW_planted) and another one unplanted (CW_unplanted) as a control. The prototypes were fed with synthetic water prepared using well water and sodium arsenite (NaAsO2). In the RCB-arsenic model, a CW prototype was represented using a 2D mesh sized in accordance with the experiment. For simulation of As retention in CW, data addition was established in two stages that considered the mechanisms in the system: (1) aqueous complexation, precipitation/dissolution, and adsorption on granular media and (2) retention by plants: uptake (absorption) and rhizofiltration (adsorption). Simulation of As outlet (µg/L) in stage_1 was compared with CW_unplanted; the experimental mean was 40.79 ± 7.76 and the simulated 39.96 ± 6.32. As concentration (µg/L) in stage_2 was compared with CW_planted, the experimental mean was 9.34 ± 4.80 and the simulated 5.14 ± 0.72. The mass-balance simulation and experiment at 122 days of operation had a similar As retention rate (94 and 91%). The calibrated model RCB-arsenic adequately simulated the As retention in a CW; therefore, it constitutes a powerful tool of design.

Assuntos

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We study how a magnetic bead bounces onto a horizontal diamagnetic conducting plane. The bead, falling down by gravity from a certain height, produces an Eddy current that creates a repelling force. For low velocities the bead is trapped by the surface, for intermediate ones it escapes. In such a case the induced current changes its sign, and so does the force. The balance between diamagnetic and viscoelastic interactions determines the bouncing dynamics. We find experimentally the restitution coefficient as a function of the impact speed of the bead and develop, taking into account simple energetic considerations, a model able to reproduce our findings.

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Thick granular flows are essential to many natural and industrial phenomena. Experimentally, it has been well established that the grain velocity profile is linear from the free surface to a certain depth, after which it decreases exponentially in the so-called "creep region". In this paper we obtain an exponential velocity profile based on the force balance of a grain near a wall, where the Janssen effect and the non-locality of interactions between grains are considered. When experimental parameters such as flow angles and friction coefficients are introduced in our model, it is able to reproduce experimental creep velocity profiles previously reported in the literature.