The role of microparticles on the shape and surface tension of static bubbles.

HYPOTHESIS: Surface tension is a critical parameter in bubbles and foams, yet it is difficult to assess when microparticles are attached at the interface. By considering the interaction force between an air-liquid interface and microparticles, modified equations for sessile bubble tensiometry can be derived to determine the surface tension and shape of static microparticle-laden bubbles. EXPERIMENTS: A modified sessile bubble method, in which the forces between microparticles and the air-liquid interface are considered, was developed and used to analyse the surface tension of bubbles fully coated by a monolayer of silica microparticles of different sizes. The results are compared to those obtained using classical sessile bubble tensiometry. The new method is also used to investigate the contours of particle-laden bubbles of varying particle radius and contact angle. FINDINGS: While the classical sessile bubble method overestimates the surface tension, results obtained using the modified sessile bubble method show that the surface tension of static microparticle-laden bubbles remains the same as that of uncoated bubbles, with no dependency on the particle size. The discrepancy is due to the fact that microparticles attached to the air-liquid interface deform a bubble in a similar way that changes in surface tension do for uncoated bubbles.

The pinch-off dynamics of bubbles coated by microparticles.

HYPOTHESIS: While the pinch-off dynamics of bubbles is known to be influenced by changes in surface tension, previous studies have only assessed changes due to liquid properties or surfactant effects at the air-liquid interface but not due to the presence of particles. The current study proposes that particles at the air-liquid interface play an important role in changing the surface tension and thus the pinch-off dynamics of particle-laden bubbles. EXPERIMENTS: High-speed photography was used to study the pinch-off dynamics of air bubbles coated by a monolayer of silica microparticles. The influence of bubble surface coverage and particle size classes on the bubble pinch-off dynamics were explored. FINDINGS: We identify that although the scaling exponent of the power law that governs the pinch-off of coated and uncoated bubbles is the same, the pinch-off dynamics is distinctly different when particles are present at the air-liquid interface due to a decrease in surface tension with time in the neck region. We suggest that the surface pressure generated by particle interaction reduces the pinch-off speed by reducing the apparent surface tension. We observe that the apparent surface tension is dependent on particle size but not on the percentage of bubble surface coated by particles.

Characterization of Ferroplasma acidiphilum growing in pure and mixed culture with Leptospirillum ferriphilum.

Biomining is defined as biotechnology for metal recovery from minerals, and is promoted by the concerted effort of a consortium of acidophile prokaryotes, comprised of members of the Bacteria and Archaea domains. Ferroplasma acidiphilum and Leptospirillum ferriphilum are the dominant species in extremely acid environments and have great use in bioleaching applications; however, the role of each species in this consortia is still a subject of research. The hypothesis of this work is that F. acidiphilum uses the organic matter secreted by L. ferriphilum for growth, maintaining low levels of organic compounds in the culture medium, preventing their toxic effects on L. ferriphilum. To test this hypothesis, a characterization of Ferroplasma acidiphilum strain BRL-115 was made with the objective of determining its optimal growth conditions. Subsequently, under the optimal conditions, L. ferriphilum and F. acidiphilum were tested growing in each other's supernatant, in order to define if there was exchange of metabolites between the species. With these results, a mixed culture in batch cyclic operation was performed to obtain main specific growth rates, which were used to evaluate a mixed metabolic model previously developed by our group. It was observed that F. acidiphilum, strain BRL-115 is a chemomixotrophic organism, and its growth is maximized with yeast extract at a concentration of 0.04% wt/vol. From the experiments of L. ferriphilum growing on F. acidiphilum supernatant and vice versa, it was observed that in both cases cell growth is favorably affected by the presence of the filtered medium of the other microorganism, proving a synergistic interaction between these species. Specific growth rates were obtained in cyclic batch operation of the mixed culture and were used as input data for a Flux Balance Analysis of the mixed metabolic model, obtaining a reasonable behavior of the metabolic fluxes and the system as a whole, therefore consolidating the model previously developed. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1390-1396, 2016.

Desafíos en el establecimiento de la alianza terapéutica con pacientes suicidas / Challenges in establishing the therapeutic alliance with suicidal patients

Desde la perspectiva del modelo intersubjetivo, se analiza y reflexiona, respecto a las dificultades y desafíos que como terapeutas debemos enfrentar en el establecimiento de la alianza terapéutica con pacientes suicidas.En el trabajo con pacientes suicidas nos encontramos con una primera etapa que se configura como un impasse y que, como tal, implica aspectos tanto del paciente como del terapeuta, cuya resolución es crucial para el desarrollo y pronóstico del proceso terapéutico que se intenta llevar a cabo.Durante la etapa inicial del tratamiento, por lo general, nos encontramos con un paciente disociado de sus estados emocionales, capaz de hablar de sí mismo, de su decisión de quitarse la vida, de su conducta y sus implicancias sin ningún afecto. Como terapeutas inevitablemente nos enfrentamos con el desafío de comprender y contener aspectos esenciales de la experiencia humana respecto al sentido de la vida, lo que nos lleva a revisar, cuestionar y reflexionar en torno a nuestro propio sentido vital, debiendo hacernos cargo y elaborar nuestra propia subjetividad, resultante de la interacción. El desafío apunta a la necesidad de sostener la tensión psicológica de un encuentro cargado de ambivalencia, de modo de favorecer el desarrollo y significado del proceso analítico. Con el objeto de ejemplificar lo señalado, en relación a este primer encuentro, se presentará una viñeta clínica.

This article analyzes and presents a discussion on the difficulties and challenges that we as therapists must face when establishing a therapeutic alliance with suicidal patients, from the perspective of the intersubjective model.Working with suicidal patients entails a first stage configured as an impasse, which involves aspects both of the patient and of the therapist, whose resolution is crucial for the development and prognosis of the therapeutic process. During the initial stage of the treatment, we generally encounter a patient who is dissociated from his/her emotional states and who are able to talk about themselves, their decision to take their own lives, and their conduct and its implications with no affect whatsoever. As therapists, we inevitably face the challenge of understanding and containing the essential aspects of human experience regarding the meaning of life, which makes us revise, question, and reflect on the meaning of our own lives. This requires that we process and take responsibility for our own subjectivity as a result of the therapeutic interaction. The challenge refers to the need to sustain the psychological tension of an encounter loaded with ambivalence, in order to foster the development and meaning of the analytical process. A clinical vignette will be presented in order to exemplify the above in connection with this first encounter.

Gastrointestinal stromal tumors (GISTs) of the colon.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. Although they may arise anywhere of GI tract, colonic presentation is infrequent. We report 2 new cases of colonic GISTs localized at descending and sigmoid colon. Endoscopic biopsies were diagnostic for GISTs and no distant metastasis were observed. Both cases underwent resective surgery as the only treatment. No recurrence was observed during the follow-up period. In this clinical note we review the diagnosis, management and therapeutical options in colonic GISTs, according to literature. KIT immunoreactivity is the base for diagnosis. Risk of malignancy is based on the primary tumor diameter and the mitotic count. Anatomic localization is not an independent prognostic factor. Surgery is the standard treatment for localized primary disease and imatinib is indicated if metastatic or unresectable GISTs.

Tumores del estroma gastrointestinal (GIST) del colon / No disponible

Los tumores del estroma gastrointestinal (GIST) son los tumores mesenquimales más comunes del tracto gastrointestinal (GI). Aunque pueden aparecer en cualquier localización del tracto GI, el colon no es una ubicación frecuente. Presentamos 2 nuevos casos de GIST de colon localizados en el colon descendente y el sigma. El diagnóstico histológico se obtuvo mediante biopsias endoscópicas. En ambos casos se realizó cirugía resectiva como único tratamiento. No se objetivó afectación metastásica en ningún caso. Tampoco se observó recurrencia durante el período de seguimiento. En esta nota clínica hemos revisado el diagnóstico, manejo y opciones terapéuticas en los GIST de colon. La inmunorreactividad para el c-kit es la clave para el diagnóstico. El riesgo de malignización se basa en el diámetro tumoral y el índice mitótico. La localización anatómica no parece ser un factor pronóstico independiente. La cirugía supone el tratamiento estándar en caso de enfermedad localizada, mientras que el imatinib está indicado en los GIST irresecables o con afectación metastásica(AU)

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. Although they may arise anywhere of GI tract, colonic presentation is infrequent. We report 2 new cases of colonic GISTs localized at descending and sigmoid colon. Endoscopic biopsies were diagnostic for GISTs and no distant metastasis were observed. Both cases underwent resective surgery as the only treatment. No recurrence was observed during the follow-up period. In this clinical note we review the diagnosis, management and therapeutical options in colonic GISTs, according to literature. KIT immunoreactivity is the base for diagnosis. Risk of malignancy is based on the primary tumor iameter and the mitotic count. Anatomic localization is not an independent prognostic factor. Surgery is the standard treatment for localized primary disease and imatinib is indicated if metastatic or unresectable GISTs(AU)

Tratamiento quirúrgico de la obesidad: ¿a quién?, ¿qué técnica?, ¿es necesario el seguimiento postoperatorio? / Surgical treatment: of obesity what patient?, what technique?, is postoperative follow-up mandatory?

La obesidad mórbida (índice de masa corporal igual o superior a 40 kg/m2) implica un riesgo elevado de morbimortalidad y suele ser resistente al tratamiento médico. El abordaje quirúrgico puede conseguir una pérdida de peso efectiva a largo plazo, con mejoría de las comorbilidades y de la calidad de vida, pero presenta el riesgo de que se produzcan complicaciones potencialmente graves, si bien constituye una opción válida en pacientes seleccionados con criterios de inclusión en un programa multidisciplinario protocolizado. Las técnicas quirúrgicas actuales pueden ser simples (restrictivas) o complejas, asociando derivación gástrica y/o malabsorción intestinal. En general, las técnicas complejas producen mejores resultados en cuanto a pérdida de peso, pero tienen mayor riesgo de que se produzcan deficiencias nutricionales, por lo que la elección del tipo de intervención debe individualizarse en función de la experiencia del equipo quirúrgico y de las características del paciente. El seguimiento postoperatorio es imprescindible, no sólo para detectar cuanto antes la aparición de complicaciones, sino para validar los resultados de la intervención. Deben valorarse la evolución de los índices ponderales, la mejoría de comorbilidades, la calidad de vida, los parámetros nutricionales y la aparición de complicaciones. Es necesaria una educación nutricional específica para facilitar la tolerancia digestiva y conseguir una buena adherencia al tratamiento (AU)

Extracción de ADN de uñas: alternativa rápida para la identificación de cadaveres / DNA extraction from nails: a fast alternative for corpses identification

Desde que en 1.994 llegó a nuestro Laboratorio el primer caso con fines identificativos en el que la muestra indubitada consistía en tejido ungueal, comenzamos los ensayos tendentes a la obtención de ADN de las mismas. El trabajo se enfocó, en principio, hacia la obtención de un método eficaz para la extracción de una cantidad de ADN que fuera suficiente para realizar análisis genéticos vía PCR. Desde entonces, y tras sucesivas modificaciones de la técnica, tendentes siempre hacia una simplicación de la misma, los resultados han sido siempre positivos, logrando la amplificación de ADN para los marcadores utilizados en cada momento (AU)

One year of Lamivudine therapy for portuguese patients with chronic hepatitis B.

OBJECTIVE: To assess the efficacy of lamivudine treatment on hepatitis B e antigen (HBeAg) and/or hepatitis B surface antigen (HBsAg) seroconversion, on other virological and serological markers of response including hepatitis B virus (HBV) DNA and serum aminotransferases, and the safety of lamivudine treatment in hepatitis B patients. PATIENTS: This phase III open-label study evaluated the virological and biochemical response to lamivudine in 70 Portuguese patients with HBeAg positive chronic hepatitis B. Patients were treated with lamivudine 100mg once daily for 12 months. METHODS: Antiviral activity was assessed by measuring alanine aminotransferase (ALT)/aspartate aminotransferase (AST) levels at all protocol visits, and hepatitis B serology and HBV DNA were performed at baseline and at month 12 visits. Evaluation of safety and tolerance was based on clinical adverse events and laboratory analyses. RESULTS: The primary endpoint was virological response at month 12, defined as loss of detectable HBeAg from serum with a reduction of HBV DNA to undetectable levels, and this was observed in 19/69 (27.5%) of patients. Almost half of the patients were HBV DNA negative by this time. Mean ALT values decreased steadily during treatment and by 12 months 61% of patients had values within the normal range. HBeAg seroconversion (HBeAg negative, HBeAb positive) was achieved in 27.9% of patients by 12 months, although all patients remained HBsAg positive. CONCLUSION: Lamivudine was well tolerated and the incidence of adverse events was similar to those reported in previous studies. Lamivudine treatment resulted in virological and biochemical improvements in HBeAg positive chronic hepatitis B patients, with HBeAg seroconversion in one-third of patients.

Assembly of Saccharomyces cerevisiae ribosomal stalk: binding of P1 proteins is required for the interaction of P2 proteins.

The yeast ribosomal stalk is formed by a protein pentamer made of the 38 kDa P0 and four 12 kDa acidic P1/P2. The interaction of recombinant acidic proteins P1 alpha and P2 beta with ribosomes from Saccharomyces cerevisiae D4567, lacking all the 12 kDa stalk components, has been used to study the in vitro assembly of this important ribosomal structure. Stimulation of the ribosome activity was obtained by incubating simultaneously the particles with both proteins, which were nonphosphorylated initially and remained unmodified afterward. The N-terminus state, free or blocked, did not affect either the binding or reactivating activity of both proteins. Independent incubation with each protein did not affect the activity of the particles, however, protein P2 beta alone was unable to bind the ribosome whereas P1 alpha could. The binding of P1 alpha alone is a saturable process in acidic-protein-deficient ribosomes and does not take place in complete wild-type particles. Binding of P1 proteins in the absence of P2 proteins takes also place in vivo, when protein P1 beta is overexpressed in S. cerevisiae. In contrast, protein P2 beta is not detected in the ribosome in the P1-deficient D67 strain despite being accumulated in the cytoplasm. The results confirm that neither phosphorylation nor N-terminal blocking of the 12 kDa acidic proteins is required for the assembly and function of the yeast stalk. More importantly, and regardless of the involvement of other elements, they indicate that stalk assembling is a coordinated process, in which P1 proteins would provide a ribosomal anchorage to P2 proteins, and P2 components would confer functionality to the complex.

[Colostomy closure: is it an intervention without risk?]. / Cierre de colostomía: es una intervención sin riesgo?

OBJECTIVE: To examine whether colostomy closure is an operation with a high risk of complications. DESIGN: Retrospective study of colostomy closures in a 14-year period. PARTICIPANTS: 60 patients, averaging 54 years, males in 63%. The main indication for colostomy was colorectal neoplasm (47%), followed by trauma (23%). RESULTS: There were 15 Hartman's procedure reconstructions, 4 reconstructions of colostomy and mucous fistula, and 41 "simple" colostomy closures. The closure was extraperitoneal in 40%, suturing only the anterior colonic wall in 42%. We had 27 postoperative complications in 33% of the patients, without mortality. The average hospital stay was 8 days longer in the group with complications. The complication rate was 29% in the "simple" closure versus 42% in the reconstruction group (this difference was not statistically significant). The statistic analysis (chi-square and Mann-Whitney tests) showed no influence on morbidity of factors such as age, sex, previous disease, age of colostomy, and type and closure technique of colostomy. CONCLUSIONS: Colostomy closure has a high rate of postoperative complications (33%). These are minor in almost all cases, without mortality.