Predicting mortality in severe Covid-19 Pneumonia: the role of right ventricular dysfunction.

PURPOSE: There is evidence that COVID-19 can have a clinically significant effect on the right ventricle (RV). Our objective was to enhance the efficiency of assessing RV dilation for diagnosing ACP by utilizing both linear measurements and qualitative assessment and its usefulness as an independent predictor of mortality. METHODS: This is an observational, retrospective and single-center study of the Intensive Care Unit of the Sanatorio de Los Arcos in Buenos Aires, Argentina from March 2020 to January 2022. All patients admitted with acute respiratory distress syndrome due to COVID-19 pneumonia (C-ARDS) on mechanical ventilation who were assessed by transthoracic echocardiography (TTE) were included. RESULTS: A total of 114 patients with C-ARDS requiring invasive mechanical ventilation were evaluated by echocardiography. 12.3% had RV dilation defined as a RV basal diameter greater than 41 mm, and 87.7% did not. Acute cor pulmonale (ACP) defined as RV dilation associated with paradoxical septal motion was found in 6.1% of patients. 7% had right ventricular systolic dysfunction according to qualitative evaluation. The different RV echocardiographic variables were studied with a logistic regression model as independent predictors of mortality. In the multivariate analysis, both the RV basal diameter and the presence of ACP showed to be independent predictors of in-hospital mortality with OR of 3.16 (95% CI 1.36-7.32) and 3.64 (95% CI 1.05-12.65) respectively. CONCLUSION: An increase in the RV basal diameter and the presence of ACP measured by TTE are independent predictors of in-hospital mortality in patients with C-ARDS.

Evaluating the Utility of Portal Vein Pulsatility Index for Detecting Fluid Unresponsiveness in the Intensive Care Unit.

OBJECTIVE: The primary aim of the authors' study was to evaluate the capacity of the portal vein pulsatility index (PVP) to detect fluid unresponsiveness in patients admitted to intensive care. DESIGN: This was a retrospective, diagnostic accuracy study SETTING: At a tertiary medical-surgical intensive care unit in Buenos Aires, Argentina. PARTICIPANTS: Patients were included during usual care in the intensive care unit, who were evaluated by ultrasonography for the flow of the portal vein, calculating their PVP prior to fluid expansion. INTERVENTIONS: Patients who exhibited an increase of <15% in left ventricle outflow tract velocity-time integral after receiving 500 mL of Ringer Lactate were considered non-responders to fluids. MEASUREMENTS AND MAIN RESULTS: The authors included a total of 63 patients between January 2022 and October 2022. The area under the receiver operating characteristic curve for PVP to predict fluid unresponsiveness was 0.708 (95% CI 0.580 to 0.816). A value of the PVP >32% predicted fluid unresponsiveness with a sensitivity of 30.8% (95% CI 17% to 47.6%) and specificity of 100% (95% CI 85.8 to 100). The positive predictive value was 100%, and the negative predictive value was 47.1% (95% CI 41.9% to 52.3%). CONCLUSIONS: Although PVP has limited value as the sole indicator for fluid management decisions, it can be used as a stopping rule or combined with other diagnostic tests to improve the accuracy of fluid responsiveness assessment.

The Buckling Spectra of Nanoparticle Surfactant Assemblies.

Fine control over the mechanical properties of thin sheets underpins transcytosis, cell shape, and morphogenesis. Applying these principles to artificial, liquid-based systems has led to reconfigurable materials for soft robotics, actuation, and chemical synthesis. However, progress is limited by a lack of synthetic two-dimensional membranes that exhibit tunable mechanical properties over a comparable range to that seen in nature. Here, we show that the bending modulus, B, of thin assemblies of nanoparticle surfactants (NPSs) at the oil-water interface can be varied continuously from sub-kBT to 106kBT, by varying the ligands and particles that comprise the NPS. We find extensive departure from continuum behavior, including enormous mechanical anisotropy and a power law relation between B and the buckling spectrum width. Our findings provide a platform for shape-changing liquid devices and motivate new theories for the description of thin-film wrinkling.

Relationship of at Admission Lactate, Unmeasured Anions, and Chloride to the Outcome of Critically Ill Patients.

OBJECTIVES: To investigate the association between the concentration of the causative anions responsible for the main types of metabolic acidosis and the outcome. DESIGN: Prospective observational study. SETTING: Teaching ICU. PATIENTS: All patients admitted from January 2006 to December 2014. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Four thousand nine hundred one patients were admitted throughout the study period; 1,609 met criteria for metabolic acidosis and 145 had normal acid-base values. The association between at admission lactate, unmeasured anions, and chloride concentration with outcome was assessed by multivariate analysis in the whole cohort and in patients with metabolic acidosis. We also compared the mortality of patients with lactic, unmeasured anions, and hyperchloremic metabolic acidosis with that of patients without acid-base disorders. In the whole population, increased lactate and unmeasured anions were independently associated with increased mortality, even after adjusting for potential confounders (odds ratio [95% CI], 1.14 (1.08-1.20); p < 0.0001 and 1.04 (1.02-1.06); p < 0.0001, respectively). In patients with metabolic acidosis, the results were similar. Patients with lactic and unmeasured anions acidosis, but not those with hyperchloremic acidosis, had an increased mortality compared to patients without alterations (17.7%, 12.7%, 4.9%, and 5.8%, respectively; p < 0.05). CONCLUSIONS: In this large cohort of critically ill patients, increased concentrations of lactate and unmeasured anions, but not chloride, were associated with increased mortality. In addition, increased unmeasured anions were the leading cause of metabolic acidosis.

Memory persistence: from fundamental mechanisms to translational opportunities.

Memory persistence is a double edge sword. Persistence of adaptive memories is essential for survival and even determines who we are. Neurodegenerative conditions with significant memory loss such as Alzheimer's disease, testify how defects of memory persistence have severe and irreversible effects on personality, among other symptoms. Yet, maintenance of overly strong maladaptive memories underlies highly debilitating psychiatric conditions including post-traumatic stress disorder, specific phobia, substance dependence and binge eating disorder. Here we review the neurobiological mechanisms supporting memory formation, persistence, inhibition and forgetting. We then shift the focus to how such mechanisms have been exploited to alter the persistence of laboratory-generated memories in human healthy volunteers as a proof of concept. Finally, we review the effect of behavioural and pharmacological interventions in anxiety and addiction disorder patients, highlighting key findings, gaps, and future directions for basic and translational research.

Total endovascular repair of a common femoral artery aneurysm with a bifurcated endograft through a single ipsilateral approach.

Aneurysms of the common femoral and profunda femoris arteries are rare. Open surgical repair is the treatment of choice, even though hybrid and total endovascular repair with stent graft placement are reported in the literature. We describe a case of a successful total endovascular repair of a common femoral aneurysm extending to the profunda femoris with a bifurcated abdominal endograft placed in the common femoral artery with distal landing in profunda femoris and superficial femoral artery to preserve flow in both arteries. Endovascular repair of common femoral artery aneurysms with bifurcated endografts is a feasible alternative in complex anatomies.

Quantification of Engagement of Microtubules by Small Molecules in Living Cells by Flow Cytometry.

Drugs such as paclitaxel (Taxol) that bind microtubules are widely used for the treatment of cancer. Measurements of the affinity and selectivity of these compounds for their targets are largely based on studies of purified proteins, and only a few quantitative methods for the analysis of interactions of small molecules with microtubules in living cells have been reported. We describe here a novel method for rapidly quantifying the affinities of compounds that bind polymerized tubulin in living HeLa cells. This method uses the fluorescent molecular probe Pacific Blue-GABA-Taxol in conjunction with verapamil to block cellular efflux. Under physiologically relevant conditions of 37 °C, this combination allowed quantification of equilibrium saturation binding of this probe to cellular microtubules (K d = 1.7 µM) using flow cytometry. Competitive binding of the microtubule stabilizers paclitaxel (cellular K i = 22 nM), docetaxel (cellular K i = 16 nM), cabazitaxel (cellular K i = 6 nM), and ixabepilone (cellular K i = 10 nM) revealed intracellular affinities for microtubules that closely matched previously reported biochemical affinities. By including a cooperativity factor (α) for curve fitting of allosteric modulators, this probe also allowed quantification of binding (K b) of the microtubule destabilizers colchicine (K b = 80 nM, α = 0.08), vinblastine (K b = 7 nM, α = 0.18), and maytansine (K b = 3 nM, α = 0.21). Screening of this assay against 1008 NCI diversity compounds identified NSC 93427 as a novel microtubule destabilizer (K b = 485 nM, α = 0.02), illustrating the potential of this approach for drug discovery.

Dorsal striatum coding for the timely execution of action sequences.

The automatic initiation of actions can be highly functional. But occasionally these actions cannot be withheld and are released at inappropriate times, impulsively. Striatal activity has been shown to participate in the timing of action sequence initiation and it has been linked to impulsivity. Using a self-initiated task, we trained adult male rats to withhold a rewarded action sequence until a waiting time interval has elapsed. By analyzing neuronal activity we show that the striatal response preceding the initiation of the learned sequence is strongly modulated by the time subjects wait before eliciting the sequence. Interestingly, the modulation is steeper in adolescent rats, which show a strong prevalence of impulsive responses compared to adults. We hypothesize this anticipatory striatal activity reflects the animals' subjective reward expectation, based on the elapsed waiting time, while the steeper waiting modulation in adolescence reflects age-related differences in temporal discounting, internal urgency states, or explore-exploit balance.

Neutron-gamma dosimetry for BNCT using field oxide transistors with gadolinium oxide as neutron converter layer.

PURPOSE: A new type of electronic dosimeter is presented, capable of discerning between the doses of gamma photons and neutrons in a mixed beam as found in boron neutron capture therapy (BNCT). We introduce a real-time dosimeter based on a thick gate field oxide field effect transistor (FOXFET) covered with a neutron converter layer containing gadolinium. METHODS: To sensitize the FOXFET dosimeter to neutron fluxes, a converter layer containing gadolinium oxide particles embedded in photoresines was deposited over the sensor surface. Mixed neutron-gamma field configurations with different neutron energy spectra were used to assess the FOXFET response, considering different thicknesses of the neutron converter layer. RESULTS: The total gamma sensitivity of the devices resulted to be 43 mV/Gy. The responses of sensors with different converter layer thicknesses irradiated with different neutron spectra are simulated using GEANT4 code. The response to photons is not significantly modified with thin conversion layers when used in water medium. CONCLUSIONS: A real-time dosimeter comprising a pair of FOXFET sensors-only one of them with a gadolinium neutron converter layer-allows the simultaneous measurement of gamma dose and neutron flux during BNCT irradiations.

Multielectrode Recordings From Identified Neurons Involved in Visually Elicited Escape Behavior.

A major challenge in current neuroscience is to understand the concerted functioning of distinct neurons involved in a particular behavior. This goal first requires achieving an adequate characterization of the behavior as well as an identification of the key neuronal elements associated with that action. Such conditions have been considerably attained for the escape response to visual stimuli in the crab Neohelice. During the last two decades a combination of in vivo intracellular recordings and staining with behavioral experiments and modeling, led us to postulate that a microcircuit formed by four classes of identified lobula giant (LG) neurons operates as a decision-making node for several important visually-guided components of the crab's escape behavior. However, these studies were done by recording LG neurons individually. To investigate the combined operations performed by the group of LG neurons, we began to use multielectrode recordings. Here we describe the methodology and show results of simultaneously recorded activity from different lobula elements. The different LG classes can be distinguished by their differential responses to particular visual stimuli. By comparing the response profiles of extracellular recorded units with intracellular recorded responses to the same stimuli, two of the four LG classes could be faithfully recognized. Additionally, we recorded units with stimulus preferences different from those exhibited by the LG neurons. Among these, we found units sensitive to optic flow with marked directional preference. Units classified within a single group according to their response profiles exhibited similar spike waveforms and similar auto-correlograms, but which, on the other hand, differed from those of groups with different response profiles. Additionally, cross-correlograms revealed excitatory as well as inhibitory relationships between recognizable units. Thus, the extracellular multielectrode methodology allowed us to stably record from previously identified neurons as well as from undescribed elements of the brain of the crab. Moreover, simultaneous multiunit recording allowed beginning to disclose the connections between central elements of the visual circuits. This work provides an entry point into studying the neural networks underlying the control of visually guided behaviors in the crab brain.

Pressure Induced Stability Enhancement of Cubic Nanostructured CeO2 †.

Ceria (CeO2)-based materials are widely used in applications such as catalysis, fuel cells and oxygen sensors. Its cubic fluorite structure with a cell parameter similar to that of silicon makes it a candidate for implementation in electronic devices. This structure is stable in a wide temperature and pressure range, with a reported structural phase transition to an orthorhombic phase. In this work, we study the structure of CeO2 under hydrostatic pressures up to 110 GPa simultaneously for the nanometer- and micrometer-sized powders as well as for a single crystal, using He as the pressure-transmitting medium. The first-order transition is clearly present for the micrometer-sized and single-crystal samples, while, for the nanometer grain size powder, it is suppressed up to at least 110 GPa. We show that the stacking fault density increases by two orders of magnitude in the studied pressure range and could act as an internal constraint, avoiding the nucleation of the high-pressure phase.

Comparación de desempeño de algoritmos para el diagnóstico de sífilis / Performance comparison of algorithms for the diagnosis of syphilis / Comparação de desempenho de algoritmos para o diagnóstico da sífilis

Resumen La sífilis es una de las infecciones de transmisión sexual con mayor incidencia en la Argentina. Para su diagnóstico, el Ministerio de Salud de la Nación avala distintos algoritmos, entre ellos, el algoritmo tradicional y el reverso. En el algoritmo tradicional, la VDRL constituye la prueba de screening y los resultados positivos se confirman con la prueba treponémica de aglutinación de partículas (TPPA). El algoritmo reverso con un test rápido, avalado más recientemente, consiste en la realización de un test rápido treponémico como screening y posterior VDRL en las muestras que resulten positivas. Se realizó una comparación entre ambos algoritmos para evaluar si era factible y conveniente la implementación del algoritmo reverso con un test rápido en el laboratorio del H.I.G.A. Dr. Oscar Alende. El objetivo fue determinar la concordancia entre el algoritmo tradicional, utilizado actualmente en la institución (VDRL seguido por TPPA), y el nuevo algoritmo propuesto (test rápido treponémico Alere Determine Syphilis TP seguido por VDRL-USR). Para ello se realizó un estudio prospectivo de desempeño de métodos cualitativos. Se realizó VDRL-USR, TPPA y test rápido Alere Determine Syphilis TP en muestras de 580 pacientes, de los cuales 558 cumplieron con los criterios de inclusión. Se obtuvieron 51 muestras con resultados positivos y 507 con resultados negativos para el diagnóstico de sífilis por ambos algoritmos, con un porcentaje de concordancia global del 100%, lo cual indica que podría reemplazarse el algoritmo tradicional por el reverso en aquellas situaciones que lo requieran en la población estudiada.

Abstract Syphilis is one of the sexually transmitted infections with the highest incidence in Argentina. For its diagnosis, the Ministry of Health of the Nation endorses different algorithms, among them, the traditional algorithm and the reverse. In the traditional algorithm, VDRL constitutes the screening test and positive results are confirmed with particle agglutination assay TPPA. The reverse algorithm with rapid test, endorsed more recently, consists of performing a rapid treponemal test as screening and subsequent VDRL in the samples that are positive. A comparison was made between both algorithms to evaluate if the implementation of the reverse algorithm with rapid test in Dr. Oscar Alende Hospital would be feasible and convenient. The objective of this work was to determine the concordance between the traditional algorithm, currently used in the institution (VDRL followed by TPPA), and the new algorithm proposed (rapid treponemal test Alere Determine Syphilis TP followed by VDRL-USR). For that purpose, a prospective study of the performance of qualitative methods was carried out. VDRL-USR, TPPA and Alere Determine Syphilis TP Rapid Test were performed on samples from 580 patients, of which 558 met the inclusion criteria. A total of 51 samples with positive results and 507 with negative results for the diagnosis of syphilis were obtained by both algorithms, with an overall concordance percentage of 100%, which indicates that the traditional algorithm could be replaced by the reverse in those situations that require it in the studied population.

Resumo A sífilis é uma das infecções sexualmente transmissíveis com maior incidência na Argentina. Para o seu diagnóstico, o Ministério da Saúde da Nação endossa diversos algoritmos, incluindo o algoritmo tradicional e o reverso. No algoritmo tradicional, o VDRL constitui o teste de triagem e os resultados positivos são confirmados com o teste treponêmico de aglutinação de partículas (TPPA). O algoritmo reverso com teste rápido, endossado mais recentemente, consiste na realização de um teste rápido treponêmico como triagem e posterior VDRL nas amostras positivas. Foi feita uma comparação entre os dois algoritmos para avaliar se a implementação do algoritmo reverso com um teste rápido no laboratório H.I.G.A. Dr. Óscar Alende era viável e conveniente. O objetivo foi determinar a concordância entre o algoritmo tradicional, atualmente utilizado na instituição (VDRL seguido de TPPA), e o novo algoritmo proposto (teste rápido treponêmico Alere Determine Syphilis TP seguido de VDRL-USR). Para tanto, foi realizado um estudo prospectivo de desempenho de métodos qualitativos. O VDRL- -USR, o TPPA e o teste rápido Alere Determine Syphilis TP foram realizados em amostras de 580 pacientes, dos quais 558 preencheram os critérios de inclusão. Foram obtidas 51 amostras com resultados positivos e 507 com resultados negativos para o diagnóstico de sífilis por ambos os algoritmos, com um percentual de concordância global de 100%, o que indica que o algoritmo tradicional poderia ser substituído pelo reverso nas situações que o exigissem na população estudada.

A transient increase in the activity of Src-family kinases induced by cell detachment delays anoikis of intestinal epithelial cells.

Detachment of epithelial cells from the basement membrane (BM) induces apoptosis, a phenomenon now widely known as anoikis. Studies in mammary and intestinal epithelial cells have shown that the loss of attachment to the BM rapidly triggers reversible proapoptotic events from which the cells can recover if they reattach within a certain period. Thus, cells seem to be transiently protected from the initial detachment-induced proapoptotic events. The molecular mechanisms underlying such transient protection against anoikis are unknown. In this paper, we present evidence indicating that detachment of intestinal epithelial cells triggers a transient, yet significant increase in the activity of the tyrosine kinases c-Src and c-Fyn, and that this activation of Src-family kinases (SFK) contributes to the transient protection against anoikis in these cells. The protective signals from SFK are mediated by the PI3K pathway, and caveolin-1. In addition, we show that the MEK1-ERK1/2 pathway acts in a synergistic manner with SFK to protect intestinal epithelial cells from anoikis.

Evaluación de los límites analíticos de desempeño del laboratorio del HIGA O. Alende de Mar del Plata / Evaluation of analytical limits of performance in the laboratory of HIGA O. Alende of Mar del Plata / Avaliação dos limites analíticos de desempeno do laboratório do HIGA O. Alende de Mar del Plata

Los límites analíticos de desempeño (LAD) forman parte del diseño del programa de control de calidad analítico. Los objetivos de este trabajo fueron determinar imprecisión (CV), error sistemático (ES) y error total (ET) de 14 analitos de Química Clínica en los sectores de planta y de guardia del laboratorio del HIGA O. Alende de Mar del Plata, evaluar su desempeño analítico según variabilidad biológica y comparar los datos obtenidos. Se realizó un estudio retrospectivo con el registro de controles de calidad y se utilizaron los LAD derivados de VB para obtener las especificaciones de calidad para CV, ES y ET. Respecto del CV, cumple con los criterios el 79% en el sector planta y el 64% en el de guardia. Y en cuanto al ET, cumple el 90% y el 75%, respectivamente. En conclusión, aunque la mayoría de los analitos evaluados cumplen al menos con los criterios mínimos establecidos, los resultados ponen de manifiesto la necesidad de mejorar el desempeño analítico. Detectar los tipos de errores presentes en el proceso de laboratorio es el primer paso para instaurar controles de procedimiento y análisis, soluciones que permitirán mejorar la calidad analítica, uno de los pilares que optimizan la seguridad del paciente.

The analytical limits of performance (ALP) are part of the programme design of analytical quality control. The goals of this study were to determine imprecision (VC), systematic error (SE) and total error (TE) of 14 clinical chemistry analytes in the routine and emergency laboratory of HIGA O. Alende of Mar del Plata, to evaluate their analytical performance in accordance with biological variability, and compare the data obtained. A retrospective study was performed using the record of quality controls. The ALP were obtained from BV to get the quality specifications for VC, SE and TE. Regarding VC, 78% of the analytes meet the criteria in the routine laboratory and 64% in the emergency. Regarding TE, in the routine laboratory, 90% meet the TE criteria, and 75% in the emergency. It can be concluded that, although most of the evaluated analytes meet at least the minimum established criteria, the results highlight the need to improve the analytical performance. Detecting the types of errors in the laboratory process is the first step to establish procedural and analysis controls. These are solutions that will improve the analytical quality, one of the pillars to optimize patient safety.

Os limites analíticos de desmpeño (LAD) são parte do desenho do programa de controle de qualidade analítico. Os objetivos deste estudo foram determinar a imprecisão (CV), o erro sistemático (ES) e o erro total (ET) de 14 analitos de Química Clínica nas áreas de planta e de plantão do laboratório HIGA O. Alende de Mar del Plata, avaliar seu desempenho analítico de acordo com a variabilidade biológica e comparar os dados obtidos. Um estudo retrospectivo foi realizado com o registro de controles de qualidade utilizando os LAD derivados de VB para obter as especificações de qualidade para CV, ES e ET. Quanto ao CV, 79% cumpre com os critérios no setor da planta e 64% no setor de plantão. E, quanto ao ET, cumpre 90% e 75% respectivamente. Em conclusão, embora a maioria dos analitos testados cumpra pelo menos com os critérios mínimos estabelecidos, os resultados destacam a necessidade de melhorar o desempenho analítico. Detectar os tipos de erros encontrados no processo de laboratório é o primeiro passo para estabelecer controles de procedimento e análise, soluções que permitirão melhorar a qualidade analítica, um dos pilares que otimizam a segurança do paciente.

Estudio exploratorio de la interacción colaborativa infantil en la realización de dibujos libres / Peer Collaboration among Children in a Free Drawing Task: An Exploratory Study / Estudo exploratório da interação colaborativa infantil na realização de desenhos livres

Objetivo. Realizar un estudio exploratorio y microanalítico de la interacción colaborativa infantil entre pares, en la realización de dibujos libres (tarea de final abierto). Analizar las características diferenciales de dicho proceso en función del grupo etario y del contexto socioeconómico. Método. Estudio evolutivo transversal en el que participaron 82 niños, agrupados en 41 díadas, de 4, 8 y 12 años, pertenecientes a contextos socioeconómicos favorecido y desfavorecido. Cada díada realizó un dibujo libre colaborativo. El instrumento utilizado fue la observación. La interacción fue analizada desde dos perspectivas: modalidad social de ejecución de la tarea y verbalización específica. En cada caso se aplicó un sistema de categorías diferente. Los datos resultantes se procesaron mediante técnicas de análisis factorial y de clasificación. Resultados. Se evidenciaron tres modalidades interactivas generales: disociativa (asociada mayormente a díadas de 4 años), mixta (colaborativa-asimétrica) y cooperativa (las dos últimas mayormente asociadas a díadas de 8 y 12 años). También se detectaron asociaciones específicas entre modalidad mixta-contexto desfavorecido y modalidad cooperativa-contexto favorecido. Conclusión. El trabajo aporta nueva evidencia empírica respecto a dos tendencias que actualmente confluyen en las investigaciones sobre colaboración entre pares: (a) el énfasis puesto en el microanálisis de la interacción y (b) el creciente interés en tareas colaborativas expresivas o libres, diferentes a las tareas tradicionalmente estudiadas (resolución de problemas y aprendizaje de nociones científicas y matemáticas). También, el trabajo aborda la interacción colaborativa a partir de la consideración integrada de acción y palabra, generalmente analizadas por separado.

Objective. This paper presents an exploratory and micro-analytical study of peer collaboration among children in a free drawing task. The characteristics of this process were also analyzed according to age group and socioeconomic context. Method. Cross-sectional research in which 82 children were grouped into 41 dyads. They were 4-, 8- and 12-years-old, belonging to advantaged and disadvantaged socioeconomic contexts. Each dyad performed a collaborative free drawing task. The main instrument was observation. The interaction was analyzed from two approaches: social modality of execution, and specific verbalization. Each approach was coded by a different system of categories. The data was processed by factorial and cluster analysis. Results. Data showed three global interactive modalities: dissociative (mainly associated with 4-years-old dyads), mixed (collaborative-asymmetrical) and cooperative (the last two mainly associated with 8- and 12-years-old dyads). Also detected were specific associations between mixed modality - disadvantaged context and cooperative modality - advantaged contexts. Conclusion. The study offers new evidence on two main issues in recent studies on peer collaboration: a) the focus on the micro-analysis of interaction; b) the growing interest on more open-ended tasks compared to traditionally addressed tasks (problem solving and tasks in science or mathematics). Also, the current paper allows analyzing action and language jointly in collaborative interaction, considering that they were studied separately in most of investigations.

Escopo. Fazer um estudo exploratório e microanalítico da interação colaborativa infantil entre pares, na realização de desenhos livres (tarefa de final aberto). Analisar as características diferenciais de dito processo em função do grupo etário e do contexto socioeconómico. Metodologia. Estudo evolutivo transversal donde participaram 82 crianças agrupadas em 41 díades, de 4, 8 e 12 anos de idade e pertencentes a contextos socioeconómicos favorecido e desfavorecido. Cada uma das díades fez um desenho livre colaborativo. O instrumento utilizado foi a observação. A interação foi analisada desde duas perspectivas: modalidade social de execução da tarefa e verbalização específica. Em cada caso foi aplicado um sistema de categoria diferente. Os dados resultantes foram processados mediante técnicas de análise fatorial e de classificação. Resultados. Foram evidenciadas três modalidades interativas gerais: dissociativa (associada maiormente a díades de 4 anos de idade), mista (colaborativa-assimétrica) e cooperativa (as duas últimas maiormente associadas a díades de 8 e 12 anos de idade). Também foram detectados associações específicas entre modalidade mista -contexto desfavorecido e modalidade cooperativa- contexto favorecido. Conclusão. O trabalho aporta nova evidencia empírica respeito a duas tendências que atualmente confluem nas pesquisas sobre colaboração entre pares: a) o ênfase posto no microanálise da interação; b)o crescente interesse em tarefas colaborativas expressivas ou livres, diferente das tarefas tradicionalmente estudadas (resolução de problemas e aprendizagem de noções científicas e matemáticas). Também, o trabalho aborda a interação colaborativa a partir da consideração integrada de ação e palavra, geralmente analisadas por separado.

Definiciones teóricas y áreas de investigación propuestas desde el constructivismo, en publicaciones latinoamericanas de psicología y educación presentes en la base de datos redalyc / Theoretical definitions and research areas proposed from constructivism, in latin american publications of psychology and education in database redalyc

El objetivo del presente trabajo fue brindar una síntesis actualizada de los lineamientos teóricos y áreas de investigación abordada desde el constructivismo, en revistas latinoamericanas de psicología y educación publicadas durante los últimos diez años aproximadamente. Con tal fin, se exploró la base de datos REDALYC, por ser considerada uno de los principales repositorios latinoamericanos de acceso abierto, con disponibilidad de artículos completos vinculados al área de psicología y educación. En primer lugar, se analizaron los supuestos epistemológicos del constructivismo. En segundo lugar, ya en relación directa con la psicología y la educación, se repasaron los aspectos centrales y las diferenciaciones teóricas internas de dicha perspectiva. Finalmente, se identificaron algunas tendencias temáticas abordadas desde constructivismo en psicología y educación, presentes en la base de datos explorada. Las mismas se agruparon en torno a tres áreas: estrategias de enseñanza aprendizaje, didáctica de las ciencias, incorporación de las TICs a los procesos de enseñanza-aprendizaje...

This paper aimed to provide an updated summary of theoretical tendences and research areas proposed from constructivism, in Latin American journals of psychology and education published during last ten years. For that, we explored the database REDALYC, which is considered as one of main Latin American open-access repository, with full text articles linked to psychology and education. First, we analyzed the epistemological assumptions of constructivism. Then, directly related to psychology and education, we reviewed central aspects and internal theoretical distinctions of this perspective. Finally, we identified some research topics studied from constructivism in psychology and education, in explored database. These were grouped into three areas: teaching and learning strategies, science teaching, and incorporation of TICs into teaching and learning process...

Diagnóstico y planeamiento protético para la adecuada posición tridimensional del implante dental / Prosthetic diagnosis and planning for an accurate three-dimensional position of the implant

El concepto clínico de una restauración implantosoportada exitosa ha evolucionado más allá del mero reestablecimiento de la función. El reemplazo de una pieza ausente no resulta suficiente si no se establece la estética adecuada. Los resultados estéticos están directamente ligados a la correcta colocación quirúrgica del implante. El artículo describe conceptos protéticos relacionados con el diagnóstico, plan de tratamiento y la ubicación tridimensional del implante dental

Sobredentadura mandibular implantosoportada: una alternativa para pacientes con dificultades en la higiene oral / Implant-supported mandibular overdenture: an alternative for patients with problems in oral hygiene

Los implantes dentales han demostrado su éxito en el tratamiento de pacientes desdentados. Diversos diseños pueden utilizarse para rehabilitar con efectividad a estos pacientes: prótesis híbrida tipo Branemark, prótesis fija convencional implantosoportada y sobredentaduras implantorretenidas o implantosoportadas. En pacientes con deficiencias en la higiene bucal, una prótesis implantosoportada de tipo removible podría ser beneficiosa. El objetivo de este trabajo es presentar un caso clínico en el que se describen los procedimientos clínicos y de laboratorio para la fabricación de una sobredentadura mandibular implantosoportada