Synthesis, characterization and stability of crosslinked chitosan-maltodextrin pH-sensitive nanogels.

Polysaccharide-based nanogels offer a wide range of chemical compositions and are of great interest due to their biodegradability, biocompatibility, non-toxicity, and their ability to display pH, temperature, or enzymatic response. In this work, we synthesized monodisperse and tunable pH-sensitive nanogels by crosslinking, through reductive amination, chitosan and partially oxidized maltodextrins, by keeping the concentration of chitosan around the overlap concentration, i.e. in the dilute and semi-dilute regime. The chitosan/maltodextrin nanogels presented sizes ranging from 63 ±â€¯9 to 279 ±â€¯16 nm, showed quasi-spherical and cauliflower-like morphology, reached a ζ-potential of +36 ±â€¯2 mV and maintained a colloidal stability for up to 7 weeks. It was found that the size and surface charge of nanogels depended both on the oxidation degree of maltodextrins and chitosan concentration, as well as on its degree of acetylation and protonation, the latter tuned by pH. The pH-responsiveness of the nanogels was evidenced by an increased size, owed to swelling, and ζ-potential when pH was lowered. Finally, maltodextrin-chitosan biocompatible nanogels were assessed by cell viability assay performed using the HEK293T cell line.

Porous Structural Properties of K or Na-Co Hexacyanoferrates as Efficient Materials for CO2 Capture.

The stoichiometry of the components of hexacyanoferrate materials affecting their final porosity properties and applications in CO2 capture is an issue that is rarely studied. In this work, the effect that stoichiometry of all element components and oxidation states of transition metals has on the structures of mesoporous K or Na-cobalt hexacyanoferrates (CoHCFs) and CO2 removal is reported. A series of CoHCFs model systems are synthesized using the co-precipitation method with varying amounts of Co ions. CoHCFs are characterized by N2 adsorption, TGA, FTIR-ATR, XRD, and XPS. N2 adsorption results reveal a more developed external surface area (72.69-172.18 m2/g) generated in samples containing mixtures of K+/Fe2+/Fe3+ ions (system III) compared to samples with Na+/Fe2+ ions (systems I, II). TGA results show that the porous structure of CoHCFs is affected by Fe and Co ions oxidation states, the number of water molecules, and alkali ions. The formation of two crystalline cells (FCC and triclinic) is confirmed by XRD results. Fe and Co oxidation states are authenticated by XPS and allow for the confirmation of charges involved in the stabilization of CoCHFs. CO2 removal capacities (3.04 mmol/g) are comparable with other materials reported. CO2 adsorption kinetics is fast (3-6 s), making CoHCFs attractive for continuous operations. Qst (24.3 kJ/mol) reveals a physical adsorption process. Regeneration effectiveness for adsorption/desorption cycles indicates ~1.6% loss and selectivity (~47) for gas mixtures (CO2:N2 = 15:85). The results of this study demonstrate that the CoHCFs have practical implications in the potential use of CO2 capture and flue gas separations.

Oil-in-eutectic mixture HIPEs co-stabilized with surfactant and nanohydroxyapatite: ring-opening polymerization for nanocomposite scaffold synthesis.

Mixtures of a nonionic surfactant and non-functionalized nanohydroxyapatite (NHA) enhanced the stability of oil-in-eutectic mixture high internal phase emulsions (HIPEs). Upon ring opening polymerization of the eutectic mixture composed of l-lactide and ε-caprolactone, biodegradable polyHIPEs with specific cavity sizes and selective interfacial functionalization with NHA are produced.

Structure of reverse microemulsion-templated metal hexacyanoferrate nanoparticles.

The droplet phase of a reverse microemulsion formed by the surfactant cetyltrimethylammonium ferrocyanide was used as a matrix to synthesize nanoparticles of nickel hexacyanoferrate by adding just a solution of NiCl2 to the microemulsion media. Dynamic light scattering and small-angle neutron scattering measurements show that the reverse microemulsion droplets employed have a globular structure, with sizes that depend on water content. Transmission electron microscopy and electron diffraction are used to obtain information about the structure of the synthesized nanoparticles. The results show that the size and shape of the coordination compound nanoparticles correspond with the size and shape of the droplets, suggesting that the presented system constitutes an alternative method of the synthesis of metal hexacyanoferrate nanoparticles.

Precipitating factors leading to decompensation of chronic heart failure in the elderly patient in South-American community hospital.

BACKGROUND: Exacerbations of heart failure appear frequently associated with precipitating factors not directly related to the evolution of cardiac disease. There still a paucity of data on the proportional distribution of precipitating factors specifically in elderly patients. The aim of this study was to examine prospectively the precipitating factors leading to hospitalization in elderly patients with heart failure in our community hospital. METHODS: We evaluate elderly patients who need admissions for decompensate heart failure. All patients were reviewed daily by the study investigators at the first 24 h and closely followed-up. Decompensation was defined as the worsening in clinical NYHA class associated with the need for an increase in medical treatment (at minimum intravenously diuretics). RESULTS: We included 102 patients (mean age 79 ± 12 years). Precipitating factors were identified in 88.5%. The decompensation was sudden in 35% of the cases. Noncompliance with diet was identified in 52% of the patients, lack of adherence to the prescribed medications amounted to 30%. Others precipitating factors were infections (29%), arrhythmias (25%), acute coronary ischemia (22%), and uncontrolled hypertension (15%), miscellaneous causes were detected in 18% of the cases (progression of renal disease 60%, anemia 30% and iatrogenic factors 10%). Concomitant cause was not recognizable in 11.5%. CONCLUSIONS: Large proportion heart failure hospitalizations are associated with preventable precipitating factors. Knowledge of potential precipitating factors may help to optimize treatment and provide guidance for patients with heart failure. The presence of potential precipitating factors should be routinely evaluated in patients presenting chronic heart failure.

Los efectos de la activación de estereotipos sobre la evaluación de candidatos en un contexto experimental de selección de personal / Effects of stereotypes activation on the job candidates assessment in an experimental context of personnel selection

La mayoría de las personas quieren ser (y parecer) racionales y objetivas a la hora de tomar decisiones, sobre todo en contextos profesionales. Sin embargo, multitud de variables aparentemente irrelevantes pueden sesgar los juicios y los comportamientos de las personas. La presente investigación demuestra que la evaluación de un potencial candidato a un puesto de trabajo en un contexto experimental de selección de personal puede verse influida por la activación previa de estereotipos. En concreto, se pidió a un grupo de participantes que completaran palabras relacionadas con el estereotipo de ejecutivo o de skinhead (cabeza rapada) y, a continuación, se presentó una información ambigua sobre un supuesto candidato a un puesto de trabajo. Tal y como se esperaba, las actitudes y valoraciones hacia el candidato fueron más favorables en el primer caso. En el presente trabajo se discuten los posibles procesos psicológicos subyacentes a este efecto, así como las estrategias de control mental que pueden ayudar a reducir este tipo de sesgos.

Most people want to be (and be seem) rational and objective when making decisions, particularly in professional domains. However, a large number of irrelevant factors can bias judgments and behaviors. The present research reveals that attitudes toward potential job candidates can be influenced by stereotype activation in an experimental context. Specifically, participants were asked to complete words related to the stereotype of businessman or to the stereotype of skinhead prior to receiving ambiguous information about a fictitious job candidate. As predicted, attitudes and perceptions toward the candidate were more favorable in the former than in the later priming condition. Possible underlying psychological mechanisms and strategies for bias reductionare discussed.

The effects of message recipients' power before and after persuasion: a self-validation analysis.

In the present research, the authors examined the effect of a message recipient's power on attitude change and introduced a new mechanism by which power can affect social judgment. In line with prior research that suggested a link between power and approach tendencies, the authors hypothesized that having power increases confidence relative to being powerless. After demonstrating this link in Experiment 1, in 4 additional studies, they examined the role of power in persuasion as a function of when power is infused into the persuasion process. On the basis of the idea that power validates whatever mental content is accessible, they hypothesized that power would have different effects on persuasion depending on when power was induced. Specifically, the authors predicted that making people feel powerful prior to a message would validate their existing views and thus reduce the perceived need to attend to subsequent information. However, it was hypothesized that inducing power after a message has been processed would validate one's recently generated thoughts and thus influence the extent to which people rely upon their thoughts in determining their attitudes.

Seasonal variation and trends in heart failure morbidity and mortality in a South American community hospital.

Circannual variation in cardiovascular events is well-known. Seasonal variation (SV) in heart failure (HF) has been described in the Northern Hemisphere, but there is scarcity of data in South America. The goals of the present study were to (1) describe the SV of admissions and deaths for HF, and (2) describe trends in HF morbidity and mortality in a community hospital in Argentina from 1992 to 1999. The study sample included 6369 admissions. During this period, the number of HF admissions rose by 188% and the rate HF admissions/all admissions increased from 3.28% to 7.84%. In-hospital mortality decreased from 21% to 13%. HF admissions followed a seasonal pattern with a winter-spring predominance. Male and very old patients were the subgroups with the highest SV. The authors identified clear SV in HF deaths and admissions, which raises a different hypothesis about the rationale of HF admissions and provides information for the organization of care and resource allocation.

[The impact of training on interpersonal influence]. / El efecto de la formación sobre la influencia interpersonal.

Contemporary research on interpersonal influence has shown that individuals scoring high in Need for Cognition (NC) are able to generate a large number of arguments in order to convince other people. However, research has also shown that such an effort does not necessarily lead them to be more persuasive or more efficient in their group performance. The present research analysed this state of affairs, replicating and extending previous research by showing that appropriate training in socio-emotional group dimensions can increase group performance for individuals high in NC. Potential underlying mechanisms for such an effect are discussed.

El efecto de la formación sobre la influencia interpersonal / The impact of training on interpersonal influence

La investigación contemporánea sobre influencia interpersonal ha demostrado que las personas con alta Necesidad de Cognición (NC) son capaces de generar numerosos argumentos para convencer a otras personas. No obstante, también se ha demostrado que estos esfuerzos por influir sobre las personas no llevan necesariamente a un desempeño más eficaz de los grupos. En el presente trabajo de investigación se ha profundizado en estas cuestiones, confirmando los resultados de trabajos previos y apuntando a nuevas direcciones en la investigación, al demostrar que una adecuada formación sobre los aspectos socioemocionales de los grupos hace que el rendimiento aumente en los grupos en los que participan personas con alta NC. A la luz del presente estudio, se analizaron los posibles mecanismos a través de los cuales la formación pudo tener este efecto sobre el rendimiento

Contemporary research on interpersonal influence has shown that individuals scoring high in Need for Cognition (NC) are able to generate a large number of arguments in order to convince other people. However, research has also shown that such an effort does not necessarily lead them to be more persuasive or more efficient in their group performance. The present research analysed this state of affairs, replicating and extending previous research by showing that appropriate training in socio-emotional group dimensions can increase group performance for individuals high in NC. Potential underlying mechanisms for such an effect are discussed

El efecto de la necesidad de cognición sobre la influencia interpersonal / The impact of need for cognition on interpersonal influence

La Necesidad de Cognición (NC) se refiere a la motivación y preferencia que muestran las personas hacia la actividad de pensar (Cacioppo y Petty, 1982). Puesto que las personas con alta NC forman y cambian sus opiniones a través de la elaboración detallada de la información, sus actitudes suelen ser relativamente resistentes al cambio. La presente investigación examina el papel que la NC juega en los procesos de influencia interpersonal. Los resultados del estudio pusieron de manifiesto que, comparados con los participantes con baja NC, aquellos con alta NC se esforzaron más por convencer a sus compañeros, generando un mayor número de argumentos persuasivos. Sin embargo, a pesar de este esfuerzo, se encontró que los participantes con alta NC resultaron menos efectivos en resolver la tarea grupal a medida que el tamaño del grupo aumentó. En el presente trabajo se discuten distintas explicaciones potenciales para dar cuenta de este efecto

The Need for Cognition (NC) refers to the tendency to engage in and enjoy effortful thought (Cacioppo and Petty, 1982). Since individuals with high NC tend to base their attitudes on extensive thinking, their attitudes also tend to be relatively resistant to change. The present research examined the impact of NC on interpersonal influence processes. In one study, we predicted and found that, relative to participants with low NC, those with high NC were able to generate more high quality arguments to convince other members of the group. However, this study also showed that participants with high NC were increasingly less efficient in reaching group consensus as the size of the group increased. A number of potential mechanisms for this findings are discussed

Validación del pensamiento y persuasión / Thought-validation and persuasion

La persuasión depende de lo que las personas piensan (respuestas cognitivas) sobre la información que reciben. Hasta ahora, se han estudiado dos dimensiones de estas respuestas cognitivas: la dirección de los pensamientos (favorables o desfavorables) y la cantidad de los pensamientos (si se piensa mucho o poco). La investigación más reciente demuestra que es necesario considerar una tercera dimensión del pensamiento: la confianza en los propios pensamientos. En el presente trabajo se estudia una nueva variable que influye sobre dicha confianza: la autoafirmación. Después de procesar un mensaje persuasivo, a los participantes del experimento se les permitió autoafirmarse a través de la expresión de sus valores personales, lo que incidió significativamente sobre la confianza de los sujetos respecto a sus pensamientos sobre el mensaje. Como resultado, la autoafirmación aumentó la persuasión cuando los pensamientos sobre el mensaje fueron favorables, pero la disminuyó cuando los pensamientos sobre el mismo fueron desfavorables (AU)

Persuasion depends on how people respond (cognitive responses) to the information they receive. Two aspects of these cognitive responses have been emphasized so far on the study of persuasion: the direction of thinking (whether thinking is favorable or unfavorable) and the extent of thinking (whether thinking is extensive or minimal). Recent research has demonstrated that it is necessary to take into account a third dimension of thinking based on people’s confidence in their own thoughts. The present research explores a new variable that influences persuasion by affecting thought-confidence: self-affirmation. We predicted and found that when participants were affirmed (by expressing personal values) after message processing, self-affirmation affected attitude change by influencing the confidence with which cognitive responses to the message were held. As a consequence, self-affirmation magnified the impact of thoughts on attitudes enhancing persuasion when thoughts were favorable and undermined it when thoughts were unfavorable (AU)

Equilibrio cognitivo implícito / Implicit cognitive equilibrium

En el presente trabajo se reevaluaron las teorías clásicas de la consistencia cognitiva desde una nueva perspectiva teórica y metodológica basada en los modelos de cognición social implícita. Según este reciente enfoque, cambiar una actitud supone transformar la fuerza con la que el objeto de actitud se asocia a una valencia (bueno o malo). Puesto que el "Yo" ocupa un lugar central en las redes de representación semántica, cuando se cambia una actitud, la tendencia de las personas hacia el equilibrio cognitivo puede producir también cambios en la relación de dicho objeto de actitud con el "Yo". En el presente trabajo se comprobó empíricamente esta hipótesis evaluando el efecto sobre el "Yo" de la manipulación de las asociaciones automáticas entre distintos estímulos. En concreto, cuanto más favorables se hicieron las actitudes implícitas hacia un objeto, mayor asociación automática se encontró entre dicho objeto y el "Yo" (AU)

The classic theories of cognitive consistency were re-analyzed based on the new theoretical and methodological perspectives of implicit social cognition. According with this view, when an attitude changes, the strength with which the attitude object becomes associated with the valence (positive or negative) is modified. It is postulated that because of the central role played by the «Self» in the semantic representation net, when an attitude changes, people will tend to keep cognitive equilibrium by changing the relationship between the attitude object and the «Self». In the present research that hypothesis was empirically tested by assessing the impact of manipulating the automatic evaluation between different stimuli on the «Self». Specifically, the more favorable the induced implicit attitudes, the greater the association between the attitude object and the self (AU)

Cambio de aptitudes implícitas / Implicit attitude change

Las medidas explícitas de las actituides (e.g. auto-informes y cuestionarios) hacen referencia a juicios evaluativos relativamente controlados, deliberados y conscientes. Las medidas implícitas de las actitudes (e.g., priming y test de actitudes implícitas) constituyen evaluaciones más rápidas, insconcientes y difíciles de controlar. De estas últimas se derivan las denominadas actitudes implícitas de las personas, que se caracterizan por su fuerza, estabilidad y duración en el tiempo. La presente investigación demuestra que tales evaluaciones automáticas son objeto de persuasión. Se pidió a un grupo de sujetos que leyeran un mensaje persuasivo compuesto por argumentos fuertes o débiles y se midieron las actitudes hacia la propuesta, tanto de forma explicita como implícita. Los resultados demuestran que, si bien las actitudes explícitas de los participantes no se ven influidas por los mensajes, las actitudes implícitas reflejan el efecto la calidad de los argumentos, sobre todo para aquellos participantes con mayor motivación para elaborar la información (AU)

Recent attitude research has focused considerable attention on the distinction between implicit and explicit social judgments. Relative to explicit measures, implicit measures (e.g., sequential priming, Implicit Associative Test) are more likely to assess judgments that are fast, unintentional, uncontrollable, unconscious, or nonreactive. In contrast, explicit measures (e.g., questionnaire measures) often assess intentional judgments that involve greater awareness, control, deliberation, or social editing. The general assumption is that implicit attitudes (i.e., automatic evaluation) are strong, stable, and resistant to change. Our research suggested that implicit attitudes are not immutable and can be persuaded. Participants were asked to read a persuasive message, composed by strong or weak arguments. Both explicit and implicit attitudes toward the proposal were assessed. The explicit measures of the attitudes did not reveal any change, whereas the implicit measures showed a significant effect of the argument quality, specially for those participants high in need for cognition (AU)

Validación de la escala de necesidad de cognición y su aplicación al estudio del cambio de actitudes / Validation of the need for cognition scale and its application to attitude change

El propósito de la presente investigación consiste en la validación en el contexto español de la escala de Necesidad de Cognición (NC) (Cacioppo y Petty, 1982), la cual permite clasificar a las personas según el grado en el que se muestran motivados hacia la actividad de pensar. En el primer estudio se aplicó la escala a una muestra de 561 estudiantes, profesores y trabajadores universitarios. Mediante el análisis factorial confirmatorio, se identificaron dos subescalas, una positiva que refleja la tendencia a la elaboración cognitiva, y otra negativa que mide la tendencia a rechazar y evitar situaciones que requieran un alto grado de elaboración. En cuanto a la validez, los altos en NC generaron un mayor número de pensamientos en relación con sus preferencias que aquellos con baja NC. Además, cuando se compararon las respuestas de distintos colectivos, los profesores obtuvieron puntuaciones mayores de NC que los estudiantes y el personal de servicios. En el segundo estudio, 82 estudiantes fueron expuestos a un mensaje persuasivo y completaron la escala NC. se reaplicaron los resultados del primer estudio y se confirmaron las características psicométricas. En cuanto a la validez, de acuerdo con el modelo ELM (elaboration likelihood Model) (Petty y Cacioppo, 1986) se encontró que comparados con los bajos en NC, los altos en NC pensaron más sobre el contenido del mensaje, generaron más pensamientos al respecto y recordaron más argumentos, mostrándose más persuadidos por la versión fuerte del mensaje que por la débil (AU)

The goal of the present research was to validate the Spanish version of the Need for Cognition Scale (NC, Cacioppo & Petty, 1982). This Scale measures the extent in which people is chronically motivated to think. In the first study, 561 university students, professors and staff personnel completed the NC scale. Confirmatory factor analysis supports a two factor structure, with a positive factor related to the tendency to elaborate and the other negative, related with the tendency to avoid and reject situations of elaboration. In contrast with low NC participants, the number of thoughts generated by high NC participants was higher. It was also found that professors showed higher scores in NC than students and workers did. In a second study, 82 participants were asked to read a persuasive message, to list their cognitive responses and attitudes and then, answered to the NC scale. Findings from the first study were replicated. With regard to attitude change, results showed that compared with low NC participants, people with higher scores in the scale thought more about the content of the message, generated more cognitive responses, recalled more arguments, and were more persuaded by the strong than the weak version of the persuasive message (AU)

Conocimiento social de la mentira y credibilidad / Deception social knowledge and credibility

El presente trabajo persigue un mejor conocimiento de los procesos psicosociales que afectan la evaluación de la credibilidad en personas desconocidas. La hipótesis general que manejamos es que el conocimiento social sobre la mentira, referido tanto a los escenarios cotidianos donde aparece la mentira, como a las conductas no verbales asociadas a la emisión de la mentira, mediará en la decisión de considerar los mensajes como falsos o verdaderos. Para contrastar esta hipótesis hemos presentado auditivamente información verbal y no verbal que difiere en su grado de coincidencia con tal conocimiento. Los resultados muestran que cuando la información que evalúan los jueces coincide con el conocimiento social de la mentira, tal conocimiento determina los juicios de credibilidad, independientemente de que la información sea verbal o no verbal. Estos resultados cuestionan la orientación de gran número de trabajos dirigidos a dirimir la relevancia de ambos tipos de información para diferenciar entre mensajes falsos y verdaderos (AU)

The present work attempts to increase knowledge about the psychosocial processes that affect the extent to which people believe strangers. Our general hypothesis is that social knowledge about lying will influence the decision to consider their messages as true or false. In order to test this hypothesis we presented verbal (orally) and non-verbal information that differed in their level of agreement with this knowledge. The results show that when the information assessed by the judges coincides with social knowledge about lying, it determines belief judgements, independently of whether the information is verbal or non-verbal. These results call into question the relevance of a great number of studies that concentrate on the differentiation between true and false messages according to their verbal or non-verbal presentation (AU)

Cirugía cardíaca a corazón abierto: experiencia en Mar del Plata / Open heart surgery: experience in Mar del Plata

Se presenta la experiencia inicial en cirugía cardíaca a corazón abierto de un hospital general de 150 camas alejado de un centro universitario. Entre noviembre de 1982 y julio de 1984 fueron operados con circulación extracorpórea 93 pacientes: los 53 coronarios (61,0 años de promedio, 17% mujeres) incluyeron 5 lesiones de tronco y recibieron un promedio de 2,8 puentes por paciente, durante un "clampeo" aórtico promedio de 21 minutos por puente. La protección miocárdica estuvo asegurada por hipotermia general moderada, cardioplejía hipercalémica fría e irrigación continua del pericardio con suero frío. La mortalidad hospitalaria fue del 1,9%. Los 35 valvulares (56,6 años de promedio, 50% mujeres) repartidos en 5 comisurotomías mitrales, 6 reemplazos mitrales aislados, 16 reemplazos aórticos aislados, 4 reemplazos aórticos más puente y 4 dobles reemplazos, recibieron bajo una protección miocárdica similar 19 prótesis mecánicas y 14 biológicas, con una mortalidad hospitalaria del 6% para la cirugía electiva. Cuatro cardiopatías congénitas en el adulto se corrigieron sin mortalidad hospitalaria. La cirugía cardíaca con circulación extracorpórea es posible de ser realizada con buenos resultados con un hospital de las caracteristicas anotadas

Cirugía cardíaca a corazón abierto: experiencia en Mar del Plata / Open heart surgery: experience in Mar del Plata

Se presenta la experiencia inicial en cirugía cardíaca a corazón abierto de un hospital general de 150 camas alejado de un centro universitario. Entre noviembre de 1982 y julio de 1984 fueron operados con circulación extracorpórea 93 pacientes: los 53 coronarios (61,0 años de promedio, 17% mujeres) incluyeron 5 lesiones de tronco y recibieron un promedio de 2,8 puentes por paciente, durante un "clampeo" aórtico promedio de 21 minutos por puente. La protección miocárdica estuvo asegurada por hipotermia general moderada, cardioplejía hipercalémica fría e irrigación continua del pericardio con suero frío. La mortalidad hospitalaria fue del 1,9%. Los 35 valvulares (56,6 años de promedio, 50% mujeres) repartidos en 5 comisurotomías mitrales, 6 reemplazos mitrales aislados, 16 reemplazos aórticos aislados, 4 reemplazos aórticos más puente y 4 dobles reemplazos, recibieron bajo una protección miocárdica similar 19 prótesis mecánicas y 14 biológicas, con una mortalidad hospitalaria del 6% para la cirugía electiva. Cuatro cardiopatías congénitas en el adulto se corrigieron sin mortalidad hospitalaria. La cirugía cardíaca con circulación extracorpórea es posible de ser realizada con buenos resultados con un hospital de las caracteristicas anotadas (AU)