Mie scattering theory applied to light scattering of large nonhomogeneous colloidal spheres.

Colloidal suspensions made of smart core-shell structures are of current interest in many fields. Their properties come from the possibility of varying the core and shell materials for modifying the composite particles' chemical, biological, and optical properties. These particles are formed with a material with a constant refractive index core and a shell with a refractive index decaying until it matches the solvent refractive index. Poly(N-IsoPropyl AcrylaMide) (PNIPAM) is a typical example of materials forming shells. In this report, we present how to apply Mie scattering theory to predict and understand the static light scattering of large nonhomogeneous colloidal particles with spherical symmetry whose size is comparable with or larger than the light wavelength used for developing scattering experiments, where the Rayleigh-Gans-Debye approximation is not valid. Here, the refractive index decay was approximated by a Gaussian RI profile numerically evaluated through a multilayer sphere. We calculated the form factor functions of suspensions of PNIPAM microgels previously reported and core-shell suspensions made of polystyrene/PNIPAM at 20 and 40 °C synthesized by us. In all the cases, our method succeeded in providing the scattering intensity as a function of the angle. The software for using the numerical method is fairly straightforward and is accessible as an open-source code. The results can not only help predict and understand the photonic properties of microgels with large core-shell structures but also for any particle with a refractive index distribution with spherical symmetry, as in the case of microgels with super chaotropic agents, hollow microgels, or microparticles.

Competition among physical, chemical, and hybrid gelation mechanisms in biopolymers.

Depending on how they form their linkages, biopolymer gelatin gels are commonly classified as physical, chemical, or hybrid; in gelatin hybrid gels, the physical and chemical crosslinking mechanisms occur simultaneously. The viscoelastic behavior of gels following different gelation processes was determined around the gel point. Their gel fractal dimensions were obtained using the BST-scaling model from large amplitude oscillatory shear results. The fractal dimension of hybrid gels is between 1.46 and 1.60, depending on the dominant crosslinking process. The main features of the Lissajous-Bowditch curves were determined for maturated gels that follow different gelation processes, and it is possible to observe the dominant gelation mechanism. The gelation kinetics process is followed by measuring the mean squared displacement (MSD) of microspheres embedded in gelatin solutions using diffusion wave spectroscopy, which in turn allows evaluating G'(ω) and G''(ω), the persistence length, and the mesh size as a function of time throughout the gelation process. The MSD, as a function of elapsed time from the start of the gelation process, follows a behavior that depends on the gelation processes. As time elapses after gelation starts, the persistence length of the unstructured, non-bonded flexible polymer sections decreases due to the formation of bonds. In the hybrid case, it is not a mixture of both processes; they are not independent when occurring simultaneously. The time evolution of the gel network's mesh size roughly follows an exponential decay.

Experiencia académica sobre la presentación de trabajos científicos en la IV Conferencia Internacional: Desafíos clínicos y terapéuticos en psicosis / Academic experience on the presentation of scientific papers at the IV International Conference: Clinical and therapeutic challenges in psychosis

Dentro de los desafíos de la investigación en psicosis en Chile y el mundo se encuentra el desarrollo de polos académicos de investigación en estados mentales de riesgo (EMARS). En este artículo se realiza un análisis descriptivo de los trabajos científicos presentados en la IV conferencia internacional: Desafíos Clínicos y terapéuticos en Psicosis realizada en octubre del 2022. Métodos: Se realizó una selección y premiación del mejor trabajo de acuerdo a un sistema de puntuación realizado por un comité científico ad-hoc. Luego se sistematizó la información en una tabla resumen para su posterior análisis descriptivo cualitativo. Resultados: Se seleccionaron 5 trabajos. El 100% de los trabajos seleccionados abordan el tema de la detección precoz e intervención temprana en psicosis, en particular en la temática EMARS. Asimismo, la mayoría de los trabajos presentados provienen de la región metropolitana. El 80% de los trabajos realizan un diseño experimental con reclutamiento de pacientes y el 20% usaron una metodología cualitativa. Conclusión: Así como años anteriores, los trabajos seleccionados dan cuenta de la importancia por el mejoramiento en la prevención, diagnóstico e intervención temprana en Psicosis. Se debe potenciar en Chile y latinoamerica el desarrollo académico y clínico en el campo de los EMARS.

Among the challenges of research in psychosis in Chile and the world, is the development of academic hubs for research in at-risk mental states (ARMS). This article presents a descriptive analysis of the summaries of the scientific works presented at the IV international conference: Clinical and Therapeutic Challenges in Psychosis held in October 2022. Methods: A selection and award were made for the best work according to a scoring system developed by an ad-hoc scientific committee. Then the information was systematized in a summary table for its subsequent qualitative descriptive analysis. Results: 5 works were selected. 100% of the selected works address the issue of early detection and early intervention in psychosis, particularly in the ARMS. Most of the papers presented come from the metropolitan region. 80% of the works carried out an experimental design with patient recruitment and 20% used a qualitative methodology. Conclusion: As in previous years, the selected works show the importance of improving prevention, diagnosis, and early intervention in psychosis. Research and clinical work in Chile and Latinoamerica should be strengthened in the field of ARMS.

Micellar entanglement and its relation to the elastic behavior of wormlike micelle fluids.

HYPOTHESIS: The elastic contribution to the fluid dynamics of wormlike micellar solutions makes these fluids unique due to the distinctive self-assembled micellar network formed by tubular micelles. Measured mesoscopic scales of the micellar network related to the degree of entanglement can give guidelines for understanding the origin of elastic forces and their effect on rheological response. EXPERIMENTS: Different experiments were made as flow curves, rotating the internal or external cylinder in a Couette geometry, small and large oscillatory shear tests, and linear shear banding observations, all of them to determine how elastic forces modify the rheological behavior in systems made of different ratios of hexadecyltrimethylammonium bromide (CTAB)/sodium salicylate (NaSal) and different ratios of CTAB/NaNO3. Diffusive wave spectroscopy micro-rheology was also performed to measure the mean square displacements of microspheres embedded in the micellar fluids to obtain their high-frequency viscoelastic spectra. With this information, the entanglement index κ, the ratio of the total contour of the micelles to the entanglement length, was estimated and correlated with the rheological behavior. FINDINGS: The entanglement index is a valuable piece of information to understand the origin of the contribution of the elastic forces from a molecular point of view on the fluid dynamics of wormlike micelle solutions.

Impacto de la transformación digital en la salud tropical / Impact of digital transformation on tropical health

La Transformación Digital (TD) es todo un proceso que busca optimizar la relación usuario­organización, mejorando así los procesos y el desempeño. Con la llegada de la pandemia COVID-19 a principios del año 2020, cuando fue necesario acelerar la inclusión de las Tecnologías de Información y Comunicación (TIC) para continuar ofreciendo los servicios sanitarios, se constituye el sistema peruano de TD como un sistema funcional; con normas, principios y procedimientos; y con técnicas e instrumentos para ordenar las actividades del sector público y con miras a su optimización. Se planteó una investigación de carácter descriptivo para conocer el impacto de la transformación digital en la salud tropical del Perú. Para ello se determinaron el impacto en la gestión de datos, gobernanza, e intercambio de conocimiento e innovación digital de 4 enfermedades metaxénicas y 3 zoonóticas seleccionadas a partir del análisis de los distintos componentes de la sala virtual de situación de salud del Centro Nacional de Epidemiología, Prevención y Control de Enfermedades del Perú. Los datos fueron analizados bajo el Sistema de Información para la Salud (IS4H) de la OPS que permitió valorar la interoperabilidad de los procesos relacionados con la categorización de estas nosologías. Para todos los factores evaluados: gestión de datos, innovación, gestión y gobernanza y gestión e intercambio de conocimiento, los resultados, en general, estuvieron alrededor de la media (3 puntos, en una escala del 1 al 5), siendo el valor más alto (3,3 puntos) para la gestión y gobernanza, y el valor más bajo (2,7 puntos) para la innovación. Se necesita un enfoque más holístico en la salud pública para asegurarse de que se proporcione una respuesta eficaz frente a las enfermedades tropicales. Si los sistemas de salud se colocan en el medio de la acción, esto permitiría tener mayores posibilidades de hacer frente a estas enfermedades mediante el uso adecuado de las herramientas modernas que logren complementar el enfoque tradiciona(AU)

Digital Transformation (TD) is a whole process that seeks to optimize the user-organization relationship, thus improving processes and performance. With the arrival of the COVID-19 pandemic at the beginning of 2020, when it was necessary to accelerate the inclusion of Information and Communication Technologies (ICT) to continue offering health services, the Peruvian DT system was established as a functional system; with norms, principles and procedures; and with techniques and instruments to order the activities of the public sector and with a view to their optimization. A descriptive investigation was proposed to know the impact of digital transformation on tropical health in Peru. For this, the impact on data management, governance, and exchange of knowledge and digital innovation of 4 metaxenic and 3 zoonotic diseases selected from the analysis of the different components of the virtual health situation room of Centro Nacional de Epidemiología, Prevención y Control de Enfermedades of Peru. The data were analyzed under PAHO's Information System for Health (IS4H), which made it possible to assess the interoperability of the processes related to the categorization of these nosologies. For all the factors evaluated: data management, innovation, management and governance, and knowledge management and exchange, the results, in general, were around the average (3 points, on a scale from 1 to 5), with the highest value being highest (3.3 points) for management and governance, and the lowest value (2.7 points) for innovation. A more holistic approach to public health is needed to ensure that an effective response to tropical diseases is provided. If health systems are placed in the middle of the action, this would allow them to have greater possibilities of dealing with these diseases through the appropriate use of modern tools that manage to complement the traditional approach(AU)

Measuring mesoscopic scales in complex fluids embedded with giant cylindrical micelles with diffusing wave spectroscopy micro-rheology.

This review paper presents a procedure for measuring the mesoscopic scales in micellar solutions embedded with giant cylindrical micelles using the mean square displacement determined with a quasi-elastic multiple light scattering method (diffusing wave spectroscopy) and theory. The mesoscopic scales of interest are the micelles' total contour length, persistence and entanglement lengths, and the mesh size of the entangled micellar network. All of them depend on the physicochemical parameters of the solutions and determine the rheological behavior. We present an assessment of the whole procedure, the scattering experiments performance, the recovery of optical parameters, which includes dealing with the light absorption and its treatment, and how to develop the micro-rheology for obtaining the mesoscopic scales in these complex fluids.

BDNF as a Biomarker of Cognition in Schizophrenia/Psychosis: An Updated Review.

Brain Derived Neurotrophic Factor (BDNF) has been linked to cognitive symptoms of schizophrenia, which has been documented in previous reviews by several authors. However, a trend has recently emerged in this field moving from studying schizophrenia as a disease to studying psychosis as a group. This review article focuses on recent BDNF studies in relation to cognition in human subjects during different stages of the psychotic process, including subjects at high risk of developing psychosis, patients at their first episode of psychosis, and patients with chronic schizophrenia. We aim to provide an update of BDNF as a biomarker of cognitive function on human subjects with schizophrenia or earlier stages of psychosis, covering new trends, controversies, current research gaps, and suggest potential future developments in the field. We found that most of current research regarding BDNF and cognitive symptoms in psychosis is done around schizophrenia as a disease. Therefore, it is necessary to expand the study of the relationship between BDNF and cognitive symptoms to psychotic illnesses of different stages and origins.

Análisis descriptivo de los trabajos científicos presentados en la Segunda Conferencia Internacional Chilena de Psicosis 2020 / Descriptive analysis of the posters abstracts submitted to the Chilean International Conference in Psychosis 2020

INTRODUCCIÓN: Dentro de los desafíos de la investigación en Psicosis en Chile y el mundo se encuentra el desarrollo de polos académicos de investigación en estados mentales de riesgo (EMARS). En este artículo se realiza un análisis descriptivo de los resúmenes de los trabajos científicos presentados en la II conferencia internacional: Desafíos Clínicos y terapéuticos en Psicosis realizada en Octubre del 2020. MÉTODOS: Se realizó una selección y premiación del mejor trabajo de acuerdo a un sistema de puntuación realizado por un comité científico ad-hoc. Luego se sistematizó la información en una tabla resumen para su posterior análisis descriptivo cualitativo. RESULTADOS: Se seleccionaron 12 trabajos. El 75% de los trabajos seleccionados abordan el tema de la detección precoz e intervención temprana en psicosis, en particular en la temática EMARS. Asimismo, el 40% de los trabajos presentados provienen de regiones de la zona centro-sur de nuestro país. El 83% de los trabajos realizan un diseño experimental con reclutamiento de pacientes o discusión de casos clínicos complejos. CONCLUSIÓN: Los trabajos seleccionados dan cuenta del interés por el mejoramiento en el diagnóstico y terapéutica en este ámbito. Se debe potenciar el trabajo de investigación y asistencial en Chile en el ámbito de los EMARS.

INTRODUCTION: Within the challenges of research in Psychosis in Chile and the world is the development of academic research poles in mental states of risk (EMARS). This article makes a descriptive analysis of the summaries of the scientific papers presented at the II international conference: Clinical and therapeutic challenges in Psychosis held in October 2020. METHODS: The best work was selected and awarded according to a scoring system carried out by an ad-hoc scientific committee. The information was then systematized in a summary table for subsequent qualitative descriptive analysis. RESULTS: 12 papers were selected. 75% of the selected works address the issue of early detection and early intervention in psychosis, particularly the EMARS theme. Likewise, 40% of the papers presented come from regions of the south-central zone of our country. 83% of the works carry out an experimental design with recruitment of patients or discussion of complex clinical cases. CONCLUSION: The selected works show the interest in the improvement in diagnosis and therapy in this area. Research and assistance work in Chile should be promoted in the field of EMARS.

Measurement of the capillary interaction force between Janus colloidal particles trapped at a flat air/water interface.

The capillary interaction force between spherical Janus particles trapped at the air-water interface is measured using a time-sharing optical tweezer (bond number ≪ 1). One face of the particles is hydrophilic, and the other one, hydrophobic. Measured force goes from almost pure quadrupolar to almost pure hexapolar interaction due to the three-phase contact line corrugation. Measured force curves are modeled as a sum of power laws, Ar-α + Br-ß + Cr-γ, obtained from an expansion in capillary multipoles. The mean values for the exponents of particle pairs of 3 µm are 〈α〉 = 5.05 ± 0.12, 〈ß〉 = 7.02 ± 0.03, and 〈γ〉 = 5.96 ± 0.03. For particles pairs of 5 µm, we find 〈α〉 = 5.02 ± 0.04, 〈ß〉 = 6.94 ± 0.06, and 〈γ〉 = 5.80 ± 0.05. In both cases, A < 0, B < 0, and C > 0.

Alignment of worm-like micelles at intermediate and high shear rates.

HYPOTHESIS: Rheology combined with Small-Angle Neutron Scattering (Rheo-SANS) can determine the local structural order in Worm-Like Micelle (WLM) solutions when the shear rate increases beyond the ending of the gradient shear banding. There, micelles are supposedly aligned, but viscosity reveals a transition regime as the shear rate increases. EXPERIMENTS: The mixture of 3-[dimethyl(tetradecyl)azaniumyl]propane-1-sulfonate (TDPS), sodium dodecylsulfate (SDS) (R = [SDS]/[TDPS] = 0.55), and a water solution of NaCl (0.2 mol/L), was studied with mechanical rheology and Small-Angle Neutron Scattering (SANS) in the quiescent fluid and under flow. FINDINGS: The system self-assembles in WLMs and presents gradient shear banding. SANS patterns of the bands formed during the shear banding were obtained in a Couette geometry along the 1-2 plane, as well as the orientation parameter along the gap. At very high shear rates, in the paranematic phase, we found an apparent transition on the flow curves with its corresponding change in the orientation parameter. The origin of this transition is unclear, but we present possible explanations of why we observe it.

Mechanical Properties of DPPC-POPE Mixed Langmuir Monolayers.

The mechanical properties of lipid monolayers and their responses to shear and compression stresses play an important role in processes such as breathing and eye blinking. We studied the mechanical properties of Langmuir monolayers of a model mixture, composed of an unsaturated lipid, 1-palmitoyl-2-oleoyl-sn-glycero-phosphoethanolamine (POPE), and a saturated lipid, 1,2-dipalmitoyl-sn-glycero-phosphocholine (DPPC). We performed isothermal compressions and sinusoidal shear deformations of these mixed monolayers. Also, the different phases were observed with Brewster angle microscopy. We found that the mechanical behavior is affected by the miscibility of both lipids. In the two-phase region, the compression elastic modulus increases with the amount of the LC phase but does not follow the predictions of a simple effective medium model. The discrepancies arise from the fact that, upon compression, the domains grow at a rate faster than the compression rate but not fast enough to reach thermodynamic equilibrium. Before reaching the LC phase, domain percolation is observed and compression and shear moduli become equal to those of the pure LC phase. Most of the monolayers behave as viscoelastic fluids at the frequencies investigated. A minimum in the compression modulus and shear viscosity was observed for mixtures close to equimolar composition, with the minimum being accompanied by a change in domain shapes.

Structural Changes in Wormlike Micelles on the Incorporation of Small Photoswitchable Molecules.

Chromophores susceptible to light-induced trans-cis isomerization embedded in cylindrical micelles can modify micelles and their light-responsive performance. A small chromophore (4-(phenylazo)benzoate ion) is embedded in cylindrical micelles made of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) in water. The microstructure is examined by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). Rheological behavior and the length scales of the micellar network are determined by rheology and microrheology. The chromophore substantially modifies the micelles even without UV irradiation. The larger is the chromophore concentration, the smaller is the micellar length. Additional length scales of the micellar network do not substantially vary even when NaCl is added. Chromophore incorporation also modifies the rheology of the micellar solution, although gradient shear banding is preserved. Viscosity decreases as the chromophore concentration increases, and viscoelastic spectra are modified, but when they are correctly rescaled, they can be superimposed. The addition of the chromophore makes the fluids more Maxwellian, particularly when NaCl is also added. When the chromophore is incorporated into the micelles, there is a response after UV irradiation, although it does not produce a significant rheological change.

Alteraciones del Líquido amniótico. Influencia de un folleto Educativo. Manzanillo, 2017 / Alterations of the amniotic fluid. Influence of an educational brochure. Manzanillo 2017

Introducción: el líquido amniótico desempeña un importante papel en el crecimiento y desarrollo fetal. Las alteraciones del volumen del mismo pueden interferir directamente en el desarrollo fetal causando anomalías estructurales como la hipoplasia pulmonar, pueden ser un signo indirecto de un defecto del tubo neural o de anomalías gastrointestinales o de un trastorno fetal como la hipoxia. Objetivo: evaluar los resultados de la aplicación de un folleto educativo en gestantes portadoras de alteraciones del líquido amniótico, durante el período comprendido de julio a diciembre del 2017. Método: se realizó un estudio de intervención educativa en el Hospital Provincial Ginecobstétrico Fe del Valle Ramos del municipio de Manzanillo. El universo de estudio estuvo constituido por 89 gestantes, constituyendo 33 la muestra, las que se seleccionaron a través de un muestreo aleatorio simple y que cumplieran con el criterio de inclusión. Resultados: el grupo de edades que predomina fue el de 25-30 (13), procedente de la zona rural (19) y con un nivel de escolaridad universitario. La enfermedad asociada que más incidió fue la RPM siendo más frecuente en pacientes multíparas, después del parto los recién nacidos que prevalecieron con peso superior a 4000 gr. Antes de aplicar el folleto educativo se mostró un bajo nivel de conocimiento aumentándose el mismo después de aplicado el programa. Conclusiones: el grupo de edades que más aportó fue el de 25 a 29 años, procedentes de la zona rural y con un nivel de escolaridad universitario. La enfermedad asociada que prevaleció fue la rotura prematura de membranas, con 5 pacientes seguida de la diabetes mellitus con 4 casos y en pacientes multíparas, sólo 5 recién nacidos bajo peso(AU)

Introduction: amniotic fluid plays an important role in fetal growth and development. Alterations in its volume can directly interfere with fetal development causing structural abnormalities such as pulmonary hypoplasia, they can be an indirect sign of a neural tube defect or gastrointestinal abnormalities or a fetal disorder such as hypoxia. Objective: to evaluate the results of the application of an educational pamphlet in pregnant women carrying alterations of the amniotic fluid, during the period from July to December 2017. Method: an educational intervention study was carried out at the Fe del Valle Ramos Gyneco-Obstetric Provincial Hospital of the municipality of Manzanillo. The universe of study consisted of 89 pregnant women, constituting 33 the sample, which were selected through a simple random sampling and that met the inclusion criteria. Results:the predominant age group was 25-30 (13), from the rural area (19) and with a level of university education. The associated disease that most affected was the RPM being more frequent in multiparous patients, after birth, those who prevailed were born with a weight greater than 4000 grams. Before applying the educational brochure, a low level of knowledge was shown, increasing it after applying the program. Conclusions: the age group that contributed the most was from 25 to 29 years old, from the rural area and with a level of university education. The associated disease that prevailed was premature rupture of membranes, with 5 patients followed by diabetes mellitus with 4 cases and in multiparous patients, only 5 infants underweight(EU)

Alteraciones del Líquido amniótico. Influencia de un folleto Educativo. Manzanillo 2017 / Alterations of the amniotic fluid. Influence of an educational brochure. Manzanillo 2017 / Alterações do líquido amniótico. Influência de uma brochura educacional.Manzanillo 2017

RESUMEN Introducción: el líquido amniótico desempeña un importante papel en el crecimiento y desarrollo fetal. Las alteraciones del volumen del mismo pueden interferir directamente en el desarrollo fetal causando anomalías estructurales como la hipoplasia pulmonar, pueden ser un signo indirecto de un defecto del tubo neural o de anomalías gastrointestinales o de un trastorno fetal como la hipoxia. Objetivo: evaluar los resultados de la aplicación de un folleto educativo en gestantes portadoras de alteraciones del líquido amniótico, durante el período comprendido de julio a diciembre del 2017. Método: se realizó un estudio de intervención educativa en el Hospital Provincial Ginecobstétrico "Fe del Valle Ramos" del municipio de Manzanillo. El universo de estudio estuvo constituido por 89 gestantes, constituyendo 33 la muestra, las que se seleccionaron a través de un muestreo aleatorio simple y que cumplieran con el criterio de inclusión. Resultados: el grupo de edades que predomina fue el de 25-30 (13), procedente de la zona rural (19) y con un nivel de escolaridad universitario. La enfermedad asociada que más incidió fue la RPM siendo más frecuente en pacientes multíparas, después del parto los recién que prevalecieron nacidos con peso superior a 4000gr.Antes de aplicar el folleto educativo se mostró un bajo nivel de conocimiento aumentándose el mismo después de aplicado el programa. Conclusiones: el grupo de edades que más aportó fue el de 25 a 29 años, procedentes de la zona rural y con un nivel de escolaridad universitario. La enfermedad asociada que prevaleció fue la rotura prematura de membranas, con 5 pacientes seguida de la diabetes mellitus con 4 casos y en pacientes multíparas, sólo 5 recién nacidos bajo peso.

ABSTRACT Introduction: amniotic fluid plays an important role in fetal growth and development. Alterations in its volume can directly interfere with fetal development causing structural abnormalities such as pulmonary hypoplasia, they can be an indirect sign of a neural tube defect or gastrointestinal abnormalities or a fetal disorder such as hypoxia. Objective: to evaluate the results of the application of an educational pamphlet in pregnant women carrying alterations of the amniotic fluid, during the period from July to December 2017. Method: an educational intervention study was carried out at the "Fe del Valle Ramos" Gyneco-Obstetric Provincial Hospital of the municipality of Manzanillo. The universe of study consisted of 89 pregnant women, constituting 33 the sample, which were selected through a simple random sampling and that met the inclusion criteria. Results: the predominant age group was 25-30 (13), from the rural area (19) and with a level of university education. The associated disease that most affected was the RPM being more frequent in multiparous patients, after birth, those who prevailed were born with a weight greater than 4000 grams. Before applying the educational brochure, a low level of knowledge was shown, increasing it after applying the program. Conclusions: the age group that contributed the most was from 25 to 29 years old, from the rural area and with a level of university education. The associated disease that prevailed was premature rupture of membranes, with 5 patients followed by diabetes mellitus with 4 cases and in multiparous patients, only 5 infants underweight.

RESUMO Introdução: o líquido amniótico desempenha um papel importante no crescimento e desenvolvimento fetal. Alterações no seu volume podem interferir diretamente no desenvolvimento fetal, causando anormalidades estruturais, como hipoplasia pulmonar, podem ser um sinal indireto de um defeito no tubo neural ou anormalidades gastrointestinais ou um distúrbio fetal, como hipóxia. Objetivo: avaliar os resultados da aplicação de um panfleto educativo em gestantes portadoras de alterações do líquido amniótico, no período de julho a dezembro de 2017. Método: foi realizado um estudo de intervenção educacional no Hospital Provincial Gyneco-Obstétrico "Fe del Valle Ramos" do município de Manzanillo. O universo de estudo foi constituído por 89 gestantes, constituindo 33 da amostra, as quais foram selecionadas por amostragem aleatória simples e que atendiam aos critérios de inclusão. Resultados: a faixa etária predominante foi de 25 a 30 (13), da zona rural (19) e com nível de instrução universitária, sendo a doença mais afetada a RPM em pacientes multíparas, após o parto os que prevaleceram nasceram com peso superior a 4000 gr. A brochura educacional mostrou um baixo nível de conhecimento aumentando o mesmo após a aplicação do programa. Conclusões: a faixa etária que mais contribuiu foi de 25 a 29 anos, da zona rural e com nível de ensino superior. A doença associada que prevaleceu foi a ruptura prematura de membranas, com 5 pacientes, seguida de diabetes mellitus com 4 casos e em multíparas, apenas 5 crianças abaixo do peso.

Measurement of the force between uncharged colloidal particles trapped at a flat air/water interface.

The radial attraction between microspheres straddling at the air/water interface (Bond number ≪1), whose origin is the irregular shape of the contact line and its concomitant distortion of the water surface, is measured using two light beams of a time-sharing optical tweezer. The colloidal particles used to make the measurements are microspheres made of hydrophobically covered silica to reduce the electrostatic interactions to a minimum. The measured radial force goes as a quadrupolar power law, r-n, with n = 5.02 ± 0.18 and n = 5.04 ± 0.18 for particles of 3 µm and 5 µm, respectively. In both cases, the electrostatic interaction is negligible.

Early psychosis detection program in Chile: A first step for the South American challenge in psychosis research.

AIM: Early detection and intervention (EDI) is a main challenge in psychosis research. The Chilean schizophrenia (SZ) national program has universal support and treatment by law for all SZ patients, but this does not yet extend to earlier stages of illness. Therefore, we have piloted an ultra-high risk (UHR) program to demonstrate the utility and feasibility of this public health approach in Chile. METHODS: We introduce "The University of Chile High-risk Intervention Program," which is the first national EDI program for UHR youths. Longitudinal follow-up included clinical and cognitive assessments, and monitoring of physiological sensory and cognitive indices, through electroencephalographic techniques. RESULTS: We recruited 27 UHR youths over 2 years. About 92.6% met criteria for attenuated psychosis syndrome (APS). Mean Scale of Psychosis-Risk Symptoms (SOPS) ratings in the cohort were 6.9 (SD 4.6) for positive, 9.1 (SD 8.3) for negative, 5.4 (SD 5.3) for disorganized and 6.3 (SD 4.1) for general symptoms. About 14.8% met criteria for comorbid anxiety disorders and 44.4% for mood disorders. Most participants received cognitive behavioural therapy (62.9%) and were prescribed low dose antipsychotics (85.2%). The transition rate to psychosis was 22% within 2 years. CONCLUSIONS: We describe our experience in establishing the first EDI program for UHR subjects in Chile. Our cohort is similar in profile and risk to those identified in higher-income countries. We will extend our work to further optimize psychosocial and preventive interventions, to promote its inclusion in the Chilean SZ national program and to establish a South American collaboration network for SZ research.

Structure, rheology, and microrheology of wormlike micelles made of PB-PEO diblock copolymers.

A diblock copolymer made of poly(1,4-butadiene)-block-polyethylene oxide, with a degree of polymerization of the polybutadiene and polyethylene oxide blocks of 37 and 57, respectively, self-assembles in water as worm-like micelles determined by small angle neutron scattering with an average diameter of ∼12.7 nm, a core radius of ∼2.7 nm, a shell radius of ∼3 nm, and an estimated persistence length of >225 nm. Worm-like micelles of almost the same diblock copolymer, but with a smaller polyethylene oxide block (degree of polymerization 45) were also measured. The worm-like micelles were also observed with negative staining using low energy electron microscopy. The boundary between dilute and semidilute regimes was estimated to be ∼0.8 wt%. The viscoelastic spectra at low and intermediate frequencies do not follow the Maxwell model. These micelles do not present the same rheological behavior of worm-like micelle solutions of conventional surfactants. The slow dynamics of the self-assembly explains this uncommon behavior for the system. Any micellar rearrangement is impeded due to the extremely high hydrophobicity of the polybutadiene block; stress mainly relaxes by the reptation mechanism. Using diffusive wave spectroscopy, we measured the mean square displacement of particles in the micellar solution. From the mean square displacement, we obtained G'(ω) and G''(ω) at high frequencies. |G*| exhibits a power law behavior showing the stress relaxation changes as frequency increases, first dominated by the Rouse-Zimm modes and then by the bending modes of the Kuhn segments. This allowed us to estimate the worm-like micelle persistence lengths that depend on the copolymer concentration.

Bilayers of Janus and homogeneous particle mixtures trapped at an air/water interface.

We study mixtures of amphiphilic Janus and homogeneous hydrophobic particles trapped at an air/water interface. In contrast to an expected monolayer formation, bilayers of colloidal particles are produced. Despite their strong interfacial adsorption, Janus particles form the upper layer. They are not placed on top of the other particles but rather shifted about one-third of the particle diameter. To understand the mechanism of bilayer formation, particle behaviour at the surface and in the bulk of the spreading solvent is considered. The vertical shift and the bilayer formation are assisted by the momentous formation of two interfaces during spreading.

Tuning the Viscoelastic-Gel Transition of Single-Wall Carbon Nanotubes Embedded in pH-Responsive Polyelectrolyte Solutions.

We present the detailed rheological changes that occur when small quantities of single-wall carbon nanotubes are dispersed in a poly(acrylic acid) water solution, around the overlap polymer concentration, up to the gel point. Here, pH is used to tune the gel formation. Suspensions of nanotubes at pH ≤ 5 are exfoliated and dispersed by the polymer. Contacts between the nanotubes are mainly through polymer entangling, and the suspension is viscoelastic. At pH > 5, the polymer is charged, and the solution is not a good solvent for the nanotubes anymore. Nanotube bundles covered with polymer are formed and mechanically percolate along the fluid until they become arrested. As a consequence, the rheological behavior is dominated by a mesoscale superstructure formed by nanotubes and polymer, where viscoelasticity is lost and the suspension becomes elastic. At pH ≥ 9, the surroundings for the nanotubes are worse, bundles and flocs grow to a larger extent, and they can be observable by scanning microscopies. When the suspension becomes a critical gel, the relaxation moduli can be modeled by a power law in the frequency domain in agreement with the model developed by Winter and co-workers.

Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe.

We present a procedure to perform and interpret pull-off force measurements during the jump-off-contact process between a liquid drop and rough surfaces using a conventional atomic force microscope. In this method, a micrometric liquid mercury drop is attached to an AFM tipless cantilever to measure the force required to pull this drop off a rough surface. We test the method with two surfaces: a square array of nanometer-sized peaks commonly used for the determination of AFM tip sharpness and a multi-scaled rough diamond surface containing sub-micrometer protrusions. Measurements are carried out in a nitrogen atmosphere to avoid water capillary interactions. We obtain information about the average force of adhesion between a single peak or protrusion and the liquid drop. This procedure could provide useful microscopic information to improve our understanding of wetting phenomena on rough surfaces.