Papel de la ecografía en el paciente crítico con ECMO / Role of ultrasound in the critical ill patient with ECMO

La ecografía es un instrumento diagnóstico fundamental en el paciente crítico con membrana de oxigenación extracorpórea (ECMO). Con ella podemos hacer una evaluación anatómica y funcional (cardiaca, pulmonar y vascular) para plantear una adecuada configuración; además, guía su implante, ayuda en la monitorización clínica y la detección de complicaciones, facilita su retirada y completa la evaluación postimplante. En los pacientes con ECMO como soporte respiratorio (veno-venosa), la ecografía torácica permite monitorizar la evolución de la enfermedad pulmonar y la ecocardiografía la evaluación de la función biventricular, especialmente la derecha, y el gasto cardiaco para optimizar el transporte de oxígeno. En la ECMO como soporte circulatorio (veno-arterial), la ecocardiografía supone la guía de la monitorización hemodinámica, permite detectar las principales complicaciones y ayuda al destete del dispositivo. En los equipos ECMO, para un adecuado manejo de estos pacientes, debe haber intensivistas entrenados y con conocimientos avanzados sobre esta técnica. (AU)

Ultrasound is an essential diagnostic tool in critically ill patients with extracorporeal membrane oxygenation (ECMO). With it, we can make an anatomical and functional (cardiac, pulmonary and vascular) evaluation which allows us to execute an adequate configuration, guides implantation, helps clinical monitorization and detects complications, facilitates withdrawal and complete post-implant evaluation. In patients with ECMO as respiratory support (veno-venous), thoracic ultrasound allows monitoring pulmonary illness evolution and echocardiography the evaluation of biventricular function, especially right ventricle function, and cardiac output to optimize oxygen transport. In ECMO as circulatory support (veno-arterial), echocardiography is the guide of hemodynamic monitoring, allows detecting the most frequent complications and helps the weaning. In ECMO teams, for a proper management of these patients, there must be trained intensivists with advanced knowledge on this technique. (AU)

Role of ultrasound in the critical ill patient with ECMO.

Ultrasound is an essential diagnostic tool in critically ill patients with extracorporeal membrane oxygenation (ECMO). With it, we can make an anatomical and functional (cardiac, pulmonary and vascular) evaluation which allows us to execute an adequate configuration, guides implantation, helps clinical monitorization and detects complications, facilitates withdrawal and complete post-implant evaluation. In patients with ECMO as respiratory support (veno-venous), thoracic ultrasound allows monitoring pulmonary illness evolution and echocardiography the evaluation of biventricular function, especially right ventricle function, and cardiac output to optimize oxygen transport. In ECMO as circulatory support (veno-arterial), echocardiography is the guide of hemodynamic monitoring, allows detecting the most frequent complications and helps the weaning. In ECMO teams, for a proper management of these patients, there must be trained intensivists with advanced knowledge on this technique.

Ecografía abdominal básica en medicina intensiva y VExUS Score / Abdominal ultrasound and VExUS score in critical care

El uso de la ecografía en las unidades de críticos se ha extendido de forma exponencial en las últimas dos décadas y se ha convertido en una parte esencial de nuestra práctica clínica. La ecografía abdominal es una técnica ampliamente establecida en otras especialidades, pero su uso en cuidados intensivos ha quedado rezagado respecto a otras modalidades de ecografía. Sin embargo, su potencial papel en el diagnóstico y manejo de los pacientes lo convertirá en una herramienta invaluable para los intensivistas. El uso más extendido de la ecografía abdominal a pie de cama es para la valoración de la presencia de líquido libre en el paciente traumático. No obstante, la ecografía abdominal también puede ayudarnos a diagnosticar pacientes con dolor abdominal, hipovolemia o anuria, y puede guiarnos en procedimientos como la paracentesis o el sondaje vesical o gástrico. (AU)

The use of ultrasound while caring for critically ill patients has been increasing exponentially in the last two decades and now is an essential component of intensive care practice. Abdominal ultrasound is an established technique in other specialties, but its use in intensive care has lagged behind other ultrasound modalities. However, its potential role in the diagnosis and management of patients will make it an invaluable tool for intensivists. The main use of abdominal ultrasound at the bedside is for free fluid detection in trauma patients. But abdominal ultrasound can also help us diagnose patients with abdominal pain, hypovolemia or anuria, and it can guide us during procedures such as paracentesis or bladder catheter and gastric tube placement. (AU)

Cistoadenoma mucinoso biliar: Un reto diagnóstico / Mucinous biliary cystadenoma: A diagnostic challenge

Introducción. El cistoadenoma mucinoso biliar es una neoplasia rara con alta probabilidad de malignidad. Su diagnóstico es un reto ya que se asemeja a otras masas benignas que pueden encontrarse en el hígado. Caso clínico. Mujer de 21 años con sensación de masa en hipocondrio derecho, a quien se le realizan marcadores tumorales y estudios de imágenes concluyendo que se trataba de un cistadenoma mucinoso biliar. Resultado. Se presenta el caso de una paciente con cistoadenoma mucinoso biliar, diagnosticada y tratada exitosamente con cirugía. Conclusión. El diagnóstico de cistoadenoma mucinoso biliar se confirma mediante marcadores tumorales y estudios radiológicos, y su tratamiento es quirúrgico debido al riesgo de malignidad

Introduction. Biliary mucinous cystadenoma is a rare neoplasm with a high probability of malignancy. Its diagnosis is a challenge since it resembles other benign masses that can be found in the liver. Clinical case. A 21-year-old woman with a sensation of a mass in the right hypochondrium, who underwent tumor markers and imaging studies, concluding with a diagnosis of biliary mucinous cystadenoma. Result. A case of a patient with biliary mucinous cystadenoma diagnosed and successfully treated by surgery is presented. Conclusion. The diagnosis of biliary mucinous cystadenoma is confirmed by tumor markers and radiological studies, and its treatment is surgical due to the risk of malignancy

Genetic profile in patients with complicated acute aortic syndrome: the GEN-AOR study.

INTRODUCTION AND OBJECTIVES: Genetic testing is becoming increasingly important for diagnosis and personalized treatments in aortopathies. Here, we aimed to genetically diagnose a group of acute aortic syndrome (AAS) patients consecutively admitted to an intensive care unit and to explore the clinical usefulness of AAS-associated variants during treatment decision-making and family traceability. METHODS: We applied targeted next-generation sequencing, covering 42 aortic diseases genes in AAS patients with no signs consistent with syndromic conditions. Detected variants were segregated by Sanger sequencing in available family members. Demographic features, risk factors and clinical symptoms were statistically analyzed by Fisher or Fisher-Freeman-Halton Exact tests, to assess their relationship with genetic results. RESULTS: Analysis of next-generation sequencing data in 73 AAS patients led to the detection of 34 heterozygous candidate variants in 14 different genes in 32 patients. Family screening was performed in 31 relatives belonging to 9 families. We found 13 relatives harboring the family variant, of which 10 showed a genotype compatible with the occurrence of AAS. Statistical tests revealed that the factors associated with a positive genetic diagnosis were the absence of hypertension, lower age, family history of AAS and absence of pain. CONCLUSIONS: Our findings broaden the spectrum of the genetic background for AAS. In addition, both index patients and studied relatives benefited from the results obtained, establishing the most appropriate level of surveillance for each group. Finally, this strategy could be reinforced by the use of stastistically significant clinical features as a predictive tool for the hereditary character of AAS. CLINICALTRIALS: gov (Identifier: NCT04751058).

Abdominal ultrasound and VExUS score in critical care.

The use of ultrasound while caring for critically ill patients has been increasing exponentially in the last two decades and now is an essential component of intensive care practice. Abdominal ultrasound is an established technique in other specialties, but its use in intensive care has lagged behind other ultrasound modalities. However, its potential role in the diagnosis and management of patients will make it an invaluable tool for intensivists. The main use of abdominal ultrasound at the bedside is for free fluid detection in trauma patients. But abdominal ultrasound can also help us diagnose patients with abdominal pain, hypovolemia or anuria, and it can guide us during procedures such as paracentesis or bladder catheter and gastric tube placement.

Estrategia didáctico-metodológica para contribuir a la preparación idiomática de los profesionales de Enfermería / Didactic-methodological strategy to contribute to the language preparation of Nursing professionals

Fundamento: la preparación idiomática de los profesionales de Enfermería para enfrentar los retos que representa asumir la colaboración en países de habla inglesa. Objetivo: determinar la efectividad de una estrategia didáctico-metodológica de integración para elevar la competencia comunicativa de profesionales de la Enfermería, en la colaboración internacional en países de habla inglesa. Métodos: investigación de tipo prexperimento realizada en la Universidad de Ciencias Médicas de Villa Clara, entre enero 2022-abril 2023. Se utilizaron métodos teóricos: análisis-síntesis, inductivo-deductivo; histórico-lógico y sistémico-estructural; empíricos: análisis documental, observación, entrevista, entrevista grupal, prueba pedagógica, y matemático-estadísticos. Resultados: en el análisis documental del programa de los posgrados se pudo constatar que no integran armónicamente los postulados del Marco Común Europeo de Referencia para las Lenguas, la inmersión lingüística y el aprendizaje acelerado así como la combinación de las estructuras del inglés general con el inglés con propósitos específicos. La entrevista grupal con los docentes analizó el bajo nivel de asimilación de 20 cursistas, lo que llevó a hacer un grupo especial, el examen de entrada mostró que alrededor del 90 % de los alumnos comenzó el curso sin vencer el nivel A1; sin embargo, los resultados el examen de salida mostraron que más del 70 % concluyó con un nivel B1 plus. Conclusiones: la estrategia didáctico-metodológica para contribuir a elevar la preparación idiomática de los profesionales de Enfermería contribuyó satisfactoriamente con la preparación idiomática de los cursistas.

Background: the language preparation of Nursing professionals to face the challenges of assuming collaboration in English-speaking countries. Objective: determine the effectiveness of a didactic-methodological integration strategy to increase the communicative competence of nursing professionals, in international collaboration in English-speaking countries. Methods: pre-experiment type research carried out at the Villa Clara University of Medical Sciences, from January 2022 to April 2023. Theoretical methods were used: analysis-synthesis, inductive-deductive; historical-logical and systemic-structural; empirical ones: documentary analysis, observation, interview, group interview, pedagogical test, and mathematical-statistical. Results: in the documentary analysis of the postgraduate program, it was found that they do not harmoniously integrate the postulates of the Common European Framework of Reference for Languages, linguistic immersion and accelerated learning, as well as the combination of the structures of general English with English for specific purposes. The group interview with the teachers analyzed the low level of assimilation of 20 students, which led to creating a special group. The pre- test exam showed that around 90% of the students began the course without passing level A1; however, the results of the post-test exam showed that more than 70% concluded with a B1 plus level. Conclusions: the didactic-methodological strategy to help raise the language preparation of Nursing professionals contributed satisfactorily to the language preparation of the students.

Sampling errors and variability in video transects for assessment of reef fish assemblage structure and diversity.

Video monitoring is a rapidly evolving tool in aquatic ecological research because of its non-destructive ability to assess fish assemblages. Nevertheless, methodological considerations of video monitoring techniques are often overlooked, especially in more complex sampling designs, causing inefficient data collection, processing, and interpretation. In this study, we discuss how video transect sampling designs could be assessed and how the inter-observer variability, design errors and sampling variability should be quantified and accounted for. The study took place in the coastal areas of the Galapagos archipelago and consisted of a hierarchical repeated-observations sampling design with multiple observers. Although observer bias was negligible for the assessment of fish assemblage structure, diversity and counts of individual species, sampling variability caused by simple counting/detection errors, observer effects and instantaneous fish displacement was often important. Especially for the counts of individual species, sampling variability most often exceeded the variability of the transects and sites. An extensive part of the variability in the fish assemblage structure was explained by the different transects (13%), suggesting that a sufficiently high number of transects is required to account for the within-location variability. Longer transect lengths allowed a better representation of the fish assemblages as sampling variability decreased by 33% if transect length was increased from 10 to 50 meters. However, to increase precision, including more repeats was typically more efficient than using longer transect lengths. The results confirm the suitability of the technique to study reef fish assemblages, but also highlight the importance of a sound methodological assessment since different biological responses and sampling designs are associated with different levels of sampling variability, precision and ecological relevance. Therefore, besides the direct usefulness of the results, the procedures to establish them may be just as valuable for researchers aiming to optimize their own sampling technique and design.

Efficient Tandem Quantum-Dot LEDs Enabled by An Inorganic Semiconductor-Metal-Dielectric Interconnecting Layer Stack.

Light-emitting diodes (LEDs) in a tandem configuration offer a strategy to realize high-performance, multicolor devices. Until now, though, the efficiency of tandem colloidal quantum dot LEDs (QLEDs) has been limited due to unpassivated interfaces and solvent damage originating from the materials processing requirements of interconnecting layers (ICLs). Here an ICL is reported consisting of a semiconductor-metal-dielectric stack that provides facile fabrication, materials stability, and good optoelectronic coupling. It is investigated experimentally how the ICL enables charge balance, suppresses current leakage, and prevents solvent damage to the underlying layers. As a result record efficiencies are reported for double-junction tandem QLEDs, whose emission wavelengths cover from blue to red light; i.e., external quantum efficiencies (EQEs) of 40% (average 37+/-2%) for red, 49% (average 45+/-2%) for yellow, 50% (average 46+/-2%) for green, and 24% (average 21+/-2%) for blue are achieved.

Multication perovskite 2D/3D interfaces form via progressive dimensional reduction.

Many of the best-performing perovskite photovoltaic devices make use of 2D/3D interfaces, which improve efficiency and stability - but it remains unclear how the conversion of 3D-to-2D perovskite occurs and how these interfaces are assembled. Here, we use in situ Grazing-Incidence Wide-Angle X-Ray Scattering to resolve 2D/3D interface formation during spin-coating. We observe progressive dimensional reduction from 3D to n = 3 → 2 → 1 when we expose (MAPbBr3)0.05(FAPbI3)0.95 perovskites to vinylbenzylammonium ligand cations. Density functional theory simulations suggest ligands incorporate sequentially into the 3D lattice, driven by phenyl ring stacking, progressively bisecting the 3D perovskite into lower-dimensional fragments to form stable interfaces. Slowing the 2D/3D transformation with higher concentrations of antisolvent yields thinner 2D layers formed conformally onto 3D grains, improving carrier extraction and device efficiency (20% 3D-only, 22% 2D/3D). Controlling this progressive dimensional reduction has potential to further improve the performance of 2D/3D perovskite photovoltaics.

Polluted paradise: Occurrence of pesticide residues within the urban coastal zones of Santa Cruz and Isabela (Galapagos, Ecuador).

Although pesticides are frequently used for agriculture in the Galapagos Islands (Ecuador), there are, to date, no investigations of pesticide occurrences in its coastal waters. We examined the presence of pesticide residues in the coastal waters of urban areas in two islands of the Galapagos archipelago using a repeated sampling design. Quantification was performed by solid-phase extraction, followed by chemical analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-electron capture detector (GC-ECD). The diversity and concentration of pesticide residues in Santa Cruz island were higher compared to Isabela island. In total, sixteen pesticides were detected, including three persistent organic pollutants. Carbendazim (23.93 µg·L-1), cadusafos (4.74 µg·L-1), DDT (2.99 µg·L-1), diuron (1.61 µg·L-1) and aldrin (1.55 µg·L-1) were detected with the highest concentrations between samples. Repetitions in locations show that concentrations of pesticide residues varied considerably in space and time. Comparison with local products indicated agricultural activities on the islands as a possible source. Furthermore, evaluation through ecological risk quotients showed that the observed concentration levels of seven pesticides pose a relatively high risk for three biotic groups (i.e. algae, invertebrates and fishes). Taken together, this study provides insights into the need to regulate, monitor and assess the presence of pesticides in the islands. At a global scale, this study is moreover valuable for the many islands that are facing the same challenges.

Una experiencia docente investigativa con estudiantes de tercer año de Licenciatura en Nutrición / Teaching and research experiences from third year undergraduate students in Nutrition

RESUMEN Fundamento: la educación superior cubana prioriza el desarrollo de la lengua materna entre sus estudiantes, quienes en ocasiones muestran carencias cognoscitivas e insuficientes habilidades lingüísticas. Objetivo: explicar una experiencia docente investigativa vinculada al desarrollo de la lengua materna, desde el programa "Ortografía y Gramática" para alumnos de tercer año de Licenciatura en Nutrición. Métodos: se realizó un estudio cualitativo en la Facultad de Tecnología-Enfermería en la Universidad de Ciencias Médicas de Villa Clara, durante el periodo septiembre-noviembre de 2019. Paralelamente a los métodos y procedimientos pedagógicos utilizados en la impartición del programa, se emplearon métodos teóricos: análisis-síntesis e inducción-deducción para obtener, procesar y analizar la información. La revisión documental -método empírico fundamental- el análisis del discurso y el método matemático, propiciaron el arribo a conclusiones confiables. Resultados: el diagnóstico realizado permitió explorar acerca del estado cognoscitivo y las habilidades ortográficas, gramaticales y de redacción de los estudiantes a partir de la revisión de trabajos escritos por ellos; el programa fue impartido empleando técnicas indagatorias que se transformaron en experiencias positivas ya que a pesar de su poca duración los resultados finales demostraron lo acertado de su aplicación. Conclusiones: la experiencia pedagógica propició que los alumnos se involucraran conscientemente en un proceso donde sistematizaron habilidades propias de la lengua materna casi perdidas, y adquirieron y reafirmaron contenidos usando una bibliografía actualizada y adecuada a sus carencias y las necesidades del programa.

ABSTRACT Background: Cuban higher education prioritizes the development of mother tongue among students. Sometimes cognitive deficiencies and lack of language skills can be perceived in expressing themselves. Objective: to explain teaching and research experiences linked to the development of mother tongue, based on the "Ortografía Gramática" for third year students studying Bachelor's Degree in Nutrition. Methods: a qualitative study was carried out in the Tecnology and Nursing Faculty at the University of Medical Sciences of Villa Clara, from September to November 2019. In the same way that pedagogical methods and procedures were used in the program delivery, theoretical methods were also used: analysis-synthesis and induction-deduction methods to collect, process and analyze the information. Documentary review - a basic empirical method - speech analysis and the mathematical method favoured we draw valid conclusions. Results: diagnostic tests resulted in searching for the cognitive state and students' orthographic, grammatical and writing skills taking as reference papers written by them; the program was taught by using exploratory techniques that became into positive experiences since the final results proved its successful application even though the program was taught in a very short time. Conclusions: pedagogical experience brought students to consciously engage in a process through which they could systematize the almost lost mother tongue skills, and they learned and consolidated content using an updated and appropriate bibliography according to their shortcomings and the program needs.

Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots.

Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids-necessary for device fabrication-requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V-1 s-1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%.

The potential of fatty acid isotopes to trace trophic transfer in aquatic food-webs.

Compound-specific isotope analyses (CSIA) of fatty acids (FA) constitute a promising tool for tracing energy flows in food-webs. However, past applications of FA-specific carbon isotope analyses have been restricted to a relatively coarse food-source separation and mainly quantified dietary contributions from different habitats. Our aim was to evaluate the potential of FA-CSIA to provide high-resolution data on within-system energy flows using algae and zooplankton as model organisms. First, we investigated the power of FA-CSIA to distinguish among four different algae groups, namely cyanobacteria, chlorophytes, haptophytes and diatoms. We found substantial within-group variation but also demonstrated that δ13C of several FA (e.g. 18:3ω3 or 18:4ω3) differed among taxa, resulting in group-specific isotopic fingerprints. Second, we assessed changes in FA isotope ratios with trophic transfer. Isotope fractionation was highly variable in daphnids and rotifers exposed to different food sources. Only δ13C of nutritionally valuable poly-unsaturated FA remained relatively constant, highlighting their potential as dietary tracers. The variability in fractionation was partly driven by the identity of food sources. Such systematic effects likely reflect the impact of dietary quality on consumers' metabolism and suggest that FA isotopes could be useful nutritional indicators in the field. Overall, our results reveal that the variability of FA isotope ratios provides a substantial challenge, but that FA-CSIA nevertheless have several promising applications in food-web ecology. This article is part of the theme issue 'The next horizons for lipids as 'trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.

Mechanisms of LiF Interlayer Enhancements of Perovskite Light-Emitting Diodes.

The use of LiF as a thin interlayer between the electron transport layer and cathode has played a pivotal role in remarkable advances in perovskite LEDs (PeLEDs); however, the mechanism behind the effect of LiF remains to be fully understood. Here, we report a combined experimental and computational study, from which we ascribe the benefits of a LiF interlayer to the migration of dissociated Li into the cathode and dissociated F into the anode. Electronic device simulations reveal that the former improves electron injection by lowering the Schottky barrier height, while the latter reduces the barrier width. These reduce turn-on voltage and improve current density and charge balance in LEDs. We fabricate PeLEDs with and without the LiF interlayer and link these materials and electronic phenomena to the device light-current-voltage characteristics. X-ray photoelectron spectroscopy obtained in sputter profiling of PeLEDs corroborates the dissociation of LiF.

Directional Light Emission from Layered Metal Halide Perovskite Crystals.

Metal halide perovskites are being increasingly explored for use in light-emitting diodes (LEDs), with achievements in efficiency and brightness charted across the spectrum. One path to further boosting the fraction of useful photons generated by injected electrical charges will be to tailor the emission patterns of devices. Here we investigate directional emission from layered metal halide perovskites. We quantify the proportion of in-plane versus out-of-plane transition dipole components for a suite of layered perovskites. We find that certain perovskite single crystals have highly anisotropic emissions and up to 90% of their transition dipole in-plane. For thin films, emission anisotropy increases as the nominal layer thickness decreases and is generally greater with butylammonium cations than with phenethylammonium cations. Numerical simulations reveal that anisotropic emission from layered perovskites in thin-film LEDs may lead to external quantum efficiencies of 45%, an absolute gain of 13% over equivalent films with isotropic emitters.

Chloride Insertion-Immobilization Enables Bright, Narrowband, and Stable Blue-Emitting Perovskite Diodes.

Metal halide perovskites show promise for light-emitting diodes (LEDs) owing to their facile manufacture and excellent optoelectronic performance, including high color purity and spectral stability, especially in the green region. However, for blue perovskite LEDs, the emission spectrum line width is broadened to over 25 nm by the coexistence of multiple reduced-dimensional perovskite domains, and the spectral stability is poor, with an undesirable shift (over 7 nm) toward longer wavelengths under operating conditions, degradation that occurs due to phase separation when mixed halides are employed. Here we demonstrate chloride insertion-immobilization, a strategy that enables blue perovskite LEDs, the first to exhibit narrowband (line width of 18 nm) and spectrally stable (no wavelength shift) performance. We prepare bromide-based perovskites and then employ organic chlorides for dynamic treatment, inserting and in situ immobilizing chlorides to blue-shift and stabilize the emission. We achieve sky-blue LEDs with a record luminance over 5100 cd/m2 at 489 nm, and an operating half-life of 51 min at 1500 cd/m2. By device structure optimization, we further realize an improved EQE of 5.2% at 479 nm and an operating half-life of 90 min at 100 cd/m2.

Right Ventricular Assist Devices After Heart Transplantation.

BACKGROUND: Severe right ventricular failure (RVF) has a significant incidence among cardiac transplant patients. It is a serious complication and an independent risk factor for postoperative mortality. In this setting, ventricular assist devices (VADs) must be considered if conservative medical management fails. This study sought to examine our series of patients with early RVF after heart transplantation requiring VAD support. METHOD: We analyzed consecutive, adult heart transplant recipients at a third level intensive care unit who underwent transplantation from January 2011 to March 2019 requiring post-transplant mechanical circulatory support for RVF. Demographic characteristics, clinical data, complications, and survival rates were collected. RESULTS: Ten patients were included. Median age was 50 years (range, 31.7-57). Eight patients (80%) were male. The most frequent indication for heart transplantation was ischemic heart disease (4 patients) followed by dilated cardiomyopathy and congenital heart disease (2 patients). Preoperative pulmonary hypertension was present in 6 patients. Three patients required a VAD before transplant. Whole survival rate was 60%. After heart transplantation, 7 patients required renal replacement therapy, 2 patients suffered a hemorrhagic stroke, and 5 patients needed a tracheostomy for long-term ventilation. CONCLUSION: Patients who develop RVF after transplantation have an increased incidence of complications and high mortality after surgery. VADs could be implanted immediately after heart transplantation in high-risk patients.

Multi-cation perovskites prevent carrier reflection from grain surfaces.

The composition of perovskite has been optimized combinatorially such that it often contains six components (AxByC1-x-yPbXzY3-z) in state-of-art perovskite solar cells. Questions remain regarding the precise role of each component, and the lack of a mechanistic explanation limits the practical exploration of the large and growing chemical space. Here, aided by transient photoluminescence microscopy, we find that, in perovskite single crystals, carrier diffusivity is in fact independent of composition. In polycrystalline thin films, the different compositions play a crucial role in carrier diffusion. We report that methylammonium (MA)-based films show a high carrier diffusivity of 0.047 cm2 s-1, while MA-free mixed caesium-formamidinium (CsFA) films exhibit an order of magnitude lower diffusivity. Elemental composition studies show that CsFA grains display a graded composition. This curtails electron diffusion in these films, as seen in both vertical carrier transport and surface potential studies. Incorporation of MA leads to a uniform grain core-to-edge composition, giving rise to a diffusivity of 0.034 cm2 s-1 in CsMAFA films. A model that invokes competing crystallization processes allows us to account for this finding, and suggests further strategies to achieve homogeneous crystallization for the benefit of perovskite optoelectronics.

Edge stabilization in reduced-dimensional perovskites.

Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97 ± 3% photoluminescence quantum yields and stabilities that exceed 300 h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000 cd m-2; their maximum luminance is 4.5 × 104 cd m-2 (corresponding to an EQE of 5%); and, at 4000 cd m-2, they achieve an operational half-lifetime of 3.5 h.