Enhancing Circularly Polarized Electroluminescence through Energy Transfer within a Chiral Polymer Host.

Organic light-emitting diodes (OLEDs) that are able to emit high levels of circularly polarized (CP) light hold significant promise in numerous future technologies. Such devices require chiral emissive materials to enable CP electroluminescence. However, the vast majority of current OLED emitter classes, including the state-of-the-art triplet-harvesting Thermally Activated Delayed Fluorescence (TADF) materials, produce very low levels of CP electroluminescence. Here we showcase a host-guest strategy that allows for energy transfer between a chiral polymer host and a representative chiral TADF emitter. Such a mechanism results in large amplification of the circular polarization of the emitter. As such, this study presents a promising avenue to further boost the performance of CP-OLED devices, enabling their further development and eventual commercialization. This article is protected by copyright. All rights reserved.

An innovative technological infrastructure for managing SARS-CoV-2 data across different cohorts in compliance with General Data Protection Regulation.

Background: The ORCHESTRA project, funded by the European Commission, aims to create a pan-European cohort built on existing and new large-scale population cohorts to help rapidly advance the knowledge related to the prevention of the SARS-CoV-2 infection and the management of COVID-19 and its long-term sequelae. The integration and analysis of the very heterogeneous health data pose the challenge of building an innovative technological infrastructure as the foundation of a dedicated framework for data management that should address the regulatory requirements such as the General Data Protection Regulation (GDPR). Methods: The three participating Supercomputing European Centres (CINECA - Italy, CINES - France and HLRS - Germany) designed and deployed a dedicated infrastructure to fulfil the functional requirements for data management to ensure sensitive biomedical data confidentiality/privacy, integrity, and security. Besides the technological issues, many methodological aspects have been considered: Berlin Institute of Health (BIH), Charité provided its expertise both for data protection, information security, and data harmonisation/standardisation. Results: The resulting infrastructure is based on a multi-layer approach that integrates several security measures to ensure data protection. A centralised Data Collection Platform has been established in the Italian National Hub while, for the use cases in which data sharing is not possible due to privacy restrictions, a distributed approach for Federated Analysis has been considered. A Data Portal is available as a centralised point of access for non-sensitive data and results, according to findability, accessibility, interoperability, and reusability (FAIR) data principles. This technological infrastructure has been used to support significative data exchange between population cohorts and to publish important scientific results related to SARS-CoV-2. Conclusions: Considering the increasing demand for data usage in accordance with the requirements of the GDPR regulations, the experience gained in the project and the infrastructure released for the ORCHESTRA project can act as a model to manage future public health threats. Other projects could benefit from the results achieved by ORCHESTRA by building upon the available standardisation of variables, design of the architecture, and process used for GDPR compliance.

Evaluating Vascular Depth-Dependent Changes in Multi-Wavelength PPG Signals Due to Contact Force.

Photoplethysmography (PPG) is a non-invasive method used for cardiovascular monitoring, with multi-wavelength PPG (MW-PPG) enhancing its efficacy by using multiple wavelengths for improved assessment. This study explores how contact force (CF) variations impact MW-PPG signals. Data from 11 healthy subjects are analyzed to investigate the still understudied specific effects of CF on PPG signals. The obtained dataset includes simultaneous recording of five PPG wavelengths (470, 525, 590, 631, and 940 nm), CF, skin temperature, and the tonometric measurement derived from CF. The evolution of raw signals and the PPG DC and AC components are analyzed in relation to the increasing and decreasing faces of the CF. Findings reveal individual variability in signal responses related to skin and vasculature properties and demonstrate hysteresis and wavelength-dependent responses to CF changes. Notably, all wavelengths except 631 nm showed that the DC component of PPG signals correlates with CF trends, suggesting the potential use of this component as an indirect CF indicator. However, further validation is needed for practical application. The study underscores the importance of biomechanical properties at the measurement site and inter-individual variability and proposes the arterial pressure wave as a key factor in PPG signal formation.

n-Type Fullerene-Carbon Dots: Synthesis and Electrochemical and Photophysical Properties.

The covalent incorporation of C60 and C70 derivatives of the well-known n-type organic semiconductor PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) onto carbon dots (CD) is described. Morphological and structural characterization reveal combined features of both pristine starting materials (CD and PCBM). Electrochemical investigations evidenced the existence of additional reduction processes to that of CD or PCBM precursors, showing rich electron-acceptor capabilities, with multistep processes in an affordable and narrow electrochemical window (ca. 1.5 V). Electronic communication in the obtained nanoconjugated species were derived from steady-state absorption and emission spectroscopies, which showed bathochromically shifted absorptions and emissions well entering the red region. Finally, the lower fluorescence quantum yield of CD-PCBM nanoconjugates, compared with CD, and the fast decay of the observed emission of CD, support the existence of an electronic communication between both CD and PCBM units in the excited state.

Primary Anorectal Melanoma: Case Report and Review of a Rare Neoplasm

Primary anorectal melanoma is a rare malignant melanocytic neoplasm; its principal manifestation is rectal bleeding. It has an ominous prognosis with a five-year survival rate of 10%. The case of a 56-year-old woman with rectal bleeding and the sensation of a rectal mass is presented. A polypoid lesion, resected transanally, was documented in the distal rectum during the colonoscopy. The histological study confirmed a primary anorectal melanoma.

El melanoma anorrectal primario es una neoplasia melanocítica maligna poco frecuente, su principal manifestación es el sangrado rectal. Tiene un pronóstico ominoso con una tasa de sobrevida del 10% a 5 años. Se presenta el caso de una mujer de 56 años con rectorragia y sensación de masa rectal. Durante la colonoscopia se documentó una lesión polipoide en el recto distal, que se resecó por vía transanal. El estudio histológico confirmó la presencia de un melanoma anorrectal primario.

[Start of enteral nutrition after an endoscopic gastrostomy, is it necessary to wait?] / Inicio de nutrición enteral luego de una gastrostomía endoscópica, ¿es necesario esperar?

Traditionally, the initiation of enteral nutrition after a percutaneous endoscopic gastrostomy (PEG) is performed between 12 and 24 hours. Different research suggests that early initiation might be a safe option. Our aim was to determine whether starting enteral nutrition 4 hours after performing PEG is a safe practice in terms of risk of intolerance, complications, or death, compared to starting it at 12 hours. We carried out a prospective, randomized, multicenter study in third and fourth level institutions in Bogotá and Cundinamarca, between June 2020 and May 2022, 117 patients were included who were randomized into 2 groups, group A with early nutrition initiation (4 hours), and standard group B (12 hours). The most frequent mechanism of dysphagia was cerebrovascular disease (43%), followed by complications of COVID19 infection (26%). There were no statistically significant differences between the groups evaluated regarding the percentage of intolerance to nutrition, RR = 0.93 (CI 0.30-2.90), there were also no differences in terms of postoperative complications, (RR) = 0.34 (CI 0.09-1.16), and no differences were found in mortality between the evaluated groups, (RR) = 1.12 (CI 0.59-2.15). In conclusion, early initiation of nutrition through the gastrostomy, 4 hours after performing the PEG, is a safe behavior that is not related to greater intolerance to nutrition, complications, or death, compared to later initiation.

Anomaly Detection in Multi-Wavelength Photoplethysmography Using Lightweight Machine Learning Algorithms.

Over the past few years, there has been increased interest in photoplethysmography (PPG) technology, which has revealed that, in addition to heart rate and oxygen saturation, the pulse shape of the PPG signal contains much more valuable information. Lately, the wearable market has shifted towards a multi-wavelength and multichannel approach to increase signal robustness and facilitate the extraction of other intrinsic information from the signal. This transition presents several challenges related to complexity, accuracy, and reliability of algorithms. To address these challenges, anomaly detection stages can be employed to increase the accuracy and reliability of estimated parameters. Powerful algorithms, such as lightweight machine learning (ML) algorithms, can be used for anomaly detection in multi-wavelength PPG (MW-PPG). The main contributions of this paper are (a) proposing a set of features with high information gain for anomaly detection in MW-PPG signals in the classification context, (b) assessing the impact of window size and evaluating various lightweight ML models to achieve highly accurate anomaly detection, and (c) examining the effectiveness of MW-PPG signals in detecting artifacts.

Novel Multi-Parametric Sensor System for Comprehensive Multi-Wavelength Photoplethysmography Characterization.

Photoplethysmography (PPG) is widely used to assess cardiovascular health. However, its usage and standardization are limited by the impact of variable contact force and temperature, which influence the accuracy and reliability of the measurements. Although some studies have evaluated the impact of these phenomena on signal amplitude, there is still a lack of knowledge about how these perturbations can distort the signal morphology, especially for multi-wavelength PPG (MW-PPG) measurements. This work presents a modular multi-parametric sensor system that integrates continuous and real-time acquisition of MW-PPG, contact force, and temperature signals. The implemented design solution allows for a comprehensive characterization of the effects of the variations in these phenomena on the contour of the MW-PPG signal. Furthermore, a dynamic DC cancellation circuitry was implemented to improve measurement resolution and obtain high-quality raw multi-parametric data. The accuracy of the MW-PPG signal acquisition was assessed using a synthesized reference PPG optical signal. The performance of the contact force and temperature sensors was evaluated as well. To determine the overall quality of the multi-parametric measurement, an in vivo measurement on the index finger of a volunteer was performed. The results indicate a high precision and accuracy in the measurements, wherein the capacity of the system to obtain high-resolution and low-distortion MW-PPG signals is highlighted. These findings will contribute to developing new signal-processing approaches, advancing the accuracy and robustness of PPG-based systems, and bridging existing gaps in the literature.

Inicio de nutrición enteral luego de una gastrostomía endoscópica, ¿es necesario esperar?

Tradicionalmente, el inicio de nutrición enteral, luego de una gastrostomía endoscópica percutánea (GEP) se realiza entre 12 a 24 horas. Diferentes investigaciones sugieren que iniciarla más temprano podría ser una opción segura. El objetivo es determinar si el inicio de nutrición enteral a las 4 horas después de realizar GEP es una conducta segura en cuanto al riesgo de intolerancia, complicaciones o muerte, comparado con iniciarla a las 12 horas. Realizamos un estudio prospectivo, aleatorizado, multicéntrico en instituciones de tercer y cuarto nivel de Bogotá y Cundinamarca, entre junio de 2020 y mayo de 2022, se incluyeron 117 pacientes que fueron aleatorizados en 2 grupos, el grupo A de inicio temprano de nutrición (4 horas), y el grupo B de inicio estándar (12 horas). El mecanismo más frecuente de disfagia fue la enfermedad cerebrovascular (43%), seguido por complicaciones de infección por COVID-19 (26%). No hubo diferencias estadísticamente significativas entre los grupos evaluados respecto al porcentaje de intolerancia a la nutrición, RR = 0,93 (IC 0,30-2,90), tampoco hubo diferencias en términos de complicaciones posoperatorias, (RR) = 0,34 (IC 0,09-1,16), y no se encontraron diferencias en la mortalidad entre los grupos evaluados, (RR) = 1,12 (IC 0,59 - 2,15). En conclusión, el inicio de nutrición a través de la gastrostomía de forma temprana, 4 horas después de la realización de la GEP es una conducta segura que no se relaciona con una mayor intolerancia a la nutrición, complicaciones o muerte, en comparación con un inicio más tardío.

Traditionally, the initiation of enteral nutrition after a percutaneous endoscopic gastrostomy (PEG) is performed between 12 and 24 hours. Different research suggests that early initiation might be a safe option. Our aim was to determine whether starting enteral nutrition 4 hours after performing PEG is a safe practice in terms of risk of intolerance, complications, or death, compared to starting it at 12 hours. We carried out a prospective, randomized, multicenter study in third and fourth level institutions in Bogotá and Cundinamarca, between June 2020 and May 2022, 117 patients were included who were randomized into 2 groups, group A with early nutrition initiation (4 hours), and standard group B (12 hours). The most frequent mechanism of dysphagia was cerebrovascular disease (43%), followed by complications of COVID19 infection (26%). There were no statistically significant differences between the groups evaluated regarding the percentage of intolerance to nutrition, RR = 0.93 (CI 0.30-2.90), there were also no differences in terms of postoperative complications, (RR) = 0.34 (CI 0.09-1.16), and no differences were found in mortality between the evaluated groups, (RR) = 1.12 (CI 0.59-2.15). In conclusion, early initiation of nutrition through the gastrostomy, 4 hours after performing the PEG, is a safe behavior that is not related to greater intolerance to nutrition, complications, or death, compared to later initiation.

Insights into the origins of inverted circular dichroism in thin films of a chiral side chain polyfluorene.

We synthesized a fluorene-bithiophene co-polymer with chiral side chains (cPFT2) and investigated its chiroptical properties via synchotronradiation circular dichroism. We observed that thin films of the polymer display an intense circular dichroism (CD) upon annealing, which is of opposite handedness to the CD reported for similar polyfluorenes bearing the same enantiomeric chiral side chain. We then contrast the properties of this polymer with chiral side chain fluorene homopolymer (cPF) and observe large differences in their thin film morphology. Using photoluminescence spectroscopy, we uncover evidence of polymer chain bending in cPFT2, which is further supported by theoretical calculations, and propose an explanation for the observed inverted optical activity.

Intercity Mobility Assessment Facing the Demographic Challenge: A Survey-Based Research.

The key factor in moving towards a more sustainable travel model is based on improving mobility, especially in rural areas that share territorial dynamics with urban areas and are connected by a daily flow of inhabitants. The purpose of this article is to carry out a diagnosis of the daily mobility patterns of the inhabitants of a number of rural municipalities, with the aim of promoting sustainability and mitigating the phenomenon of territorial depopulation in future local planning policies. The research methodology is based on the use of revealed preference surveys together with accessibility analysis using GIS tools, allowing for an in-depth knowledge of the mobility patterns of the municipalities in the area under analysis. In this respect, the reference parameters in terms of territorial accessibility are determined by applying the network analysis procedure to basic public services. The results reflect the existence of an unbalanced modal split with a preponderance of private vehicle use (regardless of the destination or the reason for the journey). In addition, a very weak inter-municipal connection dynamic is observed. There is a knowledge gap in the verification of the long-term suitability of sustainable measures in rural areas implemented after the development of mobility plans (in order to assess their effectiveness).

Malignant hypercalcemia at a national referral center. A retrospective analysis

Malignant hypercalcemia is the most frequent endocrinological emergency in cancer. The factors related to its occurrence have not been evaluated, nor are there any related studies in Colombia. Objective: to determine the factors associated with the onset of malignant hypercalcemia (MH) in patients hospitalized at Instituto Nacional de Cancerología (2014-2019). Design: a retrospective analytical case-control study Population: 230 cases of adults with cancer and calcium corrected for albumin equal to or greater than 10.5 mg/dL and 223 controls of cancer patients with normal corrected calcium (8.5 to 10.4 mg/ dL) were included. Squamous cell carcinoma was used as the pairing variable. Analysis: univariate and bivariate analyses between the variables and the occurrence of MH were conducted to determine association, and raw ORs were calculated. Depending on their statis tical significance (p<0.05), they were included in the logistic regression for multivariate analysis and to rule out bias. Results: the median calcium for cases: 12.98 mg/dL (11.64-14.42) vs. 9.4 mg/dL (9.02-9.74) (p < 0.0001). The two groups were similar in age and sex. There was more metastasis in the cases (60.0% vs. 39.91%) (p< 0.0001). Altogether, 54.34% of the cases developed neurological symp toms. The median hospital stay was 16 days (IQR 9-27) vs. 9 days (IQR 6-17) for the controls (p< 0.0001), and inpatient deaths occurred in 48.70% vs. 16.59% (p < 0.0001). The following showed an association with MH: normal albumin, OR 0.41 (95% CI 0.29-0.55); a Karnofsky Index greater than or equal to 70, OR 0.98 (95% CI 0.97-0.99); and metastasis, OR 1.87 (95% CI 1.23-2.84). (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2555).

La hipercalcemia maligna es la urgencia endocrinológica en cáncer más frecuente, los factores relacionados a su presentación no han sido evaluados, ni hay estudios relacionados en Colombia. Objetivo: determinar los factores asociados a la presentación de hipercalcemia maligna (HM), en pacientes hospitalizados en el Instituto Nacional de Cancerología (2014-2019). Diseño: estudio analítico retrospectivo de casos y controles. Población: se incluyeron 230 casos de adultos con cáncer y calcio corregido por albúmina mayor e igual a 10.5 mg/dL y 223 controles de pacientes oncológicos con calcio corregido normal (8.5 a 10.4 mg/dL), se usó el carcinoma escamocelular como variable pareadora. Análisis: para establecer asociación se realizó el análisis univariado y bivariado entre las variables y la presentación de HM, se calcularon OR crudos, según significancia estadística (p<0.05) fueron incluidas en regresión logística para el análisis multivariado y excluir sesgos. Resultados: mediana de calcio en los casos: 12.98 mg/dL (11.64-14.42) vs. 9.4 mg/dL (9.02-9.74) (p < 0.0001). Los dos grupos presentaron edad y sexo similares. Hubo mayor proporción de metástasis en los casos (60.0% vs. 39.91%) (p < 0.0001). El 54.34% de los casos desarrolló síntomas neuro lógicos. La mediana de estancia hospitalaria fue de 16 días (RIC 9-27) vs. nueve días (RIC 6-17) para los controles (p < 0.0001) y la muerte intrahospitalaria se presentó en el 48.70% vs. 16.59% (p < 0.0001). Demostraron asociación con HM: albúmina normal OR 0.41 (IC 95% 0.29-0.55), índice de Karnofsky mayor o igual 70 OR 0.98 (IC95% 0.97-0.99) y presencia de metástasis OR 1.87 (IC 95% 1.23-2.84). (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2555).

A Collective Intelligence Platform to Support Older Cancer Survivors: Towards the Definition of LifeChamps System and Big Data Reference Architecture.

Within the most recent years, most of the cancer patients are older age, which implies the necessity to a better understanding of aging and cancer connection. This work presents the LifeChamps solution built on top of cutting-edge Big Data architecture and HPC infrastructure concepts. An innovative architecture was envisioned supported by the Big Data Value Reference Model and answering the system requirements from high to low level and from logical to physical perspective, following the "4+1 architectural model".

Bulk Heterojunction Organic Semiconductor Photoanodes: Tuning Energy Levels to Optimize Electron Injection.

The use of a bulk heterojunction of organic semiconductors to drive photoelectrochemical water splitting is an emerging trend; however, the optimum energy levels of the donor and acceptor have not been established for photoanode operation with respect to electrolyte pH. Herein, we prepare a set of donor polymers and non-fullerene acceptors with varying energy levels to probe the effect of photogenerated electron injection into a SnO2-based substrate under sacrificial photo-oxidation conditions. Photocurrent density (for sacrificial oxidation) up to 4.1 mA cm-2 was observed at 1.23 V vs reversible hydrogen electrode in optimized photoanodes. Moreover, we establish that a lower-lying donor polymer leads to improved performance due to both improved exciton separation and better charge collection. Similarly, lower-lying acceptors also give photoanodes with higher photocurrent density but with a later photocurrent onset potential and a narrower range of pH for good operation due to the Nernstian behavior of the SnO2, which leads to a smaller driving force for electron injection at high pH.

PPG EduKit: An Adjustable Photoplethysmography Evaluation System for Educational Activities.

The grown interest in healthcare applications has made biomedical engineering one of the fastest growing disciplines in recent years. Photoplethysmography (PPG) has gained popularity in recent years due to its versatility for noninvasive monitoring of vital signs such as heart rate, respiratory rate, blood oxygen saturation and blood pressure. In this work, an adjustable PPG-based educational device called PPG EduKit, which aims to facilitate the learning of the PPG technology for a wide range of engineering and medical disciplines is proposed. Through the use of this educational platform, the PPG signal can be understood, modified and implemented along with the extraction of its relevant physiological information from a didactic, intuitive and practical way. The PPG Edukit is evaluated for the extraction of physiological parameters such as heart rate and blood oxygen level, demonstrating how its features contribute to engineering and medical students to assimilate technical concepts in electrical circuits, biomedical instrumentation, and human physiology.

Critical role of H-aggregation for high-efficiency photoinduced charge generation in pristine pentamethine cyanine salts.

The mechanism of photoinduced symmetry-breaking charge separation in solid cyanine salts at the base of organic photovoltaic and optoelectronic devices is still debated. Here, we employ femtosecond transient absorption spectroscopy (TAS) to monitor the charge transfer processes occurring in thin films of pristine pentamethine cyanine (Cy5). Oxidized dye species are observed in Cy5-hexafluorophosphate salts upon photoexcitation, resulting from electron transfer from monomer excited states to H-aggregates. The charge separation proceeds with a quantum yield of 86%, providing the first direct proof of high efficiency intrinsic charge generation in organic salt semiconductors. The impact of the size of weakly coordinating anions on charge separation and transport is studied using TAS alongside electroabsorption spectroscopy and time-of-flight techniques. The degree of H-aggregation decreases with increasing anion size, resulting in reduced charge transfer. However, there is little change in carrier mobility, as despite the interchromophore distance increasing, the decrease in energetic disorder helps to alleviate the trapping of charges by H-aggregates.

Early cardiovascular sympathetic reflex activation is independent of occlusion time during reactive hyperemia / La activación temprana del reflejo simpático cardiovascular es independiente del tiempo de oclusión durante la hiperemia reactiva / A ativação precoce do reflexo simpático cardiovascular é independente do tempo de oclusão durante a hiperemia reativa

Purpose: The aim of the present study was to investigate the role of occlusion time in dynamic changes of autonomic activation during reactive hyperemia. Methods: Healthy subjects (n = 30) in the age range of 18­25 years participated in this study. Vascular reactivity was assessed by measuring the dynamic changes in finger pulse volume amplitude (PVA) and  pulse transit time relative to the RR intervals in the test (occluded arm) and control arm (contralateral non-occluded arm) during 1, 3 and 5 minute of occlusion using two separate Photoplethysmographic sensors. Heart Rate Variability was computed from a simultaneously acquired ECG signal to monitor the dynamic changes in cardiac autonomic nervous activity. Time-varying analysis of all signals were shown every 1 second in average response graphs. Results: Time-varying analysis of vascular and autonomic response during reactive hyperemia demonstrated the presence of a characteristic response pattern with an increase in the Sympathetic index and a decrease in Parasympathetic index at 8 to 10 seconds, an increase in heart rate at 20 seconds and a progressive increase in PVA during the first 60 seconds after occlusion regardless of the time spent in the procedure. Moreover, a decrease in pulse transits time relative to RR intervals,  followed by an increase regardless of the occlusion time was evidenced.  Conclusions: Early cardiovascular sympathetic activation is independent of occlusion time during reactive hyperemia, which suggests this is a vascular autonomic reflex response involved in the generation of the physiological phenomenon of reactive hyperemia.

Objetivo: El objetivo del presente estudio fue investigar el papel del tiempo de oclusión en los cambios dinámicos de la activación autónoma durante la hiperemia reactiva.Métodos: Participaron en este estudio sujetos sanos (n = 30) en el rango de edad de 18 a 25 años. La reactividad vascular se evaluó midiendo los cambios dinámicos en la amplitud del volumen del pulso del dedo (PVA) y el tiempo de tránsito del pulso en relación con los intervalos RR en la prueba (brazo ocluido) y el brazo de control (brazo contralateral no ocluido) durante 1, 3 y 5 minutos. de oclusión utilizando dos sensores fotopletismográficos separados. La variabilidad de la frecuencia cardíaca se calculó a partir de una señal de ECG adquirida simultáneamente para controlar los cambios dinámicos en la actividad nerviosa autónoma cardíaca. El análisis variable en el tiempo de todas las señales se mostró cada segundo en gráficos de respuesta promedio.Resultados: El análisis variable en el tiempo de la respuesta vascular y autonómica durante la hiperemia reactiva demostró la presencia de un patrón de respuesta característico con un aumento en el índice simpático y una disminución en el índice parasimpático a los 8 a 10 segundos, un aumento en la frecuencia cardíaca a los 20 segundos y un aumento progresivo de PVA durante los primeros 60 segundos después de la oclusión independientemente del tiempo transcurrido en el procedimiento. Además, se evidenció una disminución en el tiempo de tránsitos del pulso en relación con los intervalos RR, seguido de un aumento independientemente del tiempo de oclusión.Conclusiones: La activación simpática cardiovascular temprana es independiente del tiempo de oclusión durante la hiperemia reactiva, lo que sugiere que se trata de una respuesta refleja autonómica vascular involucrada en la generación del fenómeno fisiológico de hiperemia reactiva.

Objetivo: O objetivo do presente estudo foi investigar o papel do tempo de oclusão nas mudanças dinâmicas da ativação autonômica durante a hiperemia reativa.Métodos: Participaram deste estudo indivíduos saudáveis ​​(n = 30) na faixa etária de 18 a 25 anos. A reatividade vascular foi avaliada medindo as mudanças dinâmicas na amplitude do volume do pulso do dedo (PVA) e tempo de trânsito do pulso em relação aos intervalos RR no teste (braço ocluído) e braço controle (braço não ocluído contralateral) durante 1, 3 e 5 minutos de oclusão usando dois sensores fotopletismográficos separados. A variabilidade da frequência cardíaca foi calculada a partir de um sinal de ECG adquirido simultaneamente para monitorar as mudanças dinâmicas na atividade nervosa autonômica cardíaca. A análise variável no tempo de todos os sinais foi mostrada a cada 1 segundo em gráficos de resposta média.Resultados: A análise variável no tempo da resposta vascular e autonômica durante a hiperemia reativa demonstrou a presença de um padrão de resposta característico com um aumento no índice simpático e uma diminuição no índice parassimpático em 8 a 10 segundos, um aumento na frequência cardíaca em 20 segundos e aumento progressivo do PVA durante os primeiros 60 segundos após a oclusão, independentemente do tempo despendido no procedimento. Além disso, foi evidenciada uma diminuição no tempo de trânsito de pulso em relação aos intervalos RR, seguida de um aumento independente do tempo de oclusão.Conclusões: A ativação simpática cardiovascular precoce independe do tempo de oclusão durante a hiperemia reativa, o que sugere que se trata de uma resposta reflexa autonômica vascular envolvida na geração do fenômeno fisiológico de hiperemia reativa.

Matrix-Bound Nanovesicles: The Effects of Isolation Method upon Yield, Purity, and Function.

Identification of matrix-bound nanovesicles (MBV) as ubiquitous components of the extracellular matrix (ECM) raises questions regarding their biologic functions and their potential theranostic application. Unlike liquid-phase extracellular vesicles (e.g., exosomes), MBV are tightly bound to the ECM, which makes their isolation and harvesting more challenging. The indiscriminate use of different methods to harvest MBV can alter or disrupt their structural and/or functional integrity. The objective of the present study was to compare the effect of various MBV harvesting methods upon yield, purity, and biologic activity. Combinations of four methods to solubilize the ECM (collagenase [COL], liberase [LIB], or proteinase K [PK] and nonenzymatic elution with potassium chloride) and four isolation methods (ultracentrifugation, ultrafiltration [UF], density barrier, and size exclusion chromatography [SEC]) were used to isolate MBV from urinary bladder-derived ECM. All combinations of solubilization and isolation methods allowed for the harvesting of MBV, however, distinct differences were noted. The highest yield, purity, cellular uptake, and biologic activity were seen with MBV isolated by a combination of liberase or collagenase followed by SEC. The combination of proteinase K and UF was shown to have detrimental effects on bioactivity. The results show the importance of selecting appropriate MBV harvesting methods for the characterization and evaluation of MBV and for analysis of their potential theranostic application. Impact statement Identification of matrix-bound nanovesicles (MBV) as ubiquitous components of the extracellular matrix (ECM) has raised questions regarding their biologic functions and their potential theranostic application. This study demonstrates that the harvesting methods used can result in samples with physical and biochemical properties that are unique to the isolation and solubilization methods used. Consequently, developing harvesting methods that minimize sample contamination with ECM remnants and/or solubilization agents will be essential in determining the theranostic potential of MBV in future studies.

Esophageal extracellular matrix hydrogel mitigates metaplastic change in a dog model of Barrett's esophagus.

Chronic inflammatory gastric reflux alters the esophageal microenvironment and induces metaplastic transformation of the epithelium, a precancerous condition termed Barrett's esophagus (BE). The microenvironmental niche, which includes the extracellular matrix (ECM), substantially influences cell phenotype. ECM harvested from normal porcine esophageal mucosa (eECM) was formulated as a mucoadhesive hydrogel, and shown to largely retain basement membrane and matrix-cell adhesion proteins. Dogs with BE were treated orally with eECM hydrogel and omeprazole (n = 6) or omeprazole alone (n = 2) for 30 days. eECM treatment resolved esophagitis, reverted metaplasia to a normal, squamous epithelium in four of six animals, and downregulated the pro-inflammatory tumor necrosis factor-α+ cell infiltrate compared to control animals. The metaplastic tissue in control animals (n = 2) did not regress. The results suggest that in vivo alteration of the microenvironment with a site-appropriate, mucoadhesive ECM hydrogel can mitigate the inflammatory and metaplastic response in a dog model of BE.

Influence of the Infill Orientation on the Properties of Zirconia Parts Produced by Fused Filament Fabrication.

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.