Sleep is required to consolidate odor memory and remodel olfactory synapses.

Animals with complex nervous systems demand sleep for memory consolidation and synaptic remodeling. Here, we show that, although the Caenorhabditis elegans nervous system has a limited number of neurons, sleep is necessary for both processes. In addition, it is unclear if, in any system, sleep collaborates with experience to alter synapses between specific neurons and whether this ultimately affects behavior. C. elegans neurons have defined connections and well-described contributions to behavior. We show that spaced odor-training and post-training sleep induce long-term memory. Memory consolidation, but not acquisition, requires a pair of interneurons, the AIYs, which play a role in odor-seeking behavior. In worms that consolidate memory, both sleep and odor conditioning are required to diminish inhibitory synaptic connections between the AWC chemosensory neurons and the AIYs. Thus, we demonstrate in a living organism that sleep is required for events immediately after training that drive memory consolidation and alter synaptic structures.

Understanding the Chemical Bond in Semiconductor/MXene Composites: TiO2 Clusters Anchored on the Ti2C MXene Surface.

First-principles calculations on titania clusters (TiO2)n (n=5 and 10) supported on the pristine Ti2C (0001) surface were carried out to understand the properties of semiconductor/MXene composites with implications in (photo)-catalysis. The reported results reveal a high exothermic interaction accompanied by a substantial charge transfer with a concomitant, notorious, deformation of the titania nanoclusters. The analysis of the density of states analysis of the composite systems evidences a metallic character with titania related states crossing the Fermi level. The picture of the chemical bonds is completed by the analysis of X-Ray Photoelectron Spectra (XPS) features, evidencing clear shifts of the C(1s) and O(1s) related peaks relative to the isolated systems that have a quite complex origin. This detailed analysis provides insights to experimentalists interested in the design and synthesis of these systems with possible applications in catalysis.

Purification and characterisation of the platelet-activating GPVI/FcRγ complex in SMALPs.

The collagen/fibrin(ogen) receptor, glycoprotein VI (GPVI), is a platelet activating receptor and a promising anti-thrombotic drug target. However, while agonist-induced GPVI clustering on platelet membranes has been shown to be essential for its activation, it is unknown if GPVI dimerisation represents a unique conformation for ligand binding. Current GPVI structures all contain only the two immunoglobulin superfamily (IgSF) domains in the GPVI extracellular region, so lacking the mucin-like stalk, transmembrane, cytoplasmic tail of GPVI and its associated Fc receptor γ (FcRγ) homodimer signalling chain, and provide contradictory insights into the mechanisms of GPVI dimerisation. Here, we utilised styrene maleic-acid lipid particles (SMALPs) to extract GPVI in complex with its two associated FcRγ chains from transfected HEK-293T cells, together with the adjacent lipid bilayer, then purified and characterised the GPVI/FcRγ-containing SMALPs, to enable structural insights into the full-length GPVI/FcRγ complex. Using size exclusion chromatography followed by a native polyacrylamide gel electrophoresis (PAGE) method, SMA-PAGE, we revealed multiple sizes of the purified GPVI/FcRγ SMALPs, suggesting the potential existence of GPVI oligomers. Importantly, GPVI/FcRγ SMALPs were functional as they could bind collagen. Mono-dispersed GPVI/FcRγ SMALPs could be observed under negative stain electron microscopy. These results pave the way for the future investigation of GPVI stoichiometry and structure, while also validating SMALPs as a promising tool for the investigation of human membrane protein interactions, stoichiometry and structure.

Biomechanical outcomes of pharmacological therapies for post-traumatic arthrofibrosis in preclinical animal models: a systematic review and meta-analysis.

PURPOSE/AIM OF THE STUDY: There is still no evidence of which drug has the greatest therapeutic potential for post-traumatic arthrofibrosis. The aim of this study is to systematically review the literature for quality evidence and perform a meta-analysis about the pharmacological therapies of post-traumatic arthrofibrosis in preclinical models. MATERIALS AND METHODS: A comprehensive and systematic search strategy was performed in three databases (MEDLINE, EMBASE and Web of Science) retrieving studies on the effectiveness of pharmacological therapies in the management of post-traumatic arthrofibrosis using preclinical models in terms of biomechanical outcomes. Risk of bias assessment was performed using the SYRCLE's risk of bias tool. A meta-analysis using a random-effects model was conducted if a minimum of three studies reported homogeneous outcomes for drugs with the same action mechanism. RESULTS: Forty-six studies were included in the systematic review and evaluated for risk of bias. Drugs from 6 different action mechanisms of 21 studies were included in the meta-analysis. Overall, the methodological quality of the studies was poor. Statistically significant overall effect in favor of reducing contracture was present for anti-histamines (Chi2 p = 0.75, I2 = 0%; SMD (Standardized Mean Difference) = -1.30, 95%CI: -1.64 to -0.95, p < 0.00001) and NSAIDs (Chi2 p = 0.01, I2 = 63%; SMD= -0.93, 95%CI: -1.58 to -0.28, p = 0.005). CONCLUSIONS: Anti-histamines, particularly ketotifen, have the strongest evidence of efficacy for prevention of post-traumatic arthrofibrosis. Some studies suggest a potential role for NSAIDs, particularly celecoxib, although heterogeneity among the included studies is significant.

First principles modeling of composites involving TiO2 clusters supported on M2C MXenes.

First-principles calculations based on density functional theory are performed to investigate the formation of titania/MXene composites taking (TiO2)5/M2C (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W) as cases of study. The present systematic analysis confirms a favorable, high exothermic interaction, which promotes important structural reconstructions of the (TiO2)5 cluster along with charge transfer from the MXene to titania. MXenes composed of d3 transition metals promote the strongest interaction, deformation energy, and charge transfer, followed by d4 and d5 M2C MXenes. We provide evidence that the formation of these (TiO2)5/M2C composites is governed by charge transfer, leading to scaling relationships. By using the electronegativity of the metal composing MXene and the MXene d-band center, we also establish linear correlations that can be used to predict the interaction strength of (TiO2)5/M2C composites just from the knowledge of the MXene composition. It is likely that the present trends hold for other TiO2/MXene composites.

Correction: The nature of the electronic ground state of M2C (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) MXenes.

Correction for 'The nature of the electronic ground state of M2C (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) MXenes' by Néstor García-Romeral et al., Phys. Chem. Chem. Phys., 2023, 25, 31153-31164, https://doi.org/10.1039/D3CP04402E.

Perineural Infiltration: A Comprehensive Review of Diagnostic, Prognostic, and Therapeutic Implications.

ABSTRACT: Perineural infiltration refers to a neoplastic cell involvement in, around, and through the nerves. It is considered as one of the neoplastic dissemination pathways. Thus, its identification is crucial to establish the prognosis of some malignant skin neoplasms, such as squamous cell carcinoma, and explains the locally aggressive behavior of cutaneous neoplasms, such as microcystic adnexal carcinoma. We have conducted a review of malignant and benign skin tumors in which perineural infiltration has been described, and we also discuss some histopathological findings that may simulate perineural infiltration.

Design and Implementation of an AI-Enabled Sensor for the Prediction of the Behaviour of Software Applications in Industrial Scenarios.

In the era of Industry 4.0 and 5.0, a transformative wave of softwarisation has surged. This shift towards software-centric frameworks has been a cornerstone and has highlighted the need to comprehend software applications. This research introduces a novel agent-based architecture designed to sense and predict software application metrics in industrial scenarios using AI techniques. It comprises interconnected agents that aim to enhance operational insights and decision-making processes. The forecaster component uses a random forest regressor to predict known and aggregated metrics. Further analysis demonstrates overall robust predictive capabilities. Visual representations and an error analysis underscore the forecasting accuracy and limitations. This work establishes a foundational understanding and predictive architecture for software behaviours, charting a course for future advancements in decision-making components within evolving industrial landscapes.

Data-Monitoring Solution for Desalination Processes: Cooling Tower and Mechanical Vapor Compression Hybrid System.

The advancement of novel water treatment technologies requires the implementation of both accurate data measurement and recording processes. These procedures are essential for acquiring results and conducting thorough analyses to enhance operational efficiency. In addition, accurate sensor data facilitate precise control over chemical treatment dosages, ensuring optimal water quality and corrosion inhibition while minimizing chemical usage and associated costs. Under this framework, this paper describes the sensoring and monitoring solution for a hybrid system based on a cooling tower (CT) connected to mechanical vapor compression (MVC) equipment for desalination and brine concentration purposes. Sensors connected to the data commercial logger solution, Almemo 2890-9, are also discussed in detail such as temperature, relative humidity, pressure, flow rate, etc. The monitoring system allows remote control of the MVC based on a server, GateManager, and TightVNC. In this way, the proposed solution provides remote access to the hybrid system, being able to visualize gathered data in real time. A case study located in Cartagena (Spain) is used to assess the proposed solution. Collected data from temperature transmitters, pneumatic valves, level sensors, and power demand are included and discussed in the paper. These variables allow a subsequent forecasting process to estimate brine concentration values. Different sample times are included in this paper to minimize the collected data from the hybrid system within suitable operation conditions. This solution is suitable to be applied to other desalination processes and locations.

Efficacy of a Telemonitoring System as a Complementary Strategy in the Treatment of Patients With Heart Failure: Randomized Clinical Trial.

Episodes of decompensation are the main cause of hospital admissions in patients with heart failure. For this reason, the use of mobile apps emerges as an excellent strategy to improve coverage, real-time monitoring, and timeliness of care. ControlVit is an electronic application for early detection of complications studied within the context of a tertiary university hospital. Patients were randomized to the use of ControlVit versus placebo, during a 6-month follow-up. The primary outcome was the difference in numbers of readmissions and deaths for heart failure between both groups. One hundred forty patients were included (intervention = 71, placebo = 69), with an average age of 66 years old; 71% were men. The main etiology of heart failure was ischemic (60%), whereas the main comorbidities were arterial hypertension (44%), dyslipidemia (42%), hypothyroidism (38%), chronic kidney disease (38%), and diabetes mellitus (27%). The primary outcome occurred more frequently in the control group: readmission due to decompensation for heart failure (control group n = 14 vs intervention group n = 3; P = .0081), and death (control group n = 11 vs intervention group n = 3; P = .024). In heart failure patients, ControlVit is a useful and supplementary tool, which reduces hospital admissions due to episodes of decompensation.

Dysphagia secondary to neuroendocrine carcinoma: a rare esophageal tumor.

We present two clinical cases, a 68-year-old male and a 55-year-old female, who are being studied for progressive solid food dysphagia. The initial gastroscopy revealed a polypoid lesion in the first case and a partially stenosing lesion in the second case. Both lesions were located in the mid-esophagus and presented a normal mucosa. Histological diagnosis confirmed an esophageal neuroendocrine carcinoma (NEC) of large cell and small cell types, respectively.

Extraosseous Ewing's sarcoma of the pancreas.

We present the clinical case of a 21-year-old male with abdominal pain in the left hypochondrium radiating to the ipsilateral lumbar area and a weight loss of 2kg over a month, secondary to a large palpable intra-abdominal mass in the examination. TAC revealed a large solid mass with necrotic-cystic component which depended of the pancreas, infiltrated the spleen, enveloped the celiac trunk and affected to the splenic vases. Inmunohistochemical and molecular study confirmed the diagnosis extraosseus Ewing sarcoma (EES).

Infrared thermography for normal endothelial function screening.

BACKGROUND: Endothelial dysfunction (ED) suspicion will allow to prevent accelerated atherosclerosis and premature death. OBJECTIVE: To establish the usefulness of thermography for endothelial function screening in adults with cardiovascular risk factors. MATERIAL AND METHODS: Cross-sectional, analytical diagnostic test. A brachial arterial diameter (BAD) increase < 11% at one-minute post-ischemia meant probable ED and was confirmed if BAD was ≥ 11% post-sublingual nitroglycerin. Thermographic photographs of the palmar region were obtained at one minute. Descriptive statistics, ROC curve, Mann-Whitney's U-test, chi-square test, or Fisher's exact test were used. RESULTS: Thirty-eight subjects with a median age of 50 years, and with 624 thermographic measurements were included. Nine had ED (flow-mediated vasodilation [FMV]: 2.5%). The best cutoff point for normal endothelial function in subjects with cardiovascular risk factors was ≥ 36 °C at one minute of ischemia, with 85% sensitivity, 70% specificity, positive and negative predictive values of 78 and 77%, area under the curve of 0.796, LR+ 2.82, LR- 0.22. CONCLUSION: An infrared thermography-measured temperature in the palmar region greater than or equal to 36 °C after one minute of ischemia is practical, non-invasive, and inexpensive for normal endothelial function screening in adults with cardiovascular risk factors.

ANTECEDENTES: La sospecha de disfunción endotelial (DE) permitirá prevenir la aterosclerosis acelerada y la muerte prematura. OBJETIVO: Establecer la utilidad de la termografía en el cribado de la función endotelial en adultos con factores de riesgo cardiovascular. MATERIAL Y MÉTODOS: Estudio transversal analítico de prueba diagnóstica. El incremento del diámetro de la arteria braquial < 11 % a un minuto posisquemia significó probable DE, confirmada si el diámetro fue ≥ 11 % posnitroglicerina sublingual. Se obtuvieron fotografías termográficas al minuto de la región palmar. Se aplicó estadística descriptiva, curva ROC, pruebas U de Mann-Whitney, chi cuadrada o exacta de Fisher. RESULTADOS: Se incluyeron 38 sujetos, mediana de edad de 50 años, con 624 mediciones termográficas; nueve presentaron DE (vasodilatación mediada por flujo de 2.5 %). El mejor punto de corte para la función endotelial normal en sujetos con factores de riesgo cardiovascular fue ≥ 36 °C al minuto de isquemia, con sensibilidad de 85%, especificidad de 70%, valores predictivos positivo y negativo de 78 y 77%, área bajo la curva de 0.796, razón de verisimilitud positiva de 2.82 y razón de verisimilitud negativa de 0.22. CONCLUSIÓN: La medición de la temperatura en la región palmar mediante termografía infrarroja ≥ 36 °C tras un minuto de isquemia es práctica, no invasiva y económica para el cribado de la función endotelial normal en adultos con factores de riesgo cardiovascular.

Noninvasive detection of microsatellite instability in patients with endometrial cancer.

The analysis of mismatch repair proteins in solid tissue is the standard of care (SoC) for the microsatellite instability (MSI) characterization in endometrial cancer (EC). Uterine aspirates (UAs) or circulating-DNA (cfDNA) samples capture the intratumor heterogeneity and provide a more comprehensive and dynamic molecular diagnosis. Thus, MSI analysis by droplet-digital PCR (ddPCR) in UAs and cfDNA can provide a reliable tool to characterize and follow-up the disease. The UAs, paraffin-embedded tumor tissue (FFPE) and longitudinal plasma samples from a cohort of 90 EC patients were analyzed using ddPCR panel and compared to the SoC. A high concordance (96.67%) was obtained between the analysis of MSI markers in UAs and the SoC. Three discordant cases were validated as unstable by ddPCR on FFPE samples. Besides, a good overall concordance (70.27%) was obtained when comparing the performance of the ddPCR assay on UAs and cfDNA in high-risk tumors. Importantly, our results also evidenced the value of MSI analysis to monitor the disease evolution. MSI evaluation in minimally invasive samples shows great accuracy and sensitivity and provides a valuable tool for the molecular characterization and follow-up of endometrial tumors, opening new opportunities for personalized management of EC.

Villoglandular Pattern in HPV-associated Endocervical Adenocarcinoma is Associated With Excellent Prognosis: A Reappraisal of 31 Cases Using IECC and Silva Pattern Classification.

Villoglandular adenocarcinoma of the cervix is a rare histologic entity that typically develops in young women, characterized by an association with oral contraceptives and excellent prognosis, though this point is controversial. These tumors have not been studied in the context of the International Endocervical Adenocarcinoma Criteria and Classification (IECC) or Silva Pattern Classification. We analyzed 31 cases that met strict diagnostic criteria, including being completely excised with negative margins. These were categorized according to IECC and Silva Pattern Classification and the association with various pathologic parameters analyzed. Most patients were young with a mean age of 41.1 (range 25-79). There were 14 (45.2%) pattern A, 11 (35.5%) pattern B, and 6 (19.3%) pattern C cases. Only 1 of 22 patients (4.5%) presented with lymph node metastasis at the time of diagnosis (pattern C, stage IB1) and 3 (9.7%) had lymphovascular invasion (2 pattern C, 1 pattern B). Overall survival was 100%, while recurrence-free survival was 96.2% for the entire cohort with only 1 case (3.2%) recurring 25 mo after surgery (IB2, pattern B). Kaplan Meier analysis (log rank test) revealed no significant correlation for recurrence-free survival at 5 and 10 yr associated with depth of invasion, tumor size, Silva pattern, FIGO stage, lymphovascular invasion, or lymph node metastasis. Cox univariate analysis demonstrated no independent prognostic factors predicting recurrence-free survival. These results indicate that completely excised villoglandular adenocarcinoma generally has an excellent prognosis and when Silva Pattern Classification is applied, those tumors that potentially have a higher chance for adverse outcomes can be identified.

Characterizing the Folding Transition-State Ensembles in the Energy Landscape of an RNA Tetraloop.

Molecular dynamics (MD) simulations have become increasingly powerful and can now describe the folding/unfolding of small biomolecules in atomic detail. However, a major challenge in MD simulations is to represent the complex energy landscape of biomolecules using a small number of reaction coordinates. In this study, we investigate the folding pathways of an RNA tetraloop, gcGCAAgc, using five classical MD simulations with a combined simulation time of approximately 120 µs. Our approach involves analyzing the tetraloop dynamics, including the folding transition state ensembles, using the energy landscape visualization method (ELViM). The ELViM is an approach that uses internal distances to compare any two conformations, allowing for a detailed description of the folding process without requiring root mean square alignment of structures. This method has previously been applied to describe the energy landscape of disordered ß-amyloid peptides and other proteins. The ELViM results in a non-linear projection of the multidimensional space, providing a comprehensive representation of the tetraloop's energy landscape. Our results reveal four distinct transition-state regions and establish the paths that lead to the folded tetraloop structure. This detailed analysis of the tetraloop's folding process has important implications for understanding RNA folding, and the ELViM approach can be used to study other biomolecules.

Theoretical study of electrocatalytic properties of low-dimensional freestanding PbTiO3 for hydrogen evolution reactions.

The discovery of novel materials for catalytic purposes that are highly stable is one of the main challenges nowadays for reducing our dependence on fossil fuels. Here, low-dimensional PbTiO3 is introduced as an electrocatalyst using first-principles calculations. Density-functional theory calculations indicate that 2D-PbTiO3 is dynamically and thermodynamically stable. Our results show that a single oxygen defect vacancy in 2D-PbTiO3 can play a key role in enhancing the hydrogen evolution reaction (HER), together with the Ti atoms. Our study concludes that the Volmer-Heyrovsky mechanism is a more favorable route to achieve HER than the Volmer-Tafel mechanism, including solvation and vacuum conditions.

The nature of the electronic ground state of M2C (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) MXenes.

A systematic computational study is presented aimed at accurately describing the electronic ground state nature and properties of M2C (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) MXenes. Electronic band structure calculations in the framework of density functional theory (DFT), carried out with different types of basis sets and employing the generalized gradient approach (GGA) and hybrid functionals, provide strong evidence that Ti2C, Zr2C, Hf2C, and Cr2C MXenes exhibit an open-shell conducting ground state with localized spins on the metal atoms, while V2C, Nb2C, Mo2C, Ta2C, and W2C MXenes exhibit a diamagnetic conducting ground state. For Ti2C, Zr2C, Hf2C, and Cr2C, the analysis of the low-lying spin polarized solutions with different spin orderings indicates that their ground states are antiferromagnetic (AFM), consisting of two ferromagnetic (FM) metal layers coupled antiferromagnetically. For the diamagnetic MXenes, the converged spin polarized solutions are significantly less stable than the closed shell solution except for the case of V2C and Mo2C where those excited open shell solutions can be thermally accessible (less than 300 meV per formula unit). The analysis of charge and spin density distributions of the ground state of the MXenes reveals that, in all cases, the metal atoms have a net charge close to +1 e and C atoms close to -2 e. In the case of diamagnetic MXenes, the electronic structure of V2C, Nb2C, and Ta2C is consistent with metal atoms exhibiting a closed-shell s2d2 configuration whereas for Mo2C, and W2C is consistent with a low-spin s1d4 configuration although the FM solution is close in energy for V2C and Mo2C suggesting that they may play a role in their chemistry at high temperature. For the open shell MXenes, the spin density primarily located at the metal atoms showing one unpaired electron per Ti+, Zr+, and Hf+ magnetic center, consistent with s2d1 configuration of the metal atom, and of ∼3.5 unpaired electrons per Cr+ magnetic center interpreted as a mixture of s2d3 and high-spin s1d4 configuration. Finally, the analysis of the density of states reveals the metallic character of all these bare MXenes, irrespective of the nature of the ground state, with significant covalent contributions for Mo2C and W2C.

How does thickness affect magnetic coupling in Ti-based MXenes.

The magnetic nature of Ti2C, Ti3C2, and Ti4C3 MXenes is determined from periodic calculations within density functional theory and using the generalized gradient approximation based PBE functional, the PBE0 and HSE06 hybrids, and the on-site Hubbard corrected PBE+U one, in all cases using a very tight numerical setup. The results show that all functionals consistently predict a magnetic ground state for all MXenes, with spin densities mainly located at the Ti surface atoms. The analysis of solutions corresponding to different spin orderings consistently show that all functionals predict an antiferromagnetic conducting ground state with the two ferromagnetic outer (surface) Ti layers being antiferromagnetically coupled. A physically meaningful spin model is proposed, consistent with the analysis of the chemical bond, with closed shell, diamagnetic, Ti2+ like ions in inner layers and surface paramagnetic Ti+ like centers with one unpaired electron per magnetic center. From a Heisenberg spin model, the relevant isotropic magnetic coupling constants are extracted from an appropriate mapping of total energy differences per formula unit to the expected energy values of the spin Hamiltonian. While the numerical values of the magnetic coupling constants largely depend on the used functional, the nearest neighbor intralayer coupling is found to be always ferromagnetic, and constitutes the dominant interaction, although two other non-negligible interlayer antiferromagnetic terms are involved, implying that the spin description cannot be reduced to NN interaction only. The influence of the MXene thickness is noticeable for the dominant ferromagnetic interaction, increasing its value with the MXene width. However, the interlayer interactions are essentially due to the covalency effects observed in all metallic solutions which, as expected, decay with distance. Within the PBE+U approach, a U value of 5 eV is found to closely simulate the results from hybrid functionals for Ti2C and less accurately for Ti3C2 and Ti4C3.

[Comparative analysis of the accreditation of medical facilities in Canada, Chile, the Autonomous Community of Andalusia, Denmark, and MexicoAnálise comparativa da acreditação de estabelecimentos de saúde no Canadá, Chile, Comunidade Autônoma da Andaluzia, Dinamarca e México]. / Análisis comparativo de la acreditación de unidades médicas en Canadá, Chile, la Comunidad Autónoma de Andalucía, Dinamarca y México.

Objective: To compare and contrast the characteristics of the accreditation process for health care facilities in Canada, Chile, the Autonomous Community of Andalusia (Spain), Denmark, and Mexico, in order to identify shared characteristics, differences, and lessons learned that may be useful for other countries and regions. Methods: An observational, analytical, retrospective study using open-access secondary sources on the accreditation and certification of health care facilities in 2019-2021 in these countries and regions. The general characteristics of the accreditation processes are described and comments are made on key aspects of the design of these programs. Additionally, analytical categories were created for degree of implementation and level of complexity, and the positive and negative results reported are summarized. Results: The operational components of the accreditation processes are country-specific, although they share similarities. The Canadian program is the only one that involves some form of responsive evaluation. There is a wide range in the percentage of establishments accredited from country to country (from 1% in Mexico to 34.7% in Denmark). Notable lessons learned include the complexity of application in a mixed public-private system (Chile), the risk of excessive bureaucratization (Denmark), and the need for clear incentives (Mexico). Conclusions: The accreditation programs operate in a unique way in each country and region, achieve varying degrees of implementation, and have an assortment of problems, from which lessons can be learned. Elements that hinder their implementation should be considered and adjustments made for the health systems of each country and region.

Objetivo: Comparar as características do processo de acreditação de estabelecimentos de saúde no Canadá, Chile, Comunidade Autônoma da Andaluzia, Dinamarca e México, a fim de identificar elementos comuns e diferenças, bem como lições aprendidas que podem ser úteis para outros países e regiões. Métodos: Estudo observacional, analítico e retrospectivo usando fontes secundárias de livre acesso sobre acreditação e certificação de estabelecimentos de saúde durante o período 2019-2021 nos países e regiões supracitados. As características gerais do processo de acreditação e suas respostas a pontos-chave no delineamento de tais programas foram descritas. Além disso, foram geradas categorias de análise para o andamento de sua implantação e seu grau de complexidade, e os desfechos favoráveis e desfavoráveis relatados foram resumidos. Resultados: Os componentes operacionais do processo de acreditação são peculiares a cada país, embora compartilhem certas semelhanças. O programa canadense é o único que contempla algum tipo de avaliação responsiva. Houve grande variação entre países no percentual de estabelecimentos acreditados (de 1% no México a 34,7% na Dinamarca). Entre as lições aprendidas, destacam-se a complexidade da aplicação do sistema misto público-privado (Chile), o risco de burocratização excessiva (Dinamarca) e a necessidade de incentivos claros (México). Conclusões: Os programas de acreditação operam de forma peculiar em cada país ou região, têm diferentes escopos e também apresentam diversos problemas a partir dos quais podemos aprender. É preciso considerar os elementos que dificultam a implementação e realizar as adequações necessárias para os sistemas de saúde de cada país ou região.