Super-resolution Left Ventricular Flow and Pressure Mapping by Navier-Stokes-Informed Neural Networks.

Intraventricular vector flow mapping (VFM) is a growingly adopted echocardiographic modality that derives time-resolved two-dimensional flow maps in the left ventricle (LV) from color-Doppler sequences. Current VFM models rely on kinematic constraints arising from planar flow incompressibility. However, these models are not informed by crucial information about flow physics; most notably the pressure and shear forces within the fluid and the resulting accelerations. This limitation has rendered VFM unable to combine information from different time frames in an acquisition sequence or derive fluctuating pressure maps. In this study, we leveraged recent advances in artificial intelligence (AI) to develop AI-VFM, a vector flow mapping modality that uses physics-informed neural networks (PINNs) encoding mass conservation and momentum balance inside the LV, and no-slip boundary conditions at the LV endocardium. AI-VFM recovers the flow and pressure fields in the LV from standard echocardiographic scans. It performs phase unwrapping and recovers flow data in areas without input color-Doppler data. AI-VFM also recovers complete flow maps at time points without color-Doppler input data, producing super-resolution flow maps. We show that informing the PINNs with momentum balance is essential to achieving temporal super-resolution and significantly increases the accuracy of AI-VFM compared to informing the PINNs only with mass conservation. AI-VFM is solely informed by each patient's flow physics; it does not utilize explicit smoothness constraints or incorporate data from other patients or flow models. AI-VFM takes 15 minutes to run in off-the-shelf graphics processing units and its underlying PINN framework could be extended to map other flow-associated metrics like blood residence time or the concentration of coagulation species.

Reduced-order models of wall shear stress patterns in the left atrial appendage from a data-augmented atrial database.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting over 1% of the population. It is usually triggered by irregular electrical impulses that cause the atria to contract irregularly and ineffectively. It increases blood stasis and the risk of thrombus formation within the left atrial appendage (LAA) and aggravates adverse atrial remodeling. Despite recent efforts, LAA flow patterns representative of AF conditions and their association with LAA stasis remain poorly characterized. AIM: To develop reduced-order data-driven models of LAA flow patterns during atrial remodeling in order to uncover flow disturbances concurrent with LAA stasis that could add granularity to clinical decision criteria. METHODS: We combined a geometric data augmentation process with projection of results from 180 CFD atrial simulations on a universal LAA coordinate (ULAAC) system. The projection approach enhances data visualization and facilitates direct comparison between different anatomical and functional states. ULAAC projections were used as input for a proper orthogonal decomposition (POD) algorithm to build reduced-order models of hemodynamic metrics, extracting flow characteristics associated with AF and non-AF anatomies. RESULTS: We verified that the ULAAC system provides an adequate representation to visualize data distributions on the LAA surface and to build POD-based reduced-order models. These models revealed significant differences in LAA flow patterns for atrial geometries that underwent adverse atrial remodeling and experienced elevated blood stasis. Together with anatomical morphing-based patient-specific data augmentation, this approach could facilitate data-driven analyses to identify flow features associated with thrombosis risk due to atrial remodeling.

Efficient multi-fidelity computation of blood coagulation under flow.

Clot formation is a crucial process that prevents bleeding, but can lead to severe disorders when imbalanced. This process is regulated by the coagulation cascade, a biochemical network that controls the enzyme thrombin, which converts soluble fibrinogen into the fibrin fibers that constitute clots. Coagulation cascade models are typically complex and involve dozens of partial differential equations (PDEs) representing various chemical species' transport, reaction kinetics, and diffusion. Solving these PDE systems computationally is challenging, due to their large size and multi-scale nature. We propose a multi-fidelity strategy to increase the efficiency of coagulation cascade simulations. Leveraging the slower dynamics of molecular diffusion, we transform the governing PDEs into ordinary differential equations (ODEs) representing the evolution of species concentrations versus blood residence time. We then Taylor-expand the ODE solution around the zero-diffusivity limit to obtain spatiotemporal maps of species concentrations in terms of the statistical moments of residence time, [Formula: see text], and provide the governing PDEs for [Formula: see text]. This strategy replaces a high-fidelity system of N PDEs representing the coagulation cascade of N chemical species by N ODEs and p PDEs governing the residence time statistical moments. The multi-fidelity order (p) allows balancing accuracy and computational cost providing a speedup of over N/p compared to high-fidelity models. Moreover, this cost becomes independent of the number of chemical species in the large computational meshes typical of the arterial and cardiac chamber simulations. Using a coagulation network with N = 9 and an idealized aneurysm geometry with a pulsatile flow as a benchmark, we demonstrate favorable accuracy for low-order models of p = 1 and p = 2. The thrombin concentration in these models departs from the high-fidelity solution by under 20% (p = 1) and 2% (p = 2) after 20 cardiac cycles. These multi-fidelity models could enable new coagulation analyses in complex flow scenarios and extensive reaction networks. Furthermore, it could be generalized to advance our understanding of other reacting systems affected by flow.

Bioética e integración de la inteligencia artificial en la medicina: reflexiones desde el cine sobre la condición humana y la responsabilidad hacia las generaciones futuras / Bioethics and Integration of AI in Medicine: reflections from Cinema about the Human Condition and Responsibility towards Future Generations

La discusión sobre la ética en torno a la inteligencia artificial y la medicina ha ganado cada vez más relevancia en el ámbito académico y público. Independientemente de los diversos enfoques, hay un hecho innegable: la práctica médica y todos los agentes involucrados, tanto profesionales como usuarios, se verán condicionados por la inteligencia artificial. En este análisis ético narrativo, basado en el cine, se aborda la condición humana y la responsabilidad hacia las generaciones futuras como elementos cruciales dentro de la discusión bioética y fundamentales para lograr una incorporación reflexiva y coherente de la inteligencia artificial en la medicina. Como conclusión, se propone que la autenticidad, la responsabilidad y el diálogo son pilares esenciales en el proceso de integración de esta tecnología

The discussion on the ethics surrounding artificial intelligence and medicine has gained increasing relevance in the academic and public sphere. Regardless of the various approaches, there is an undeniable fact: medical practice and all the agents involved, both professionals and users, will be conditioned by artificial intelligence. In this narrative ethical analysis, based on cinema, the human condition and responsibility towards future generations are addressed as crucial elements within the bioethical discussion and fundamental to achieve a thoughtful and coherent incorporation of artificial intelligence in medicine. In conclusion, it is proposed that authenticity, responsibility and dialogue are essential pillars in the process of integration of this technology

Enhanced degradation of ciprofloxacin in water using ternary photocatalysts TiO2/SnO2/g-C3N4 under UV, visible, and solar light.

In this study, we report on the synthesis of ternary photocatalysts comprising TiO2/SnO2/g-C3N4 for the degradation of ciprofloxacin (CIP) in water. SnO2 nanoparticles were synthesized via the sol-gel method, while g-C3N4 was obtained through melamine calcination. Commercial TiO2 and SnO2 nanopowders were also used. The heterojunctions were synthesized via the wet impregnation method. The photocatalysts were characterized via various techniques, including XRD, TEM, STEM, FTIR, N2 adsorption, UV-Vis DR, and hole tests. Photocatalytic degradation tests of CIP were carried out under UV, visible, and solar radiation. The P25/npA/g-C3N4 (90/10) material exhibited the best performance, achieving CIP degradation of over 97%. The synthesized materials demonstrated excellent initial adsorption of CIP, around 30%, which facilitated subsequent degradation. Notably, the CIP photocatalytic degradation tests performed under solar radiation showed a synergistic effect between the base materials and carbon nitride in highly energetic environments. These results highlight the effectiveness of ternary photocatalysts TiO2/SnO2/g-C3N4 for CIP degradation, particularly under solar radiation.

Efficient multi-fidelity computation of blood coagulation under flow.

Clot formation is a crucial process that prevents bleeding, but can lead to severe disorders when imbalanced. This process is regulated by the coagulation cascade, a biochemical network that controls the enzyme thrombin, which converts soluble fibrinogen into the fibrin fibers that constitute clots. Coagulation cascade models are typically complex and involve dozens of partial differential equations (PDEs) representing various chemical species' transport, reaction kinetics, and diffusion. Solving these PDE systems computationally is challenging, due to their large size and multi-scale nature. We propose a multi-fidelity strategy to increase the efficiency of coagulation cascade simulations. Leveraging the slower dynamics of molecular diffusion, we transform the governing PDEs into ordinary differential equations (ODEs) representing the evolution of species concentrations versus blood residence time. We then Taylor-expand the ODE solution around the zero-diffusivity limit to obtain spatiotemporal maps of species concentrations in terms of the statistical moments of residence time, , and provide the governing PDEs for . This strategy replaces a high-fidelity system of N PDEs representing the coagulation cascade of N chemical species by N ODEs and p PDEs governing the residence time statistical moments. The multi-fidelity order( p ) allows balancing accuracy and computational cost, providing a speedup of over N/p compared to high-fidelity models. Using a simplified coagulation network and an idealized aneurysm geometry with a pulsatile flow as a benchmark, we demonstrate favorable accuracy for low-order models of p = 1 and p = 2. These models depart from the high-fidelity solution by under 16% ( p = 1) and 5% ( p = 2) after 20 cardiac cycles. The favorable accuracy and low computational cost of multi-fidelity models could enable unprecedented coagulation analyses in complex flow scenarios and extensive reaction networks. Furthermore, it can be generalized to advance our understanding of other systems biology networks affected by blood flow.

Embedded Fiber Bragg Grating Sensors for Monitoring Temperature and Thermo-Elastic Deformations in a Carbon Fiber Optical Bench.

A composite optical bench made up of Carbon Fiber Reinforced Polymer (CFRP) skin and aluminum honeycomb has been developed for the Tunable Magnetograph instrument (TuMag) for the SUNRISE III mission within the NASA Long Duration Balloon Program. This optical bench has been designed to meet lightweight and low sensitivity to thermal gradient requirements, resulting in a low Coefficient of Thermal Expansion (CTE). In addition to the flight model, a breadboard model identical to the flight one has been manufactured, including embedded fiber Bragg temperature and strain sensors. The aim of this is to explore if the use of distributed fiber Bragg gratings (FBGs) can provide valuable information for strain and temperature mapping of an optical instrument on board a space mission during its operation as well as its on-ground testing. Furthermore, surface-mounted strain FBG sensors and thermocouples have been installed in the optical bench for intercomparison purposes. This paper presents the results obtained from a thermal vacuum test consisting of three thermal cycles with stabilization steps at 100 °C, 60 °C, 20 °C and -20 °C. Experimental results provide information about how FBG embedded temperature sensors can provide a proper and quick response to the temperature changes of the optical bench and that embedded FBG strain sensors are able to measure micro-deformation induced in a close-to-zero CTE optical bench.

Pulmonary vein flow split effects in patient-specific simulations of left atrial flow.

Disruptions to left atrial (LA) blood flow, such as those caused by atrial fibrillation (AF), can lead to thrombosis in the left atrial appendage (LAA) and an increased risk of systemic embolism. LA hemodynamics are influenced by various factors, including LA anatomy and function, and pulmonary vein (PV) inflow conditions. In particular, the PV flow split can vary significantly among and within patients depending on multiple factors. In this study, we investigated how changes in PV flow split affect LA flow transport, focusing for the first time on blood stasis in the LAA, using a high-fidelity patient-specific computational fluid dynamics (CFD) model. We use an Immersed Boundary Method, simulating the flow in a fixed, uniform Cartesian mesh and imposing the movement of the LA walls with a moving Lagrangian mesh generated from 4D Computerized Tomography images. We analyzed LA anatomies from eight patients with varying atrial function, including three with AF and either a LAA thrombus or a history of Transient Ischemic Attacks (TIAs). Using four different flow splits (60/40% and 55/45% through right and left PVs, even flow rate, and same velocity through each PV), we found that flow patterns are sensitive to PV flow split variations, particularly in planes parallel to the mitral valve. Changes in PV flow split also had a significant impact on blood stasis and could contribute to increased risk for thrombosis inside the LAA, particularly in patients with AF and previous LAA thrombus or a history of TIAs. Our study highlights the importance of considering patient-specific PV flow split variations when assessing LA hemodynamics and identifying patients at increased risk for thrombosis and stroke. This knowledge is relevant to planning clinical procedures such as AF ablation or the implementation of LAA occluders.

Radiation and Dust Sensor for Mars Environmental Dynamic Analyzer Onboard M2020 Rover.

The Radiation and Dust Sensor is one of six sensors of the Mars Environmental Dynamics Analyzer onboard the Perseverance rover from the Mars 2020 NASA mission. Its primary goal is to characterize the airbone dust in the Mars atmosphere, inferring its concentration, shape and optical properties. Thanks to its geometry, the sensor will be capable of studying dust-lifting processes with a high temporal resolution and high spatial coverage. Thanks to its multiwavelength design, it will characterize the solar spectrum from Mars' surface. The present work describes the sensor design from the scientific and technical requirements, the qualification processes to demonstrate its endurance on Mars' surface, the calibration activities to demonstrate its performance, and its validation campaign in a representative Mars analog. As a result of this process, we obtained a very compact sensor, fully digital, with a mass below 1 kg and exceptional power consumption and data budget features.

Non-Newtonian blood rheology impacts left atrial stasis in patient-specific simulations.

The lack of mechanically effective contraction of the left atrium (LA) during atrial fibrillation (AF) disturbs blood flow, increasing the risk of thrombosis and ischemic stroke. Thrombosis is most likely in the left atrial appendage (LAA), a small narrow sac where blood is prone to stagnate. Slow flow promotes the formation of erythrocyte aggregates in the LAA, also known as rouleaux, causing viscosity gradients that are usually disregarded in patient-specific simulations. To evaluate these non-Newtonian effects, we built atrial models derived from 4D computed tomography scans of patients and carried out computational fluid dynamics simulations using the Carreau-Yasuda constitutive relation. We examined six patients, three of whom had AF and LAA thrombosis or a history of transient ischemic attacks (TIAs). We modeled the effects of hematocrit and rouleaux formation kinetics by varying the parameterization of the Carreau-Yasuda relation and modulating non-Newtonian viscosity changes based on residence time. Comparing non-Newtonian and Newtonian simulations indicates that slow flow in the LAA increases blood viscosity, altering secondary swirling flows and intensifying blood stasis. While some of these effects are subtle when examined using instantaneous metrics like shear rate or kinetic energy, they are manifested in the blood residence time, which accumulates over multiple heartbeats. Our data also reveal that LAA blood stasis worsens when hematocrit increases, offering a potential new mechanism for the clinically reported correlation between hematocrit and stroke incidence. In summary, we submit that hematocrit-dependent non-Newtonian blood rheology should be considered when calculating patient-specific blood stasis indices by computational fluid dynamics.

Characteristics, clinical outcomes, and risk factors of SARS-COV-2 infection in adult acute myeloid leukemia patients: experience of the PETHEMA group.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces higher morbidity and mortality in hematological malignancies, but evidence in acute myeloid leukemia (AML) is scarce. A multicenter observational study was conducted to determine the clinical outcomes and assess the impact of therapeutic approaches in adult AML patients with SARS-CoV-2 infection in the first wave (March-May 2020). Overall, 108 patients were included: 51.9% with active leukemia and 70.4% under therapeutic schedules for AML. Signs and symptoms of SARS-CoV-2 were present in 96.3% of patients and 82.4% received specific treatment for SARS-CoV-2. The mortality rate was 43.5% and was correlated with age, gender, active leukemia, dyspnea, severe SARS-CoV-2, intensive care measures, neutrophil count, and D-dimer levels. A protective effect was found with azithromycin, lopinavir/ritonavir, and normal liver enzyme levels. During the SARS-CoV-2 first wave, our findings suggested an increased mortality in AML in a short period. SARS-CoV-2 management could be guided by risk factors in AML patients.

Demonstration of Patient-Specific Simulations to Assess Left Atrial Appendage Thrombogenesis Risk.

Atrial fibrillation (AF) alters left atrial (LA) hemodynamics, which can lead to thrombosis in the left atrial appendage (LAA), systemic embolism and stroke. A personalized risk-stratification of AF patients for stroke would permit improved balancing of preventive anticoagulation therapies against bleeding risk. We investigated how LA anatomy and function impact LA and LAA hemodynamics, and explored whether patient-specific analysis by computational fluid dynamics (CFD) can predict the risk of LAA thrombosis. We analyzed 4D-CT acquisitions of LA wall motion with an in-house immersed-boundary CFD solver. We considered six patients with diverse atrial function, three with either a LAA thrombus (removed digitally before running the simulations) or a history of transient ischemic attacks (LAAT/TIA-pos), and three without a LAA thrombus or TIA (LAAT/TIA-neg). We found that blood inside the left atrial appendage of LAAT/TIA-pos patients had marked alterations in residence time and kinetic energy when compared with LAAT/TIA-neg patients. In addition, we showed how the LA conduit, reservoir and booster functions distinctly affect LA and LAA hemodynamics. Finally, fixed-wall and moving-wall simulations produced different LA hemodynamics and residence time predictions for each patient. Consequently, fixed-wall simulations risk-stratified our small cohort for LAA thrombosis worse than moving-wall simulations, particularly patients with intermediate LAA residence time. Overall, these results suggest that both wall kinetics and LAA morphology contribute to LAA blood stasis and thrombosis.

Síndrome de Cushing exógeno de difícil diagnóstico / Exogenous Cushings syndrome with a difficult diagnosis

Resumen Introducción: el síndrome de Cushing (SC) es un grupo de signos y síntomas causados por la exposición crónica al exceso de glucocorticoides. El uso de fármacos con glucocorticoides es la causa más frecuente, pero algunos productos vendidos como suplementos nutricionales o medicamentos naturistas para el control de los dolores articulares pueden contenerlos de forma oculta, lo cual dificulta el enfoque diagnóstico Presentación del caso: paciente de 40 años con signos clínico típicos de síndrome de Cushing con resultados discordantes en las pruebas diagnósticas para identificar su origen. Finalmente se logra establecer que el paciente consumía de forma crónica un producto "naturista" conocido como artrin®, el cual fue analizado en el laboratorio de la institución con resultados positivos para cortisol. Conclusión: la exposición crónica a glucocorticoides exógenos, ya sea subrepticia, desconocida o prescrita, causa SC y debe distinguirse tempranamente de las formas endógenas para evitar la realización de pruebas diagnósticas y tratamientos inadecuados.(Acta Med Colomb 2020; 45. DOI:https://doi.org/10.36104/amc.2020.1500).

Abstract Introduction: Cushing's syndrome (CS) is a group of signs and symptoms caused by chronic exposure to excessive glucocorticoids. The use of medications containing glucocorticoids is the most common cause, but they may be hidden in some products sold as nutritional supplements or naturopathic medications, which makes the diagnostic approach more difficult. Case presentation: this was a 40-year-old patient with typical clinical signs of Cushing's syndrome and discordant results of diagnostic tests to identify its origin. It was ultimately determined that the patient had been chronically taking a "naturopathic" product known as artrin®, which was analyzed in the institution's lab and found to contain cortisol. Conclusion: chronic exposure to exogenous glucocorticoids, whether surreptitious, unknown or prescribed, causes CS and should be promptly distinguished from endogenous forms to avoid inappropriate diagnostic tests and treatments.(Acta Med Colomb 2020; 45. DOI:https://doi.org/10.36104/amc.2020.1500).

Characterization of cyclitic membranes by ultrabiomicroscopy in patients with pars planitis.

BACKGROUND: In previous studies, authors use ultrasound biomicroscopy (UBM) to analyze the characteristics of cyclitic membranes and the associated complications in patients with pars planitis. However, there are no reports regarding the prevalence of cyclitic membranes or complications at diagnosis and during follow-up. PURPOSE: To describe the characteristics and complications of cyclitic membranes, as determined by UBM in patients with pars planitis using AVISO-S™ (Quantel Medical) equipment with a 50-MHz linear probe with a focus at the pars plana. DESIGN: This retrospective study reviewed UBM images of patients diagnosed with pars planitis, from the Inflammatory Eye Disease Clinic in Mexico City from January 2010 to June 2016. RESULTS: Cyclitic membranes were observed in the first UBM image in 67 eyes (56.7%) and during follow-up in 81 eyes (68.62%). In 67 eyes (82.71%), the cyclitic membranes extended through one or two quadrants. Extension toward the posterior lens capsule was recognized in 15 eyes (18.52%) and extension toward the peripheral retina in 12 eyes (14.81%). Complications included ciliary body detachments in 10 eyes (12.35%) and peripheral retinal traction in 8 eyes (9.88%). CONCLUSIONS: UBM is a valuable tool for the diagnosis of cyclitic membranes at admittance and during follow-up of patients with pars planitis; it helps the clinician to detect this complication early.

Fractura supracondílea de húmero y extremidad sin pulso. Uso de oximetría de pulso como predictor de lesión vascular en un caso pediátrico / Pulseless limb and supracondylar humeral fracture; use of pulse oximetry as a predictor of vascular injury in a pediatric case

Las fracturas supracondíleas del húmero (FSCH) representan la segunda lesión más frecuente en la infancia. La clasificación de Gartland, de acuerdo con la dirección y magnitud del desplazamiento orienta hacia su tratamiento. Las fracturas grado I solo requieren inmovilización y los grados del II al IV necesitan reducción generalmente cerrada, y fijación con agujas de Kirschner percutáneas. En los grados III y IV las lesiones neuro-vasculares se pueden presentar debido a las relaciones anatómicas de la fractura. La lesión vascular se debe sospechar y tener siempre en cuenta, debido a las secuelas que se pueden presentar de no tomar una conducta adecuada a tiempo. Actualmente existe controversia acerca de cuándo realizar la exploración quirúrgica ante una extremidad bien perfundida, sin pulso radial como resultado de una FSCH. Varios autores han reportado la utilidad de la onda de pulso en la oximetría como predictor de lesión vascular. En este artículo se presenta un caso clínico de FSCH con extremidad sin pulso y lesión de la arteria braquial, su manejo y evolución final.

Supracondylar fractures of the humerus are the second most frequent lesion of infancy. Gartland's classification uses the direction and magnitude of the displacement to determine its treatment. Grade I fractures need only immobilization and grades II to IV need reduction, generally closed, and percutaneous fixation with Kirschner needles. Neurovascular lesions may be present in grades III and IV because of the anatomic relations to the fracture. Vascular injury must always be suspected and taken into consideration because of the sequelae that may occur if not given adequate treatment promptly.There is currently controversy over when to do a surgical exploration in a well-perfused limb with absent radial pulse resulting from a supracondylar humeral fracture. Several authors have reported the usefulness of the waveformof the pulse oximeter in predicting vascular injury. In this article we present a clinical case of supracondylar humeral fracturewithpulseless limb and brachial artery injury, its management, and the outcome.

Análise morfológica da base do crânio, maxila e mandíbula em maloclusões classe I, II, III esqueléticas. Estudo em CBCT. / Morphologica analysis of the base of the skull Jaw and mandibula in maloclusions class I, II, III skeletals. Study in CBCT

Introdução: O objetivo desse estudo foi avaliar quantitativamente a anatomia 3D da Base do Crânio em pacientes com padrão esquelético Classe I, II e III. Material e Método: Um estudo retrospetivo, foi realizado com as imagens de TCFC de 75 pacientes. A amostra foi dividida em três grupos de acordo com o padrão esquelético de cada individuo: Classe I, II e III. As Imagens de TCFC foram reorientadas e foi realizada a segmentação dos arquivos. Foram posicionados pontos de referência em Base do Crânio, Maxila e Mandíbula. Posteriormente, foram construídos modelos volumétricos 3D da Base do Crânio, Maxila e Mandibula. Foram realizadas medidas angulares e lineares utilizando os pontos de referência. As medidas foram utilizadas para avaliar a morfologia da base do crânio e as suas correlações em diferentes padrões esqueléticos. Analise Estatística: As diferenças entre os grupos foram testadas usando o teste de ANOVA, e as correlações foram medidas utilizando o teste de correlação de Pearson. Resultados: Ainda sem muitas diferenças estatisticamente significativas entre os grupos, foram observadas algumas diferenças menores, onde a Classe II e III se comportam como extremos e a Classe I se comporta como intermediário. Foram observadas diferenças estatisticamente significativas para a posição 3D da Fossa Mandibular (p <0.05) e o Comprimento Mandibular (p <0.05). Foram verificadas correlações entre comprimento Mandibular, comprimento Maxilar e o posicionamento mandibular com uma serie de estruturas na Base do Crânio. Conclusões: Nossos resultados sugerem que o comprimento mandibular e o posicionamento da fossa mandibular podem estar relacionados com o padrão esquelético do individuo. (AU)

Introduction: The aim of this study was to quantitatively assess 3D anatomy of CB in patients with Class I, II and II skeletal patterns. Material and Methods: This retrospective study sample was composed by CBCT scans of 75 patients. The sample was divided into three groups according to the skeletal pattern: Class I, II and III. The CBCT scans were re-oriented and segmentation was performed. Landmarks were positioned in CB, Mx and Md. 3D models of CB, Mx, and Md were constructed, and linear and angular measurements was performed. Measurements were used to evaluate the CB morphology and correlations on different skeletal patterns. Statistical Analysis: The differences among groups were tested by ANOVA test and correlation was performed by Pearson correlation test. Results: Even without many significant differences between groups, were observed some differences between groups in most of the measure, where Class II and III have a greater distance between them and Class I behaves as an intermediary. Statistically significant differences were observed for 3D position of MF (p 0.05) and mandibular length (p 0.05). Correlation between MD length, Mx and Md positioning with some structures was verified. Conclusions: Our results suggested that de Md length and MF positioning can be related with de patient skeletal pattern. (AU)

Fundamentos fácticos y jurídicos para regular el servicio público de transporte en el área rural - Achacachi

Describe un escenario donde existe un monopolio de transporte que es controlado por un grupo de tranasportistas y así como también prestan un servicio deficiente