Patient-specific multi-physics simulations of fibrotic changes in left atrial tissue mechanics impact on hemodynamics.

Stroke is a leading cause of death and disability worldwide. Atrial myopathy, including fibrosis, is associated with an increased risk of ischemic stroke, but the mechanisms underlying this association are poorly understood. Fibrosis modifies myocardial structure, impairing electrical propagation and tissue biomechanics, and creating stagnant flow regions where clots could form. Fibrosis can be mapped non-invasively using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, fibrosis maps are not currently incorporated into stroke risk calculations or computational electro-mechano-fluidic models. We present multi-physics simulations of left atrial (LA) myocardial motion and hemodynamics using patient-specific anatomies and fibrotic maps from LGE-MRI. We modify tissue stiffness and active tension generation in fibrotic regions and investigate how these changes affect LA flow for different fibrotic burdens. We find that fibrotic regions and, to a lesser extent, non-fibrotic regions experience reduced myocardial strain, resulting in decreased LA emptying fraction consistent with clinical observations. Both fibrotic tissue stiffening and hypocontractility independently reduce LA function, but together, these two alterations cause more pronounced effects than either one alone. Fibrosis significantly alters flow patterns throughout the atrial chamber, and particularly, the filling and emptying jets of the left atrial appendage (LAA). The effects of fibrosis in LA flow are largely captured by the concomitant changes in LA emptying fraction except inside the LAA, where a multi-factorial behavior is observed. This work illustrates how high-fidelity, multi-physics models can be used to study thrombogenesis mechanisms in a patient-specific manner, shedding light onto the link between atrial fibrosis and ischemic stroke. Key points: Left atrial (LA) fibrosis is associated with arrhythmogenesis and increased risk of ischemic stroke; its extent and pattern can be quantified on a patient-specific basis using late gadolinium enhancement magnetic resonance imaging.Current stroke risk prediction tools have limited personalization, and their accuracy could be improvedfib by incorporating patient-specific information like fibrotic maps and hemodynamic patterns.We present the first electro-mechano-fluidic multi-physics computational simulations of LA flow, including fibrosis and anatomies from medical imaging.Mechanical changes in fibrotic tissue impair global LA motion, decreasing LA and left atrial appendage (LAA) emptying fractions, especially in subjects with higher fibrosis burdens.Fibrotic-mediated LA motion impairment alters LA and LAA flow near the endocardium and the whole cavity, ultimately leading to more stagnant blood regions in the LAA.

Factors Influencing Engagement Across the Motivational PrEP Cascade Among Latino SMM: A Mixed-Methods Analysis from the Perspectives of Community Providers and Latino SMM.

Latino sexual minority men (SMM) are a highly vulnerable population to HIV, and while pre-exposure prophylaxis (PrEP) has emerged as a promising biomedical tool for HIV prevention among them, its utilization remains disproportionately low in this community despite its potential. Understanding the barriers along the PrEP continuum of care, known as the "PrEP cascade," is crucial for effectively implementing PrEP interventions. Therefore, the objective of our study was twofold: first, to explore the stage of Latino SMM in the PrEP cascade by examining disparities in demographics, social factors, and healthcare aspects; second, to gain insights from healthcare providers who have direct clinical experience with our population regarding the challenges faced by Latino SMM in accessing and adhering to PrEP. Based on the study findings, the majority of participants (n = 74; 49%) were in the contemplation stage, and only one in ten Latino SMM (10.6%) were currently adherent to PrEP. Compared to those who were at least second-generation, first-generation status had a positive association (B = 0.699, SE = 0.208, ß = 0.351, p < .001) with engagement along the PrEP Contemplation Ladder. Conversely, having at least one parent who did not have legal residency, relative to those whose parents were both U.S. citizens or held legal residency documentation, was found to have a negative association (B = - 0.689, SE = 0.245, ß = 0.245, p = .006) with engagement along the PrEP Contemplation Ladder. Additionally, discussing PrEP with a healthcare provider had a positive association (B = 0.374, SE = 0.179, ß = 0.185, p = .038) with engagement along the PrEP Contemplation Ladder. Qualitative results from our study suggest that some Latinos who initially agreed to start using PrEP ended up getting lost in the care pipeline and failed to attend their scheduled appointments. Providers also noted that many patients lacked access to a pharmacy where they felt comfortable obtaining their PrEP prescription, leading them to discontinue use after only a few months. These findings emphasize the importance of considering the unique needs, culture, and background of Latinos, including care delivery and provider attitudes that can facilitate progress through the PrEP cascade.

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.

Rural-Urban Differences in HIV Sexual Risk Behaviors and HIV Service Utilization Among Adolescent Sexual Minority Males in the United States.

In the United States, HIV prevalence is increasing in rural areas, specifically among rural adolescent sexual minority males (ASMM). However, it is unclear what HIV sexual risk behaviors rural ASMM engage in and what HIV preventative services they utilize. This study aimed to (1) document the lifetime HIV sexual risk behaviors and service utilization of rural ASMM and (2) compare rural-urban differences in the prevalence of HIV sexual risk behaviors and service utilization. We analyzed data collected from 1615 ASMM who participated in a baseline survey for an online HIV prevention program from April 2018 to June 2020. We compared the prevalence of lifetime HIV sexual risk behaviors and HIV healthcare utilization among rural and urban participants via descriptive statistics, chi-square tests, linear and logistic regressions, and zero-inflated Poisson regressions. These analyses indicated that rural ASMM were more likely than urban ASMM to engage in condomless sex when they had anal sex. Rural ASMM could benefit from offline and online evidence-based HIV prevention interventions, especially interventions that increase condom use.

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.

Disclosure, minority stress, and mental health among bisexual, pansexual, and queer (bi+) adults: The roles of primary sexual identity and multiple sexual identity label use.

Bisexual people are at increased risk for anxiety and depression compared to heterosexual and gay/lesbian people, but little is known about people who use other labels to describe attractions to more than one gender (e.g., pansexual, queer; collectively "bi+"). In addition, some people use more than one label to describe their sexual orientation, but research has yet to examine whether using one versus multiple labels is associated with identity-related experiences or mental health. To address these gaps, we explored potential differences in disclosure, minority stress, and mental health among bi+ adults based on primary sexual identity and multiple label use. As part of a larger project, 669 bi+ adults completed an online survey. Primary sexual identities included bisexual (53.2%), pansexual (26.3%), and queer (20.5%), and 55.2% used multiple labels. Compared to bisexual participants, pansexual participants reported higher disclosure, discrimination from heterosexual people, and depression. Pansexual participants also reported higher anxiety and lower internalized binegativity, but these associations became non-significant after adjusting for demographics. Queer participants reported higher disclosure, discrimination from heterosexual people, and anxiety, but only the difference in disclosure remained significant in adjusting analyses. Finally, participants who used multiple labels reported higher disclosure and discrimination from heterosexual and gay/lesbian people, but only the difference in discrimination from gay/lesbian people remained significant in adjusted analyses. Findings highlight the heterogeneity of bi+ individuals and the importance of considering bisexual, pansexual, and queer individuals as unique groups as well as considering whether bi+ individuals use one or multiple sexual identity labels.

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.

Stakeholders' Perspectives About Cultural Strategies to Support PrEP for Latino Sexual Minority Men.

Compared with non-Latino White sexual minority men, Latino sexual minority men (LSMM) have lower engagement with HIV pre-exposure prophylaxis (PrEP) and likelihood of discussing PrEP with a health care provider. The overall goal of the current study was to collect data from community stakeholders to inform the integration of culturally relevant factors into an empirically supported PrEP prevention program. Between December 2020 and August 2021, 18 interviews were conducted with 18 stakeholders with experience delivering health and social services. Themes identified are: (1) stakeholders' perspectives of new HIV infections among LSMM; (2) stakeholders' perspectives of general cultural variables; and (3) the development of culturally tailored programs. Our findings demonstrate how culturally competent stakeholders can leverage their established rapport and trust to reduce the negative effects of machismo and/or homophobia in the Latinx community to promote HIV prevention.

Lysozyme crystallization in hydrogel media under ultrasound irradiation.

Sonocrystallization implies the application of ultrasound radiation to control the nucleation and crystal growth depending on the actuation time and intensity. Its application allows to induce nucleation at lower supersaturations than required under standard conditions. Although extended in inorganic and organic crystallization, it has been scarcely explored in protein crystallization. Now, that industrial protein crystallization is gaining momentum, the interest on new ways to control protein nucleation and crystal growth is advancing. In this work we present the development of a novel ultrasound bioreactor to study its influence on protein crystallization in agarose gel. Gel media minimize convention currents and sedimentation, favoring a more homogeneous and stable conditions to study the effect of an externally generated low energy ultrasonic irradiation on protein crystallization avoiding other undesired effects such as temperature increase, introduction of surfaces which induce nucleation, destructive cavitation phenomena, etc. In-depth statistical analysis of the results has shown that the impact of ultrasound in gel media on crystal size populations are statistically significant and reproducible.

Identifying leaks in the STEM recruitment pipeline among sexual and gender minority US secondary students.

PURPOSE: Research establishes the critical need to address the underrepresentation of women and racial/ethnic minorities in science, technology, engineering, and mathematics (STEM). While emergent research addresses similar challenges for sexual and gender minorities (SGM), this research remains scant and focuses on adult experiences. This analysis examines subgroup differences and the impact of bullying on STEM engagement outcomes among a national sample of SGM secondary students in the U.S. METHOD: This report provides descriptive and multivariable regression analysis of national survey data (n = 539) on the experiences of pre-college students who identify as SGM, including the effects of within-school anti-SGM bullying on STEM identity, perceptions of STEM climate, and STEM intentions. RESULTS: Roughly 50% of the sample intended to enter a STEM field (compared to 25% in previous general samples). Bullying in school was negatively associated with STEM identity and perceptions of STEM climate. Sense of belonging is positively associated with perceptions of STEM climate and STEM intentions. Being non-binary and being a transgender man were associated with decreased sense of belonging and negative perception of STEM climate. CONCLUSION: This report is the first to identify factors influencing STEM engagement among SGM secondary students and suggests that issues of STEM engagement are already present in adolescence. Moreover, the findings also establish the relationship between anti-SGM bullying and STEM outcomes highlighting the importance of this marginalization experience. Future research should further examine sub-group differences and the persistence of these effects. These findings highlight the need for research and intervention addressing STEM outcomes in SGM populations. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03511131.

Experimental Evidence of Generation and Reception by a Transluminal Axisymmetric Shear Wave Elastography Prototype.

Experimental evidence on testing a non-ultrasonic-based probe for a new approach in transluminal elastography was presented. The proposed modality generated shear waves by inducing oscillatory rotation on the lumen wall. Detection of the propagated waves was achieved at a set of receivers in mechanical contact with the lumen wall. The excitation element of the probe was an electromagnetic rotational actuator whilst the sensing element was comprised by a uniform anglewise arrangement of four piezoelectric receivers. The prototype was tested in two soft-tissue-mimicking phantoms that contained lumenlike conduits and stiffer inclusions. The shear wave speed of the different components of the phantoms was characterized using shear wave elastography. These values were used to estimate the time-of-flight of the expected reflections. Ultrafast ultrasound imaging, based on Loupas' algorithm, was used to estimate the displacement field in transversal planes to the lumenlike conduit and to compare against the readouts from the transluminal transmission-reception tests. Experimental observations between ultrafast imaging and the transluminal probe were in good agreement, and reflections due to the stiffer inclusions were detected by the transluminal probe. The obtained experimental evidence provided proof-of-concept for the transluminal elastography probe and encouraged further exploration of clinical applications.

[Multicentric inflammatory pseudotumor]. / Seudotumor inflamatorio multicéntrico.

Inflammatory pseudotumor is a non-neoplastic process characterized by irregular growth of inflammatory cells. This type of tumor can arise in any part of the body; most are confined to a single site and are benign. We present the case of a 51-year-old man in whom a solitary pulmonary nodule was detected as an incidental finding. Right pulmonary lobectomy was performed and histopathological analysis led to a diagnosis of inflammatory pseudotumor. The patient subsequently developed tumors in the contralateral lung and cervix, the latter being highly aggressive. We found no reports of this association in the literature, prompting the present case report.

Impact of supervision and self-assessment on doctor-patient communication in rural Mexico.

OBJECTIVE: To determine whether supervision and self-assessment activities can improve doctor-patient communication. SETTING AND PARTICIPANTS: Six supervisors, 60 doctors in their last year of training, and 232 primary health care patients at rural health clinics in Michoacan, Mexico. DESIGN: The main evaluation compared post-intervention measures in control and intervention groups. A small panel study also examined changes from baseline to post-intervention rounds in both groups. INTERVENTION: Over a 4-month period, specially trained supervisors added 1 hour of supervision on interpersonal communication and counseling (IPC/C) to regular site visits. Doctors, who had received prior IPC/C training, periodically audiotaped and assessed their own consultations. MAIN OUTCOME MEASURES: These comprised frequency of doctors' facilitative communication, doctors' biomedical information-giving, and patients' active communication. RESULTS: The performance of all doctors improved markedly over the study period, but gains in facilitative communication and information-giving were significantly greater in the intervention than the control group. No single component of the intervention was responsible for the improvement; it resulted from the combination of activities. The doctors appreciated the more supportive relationship with supervisors that resulted from the intervention and found listening to themselves on audiotape a powerful, although initially stressful, experience. CONCLUSION: Supportive supervision and self-assessment activities can reinforce IPC/C training, prompt reflection and learning, and help novice doctors improve their interpersonal communication skills.

Boletín estadístico epidemiológico: Año 1995 / Epidemiological Statistical Bulletin: Year 1995

La presente publicación describe el recojo y procesamiento de la información estadística de los profesionales y técnicos de los servicios asistenciales y administrativos de los establecimientos de salud, el cual refleja con más exactitud los problemas de salud y enfermedad que motivan la concurrencia de los asegurados a los servicios de atención médica del IPSS

Enfoque metodológico para la realización de un plan de trabajo en la esfera de la salud / Methodologic approach for the performance of a working plan in the health sphere

Se analizan los antecedentes existentes en el trabajo concernientes a la realización de planes en el Sistema Nacional de Salud, la necesidad del plan como un instrumento de planificación y control del trabajo y se ofrecen los criterios fundamentales para la confección, puesta en práctica y control del mismo, basados en la experiencia acumulada en el proceso de coordinación de esta actividad