A dataset exploring urban comfort through novel wearables and environmental surveys.

This study presents a comprehensive dataset capturing indoor environmental parameters, physiological responses, and subjective perceptions across three global cities. Utilizing wearable sensors, including smart eyeglasses, and a modified Cozie app, environmental and physiological data were collected, along with pre-screening, onboarding, and recurring surveys. Peripheral cues facilitated participant engagement with micro-EMA surveys, minimizing disruption over a 5-day collection period.

Proxy methods for detection of inhalation exposure in simulated office environments.

Background: Modern health concerns related to air pollutant exposure in buildings have been exacerbated owing to several factors. Methods for assessing inhalation exposures indoors have been restricted to stationary air pollution measurements, typically assuming steady-state conditions.

Objective: We aimed to examine the feasibility of several proxy methods for estimating inhalation exposure to CO, PM, and PM in simulated office environments.

A Tri-Leaflet Nitinol Mesh Scaffold for Engineering Heart Valves.

The epidemiology of valvular heart disease has significantly changed in the past few decades with aging as one of the main contributing factors. The available options for replacement of diseased valves are currently limited to mechanical and bioprosthetic valves, while the tissue engineered ones that are under study are currently far from clinical approval. The main problem with the tissue engineered heart valves is their progressive deterioration that leads to regurgitation and/or leaflet thickening a few months after implantation.

On the Mechanics of Transcatheter Aortic Valve Replacement.

Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature.

Coupling of shear-circumferential stress pulses investigation through stress phase angle in FSI models of stenotic artery using experimental data.

Many cardiovascular diseases are closely associated with hemodynamic parameters. The main purpose of this study is mimicking a physiological blood flow in stenotic arteries to provide an understanding of hemodynamic parameters. An experimental setup was designed to produce original pulsatile flow and measure pressure pulse waves through a compliant tube.

Emerging Trends in Heart Valve Engineering: Part IV. Computational Modeling and Experimental Studies.

In this final portion of an extensive review of heart valve engineering, we focus on the computational methods and experimental studies related to heart valves. The discussion begins with a thorough review of computational modeling and the governing equations of fluid and structural interaction. We then move onto multiscale and disease specific modeling.

A Hybrid Tissue-Engineered Heart Valve.

Purpose: This study describes the efforts to develop and test the first hybrid tissue-engineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform tissue layers composed of multiple cell types.

Description: The trileaflet Nitinol mesh scaffolds underwent three-dimensional cell culture with smooth muscle and fibroblast/myofibroblast cells enclosing the mesh, which were finally covered by an endothelial cell layer.

Evaluation: Quantitative and qualitative assays were performed to analyze the microstructure of the tissues.

Load-dependent extracellular matrix organization in atrioventricular heart valves: differences and similarities.

The extracellular matrix of the atrioventricular (AV) valves' leaflets has a key role in the ability of these valves to properly remodel in response to constantly varying physiological loads. While the loading on mitral and tricuspid valves is significantly different, no information is available on how collagen fibers change their orientation in response to these loads. This study delineates the effect of physiological loading on AV valves' leaflets microstructures using Second Harmonic Generation (SHG) microscopy.

Emerging trends in heart valve engineering: Part I. Solutions for future.

As the first section of a multi-part review series, this section provides an overview of the ongoing research and development aimed at fabricating novel heart valve replacements beyond what is currently available for patients. Here we discuss heart valve replacement options that involve a biological component or process for creation, either in vitro or in vivo (tissue-engineered heart valves), and heart valves that are fabricated from polymeric material that are considered permanent inert materials that may suffice for adults where growth is not required. Polymeric materials provide opportunities for cost-effective heart valves that can be more easily manufactured and can be easily integrated with artificial heart and ventricular assist device technologies.

Emerging trends in heart valve engineering: Part II. Novel and standard technologies for aortic valve replacement.

The engineering of technologies for heart valve replacement (i.e., heart valve engineering) is an exciting and evolving field.

Emerging trends in heart valve engineering: Part III. Novel technologies for mitral valve repair and replacement.

In this portion of an extensive review of heart valve engineering, we focus on the current and emerging technologies and techniques to repair or replace the mitral valve. We begin with a discussion of the currently available mechanical and bioprosthetic mitral valves followed by the rationale and limitations of current surgical mitral annuloplasty methods; a discussion of the technique of neo-chordae fabrication and implantation; a review the procedures and clinical results for catheter-based mitral leaflet repair; a highlight of the motivation for and limitations of catheter-based annular reduction therapies; and introduce the early generation devices for catheter-based mitral valve replacement.

The effects of transcatheter valve crimping on pericardial leaflets.

Background: Transcatheter aortic valve replacement has emerged as a promising therapy for treatment of severe aortic stenosis. Although it has been shown that these valves can be safely delivered and implanted, studies of valve longevity are lacking because of the infancy of the technology. Particularly, the effects of stent crimping on the valve's leaflets have not yet been sufficiently investigated.

Characterizing the collagen fiber orientation in pericardial leaflets under mechanical loading conditions.

When implanted inside the body, bioprosthetic heart valve leaflets experience a variety of cyclic mechanical stresses such as shear stress due to blood flow when the valve is open, flexural stress due to cyclic opening and closure of the valve, and tensile stress when the valve is closed. These types of stress lead to a variety of failure modes. In either a natural valve leaflet or a processed pericardial tissue leaflet, collagen fibers reinforce the tissue and provide structural integrity such that the very thin leaflet can stand enormous loads related to cyclic pressure changes.

Inflammatory response assessment of a hybrid tissue-engineered heart valve leaflet.

Despite substantial research in the past few decades, only slight progress has been made toward developing biocompatible, tissue-engineered scaffolds for heart valve leaflets that can withstand the dynamic pressure inside the heart. Recent progress on the development of hybrid scaffolds, which are composed of a thin metal mesh enclosed by multi-layered tissue, appear to be promising for heart valve engineering. This approach retains all the advantages of biological scaffolds while developing a strong extracellular matrix backbone to withstand dynamic loading.

Metal mesh scaffold for tissue engineering of membranes.

Engineering of the membrane-like tissue structures to be utilized in highly dynamic loading environments such as the cardiovascular system has been a challenge in the past decade. Scaffolds are critical components of the engineered tissue membranes and allow them being formed in vitro and remain secure in vivo when implanted in the body. Several approaches have been taken to develop scaffolds for tissue membranes.

Coupled fluid-wall modelling of steady flow in stenotic carotid arteries.

Arterial stenoses may cause critical blood flow and wall conditions leading to clinical complications. In this paper computational models of stenotic carotid arteries are proposed and the vessel wall collapse phenomenon is studied. The models are based on fluid-structure interactions (FSI) between blood and the arterial walls.