Safety of vaginal breech delivery following an unsuccessful external cephalic version: a comparative study.

Objective: To determine whether patients undergoing a trial of labor with a breech presentation following a failed attempt of external cephalic version (ECV) are at increased risk of adverse maternal and neonatal outcomes.

Methods: This retrospective cohort study was conducted at a single university-affiliated medical center. The study group comprised women with singleton pregnancies at term, categorized into three groups: those who underwent a failed external cephalic version (ECV) and subsequently attempted a trial of breech delivery (Breech-failed-ECV group), those who attempted an assisted vaginal breech delivery without a prior ECV attempt (Breech-no-ECV group), and those with vertex presentation following a successful ECV (Vertex-ECV).

Addressing a systematic error correcting for free and mixed convection when measuring mean radiant temperature with globe thermometers.

It is widely accepted that most people spend the majority of their lives indoors. Most individuals do not realize that while indoors, roughly half of heat exchange affecting their thermal comfort is in the form of thermal infrared radiation. We show that while researchers have been aware of its thermal comfort significance over the past century, systemic error has crept into the most common evaluation techniques, preventing adequate characterization of the radiant environment.

A fresh (air) look at ventilation for COVID-19: Estimating the global energy savings potential of coupling natural ventilation with novel radiant cooling strategies.

Radiant cooling-assisted natural ventilation is an innovative technical approach that combines new radiant cooling technology with natural ventilation to increase fresh air delivery into buildings year-round with minimal energy cost and improvment of air quality. Currently, the standard paradigm for HVAC (heating, ventilation and air conditioning) is based on central air systems that tie the delivery of heating and cooling to the delivery of fresh air. To prevent heat loss, the delivery of fresh air must be tightly controlled and is often limited through recirculation of already heated or cooled air.

Spatial analysis of the impact of UVGI technology in occupied rooms using ray-tracing simulation.

The use of Ultraviolet Germicidal Irradiation (UVGI) devices in the upper zones of occupied buildings has gained increased attention as one of the most effective mitigation technologies for the transmission of COVID-19. To ensure safe and effective use of upper-room UVGI, it is necessary to devise a simulation technique that enables engineers, designers, and users to explore the impact of different design and operational parameters. We have developed a simulation technique for calculating UV-C fluence rate within the volume of the upper zone and planar irradiance in the lower occupied zone.

Membrane-assisted radiant cooling for expanding thermal comfort zones globally without air conditioning.

We present results of a radiant cooling system that made the hot and humid tropical climate of Singapore feel cool and comfortable. Thermal radiation exchange between occupants and surfaces in the built environment can augment thermal comfort. The lack of widespread commercial adoption of radiant-cooling technologies is due to two widely held views: 1) The low temperature required for radiant cooling in humid environments will form condensation; and 2) cold surfaces will still cool adjacent air via convection, limiting overall radiant-cooling effectiveness.