Characterization of full-length recombinant human Proteoglycan 4 as an ocular surface boundary lubricant.

Proteoglycan 4 (PRG4, or lubricin) is a lubricating mucin-like glycoprotein recently discovered at the ocular surface, where it functions as a boundary lubricant and appears to play a protective role. Recent technological advances have enabled abundant expression of full-length recombinant human PRG4 (rhPRG4). The objectives of this study were to 1) biochemically characterize the gross structure and glycosylations of full-length rhPRG4, and 2) assess the ocular surface boundary lubricating ability of rhPRG4 at both human cornea-eyelid and human cornea-polydimethylsiloxane (PDMS) biointerfaces.

Expert surgeon's quiet eye and slowing down: expertise differences in performance and quiet eye duration during identification and dissection of the recurrent laryngeal nerve.

Background: Long quiet eye (QE) duration is central to expertise in sports, while cognitive "slowing down" has been identified as a perceptual skill possessed by skilled surgeons. Eye-tracking evidence is lacking about the relationship of QE duration to slowing down in surgeons. The aim of this study was to examine QE duration, hand movement time (MT), fixation location, and fixation duration in highly experienced (HE) and less experienced (LE) surgeons.

Transcription, translation, and function of lubricin, a boundary lubricant, at the ocular surface.

Importance: Lubricin may be an important barrier to the development of corneal and conjunctival epitheliopathies that may occur in dry eye disease and contact lens wear.

Objective: To test the hypotheses that lubricin (ie, proteoglycan 4 [PRG4 ]), a boundary lubricant, is produced by ocular surface epithelia and acts to protect the cornea and conjunctiva against significant shear forces generated during an eyelid blink and that lubricin deficiency increases shear stress on the ocular surface and promotes corneal damage.

Design, Setting, And Participants: Human, porcine, and mouse tissues and cells were processed for molecular biological, immunohistochemical, and tribological studies, and wild-type and PRG4 knockout mice were evaluated for corneal damage.

Dose-dependent and synergistic effects of proteoglycan 4 on boundary lubrication at a human cornea-polydimethylsiloxane biointerface.

Objectives: Proteoglycan 4 (PRG4), also known as lubricin, is a boundary lubricating mucin-like glycoprotein present on several tissue surfaces in the body. The objectives of this study were to (1) implement and characterize an in vitro boundary lubrication test at a human cornea-polydimethylsiloxane (PDMS) biointerface and (2) determine the dose-dependent and synergistic effects of PRG4, with hyaluronan (HA), on ocular surface boundary lubrication using this test.

Methods: Human corneas and model PDMS material were articulated against each other, at effective sliding velocities v(eff) between 0.

Influence of virtual reality training on the roadside crossing judgments of child pedestrians.

The roadside crossing judgments of children aged 7, 9, and 11 years were assessed relative to controls before and after training with a computer-simulated traffic environment. Trained children crossed more quickly, and their estimated crossing times became better aligned with actual crossing times. They crossed more promptly, missed fewer safe opportunities to cross, accepted smaller traffic gaps without increasing the number of risky crossings, and showed better conceptual understanding of the factors to be considered when making crossing judgments.

The effects of adult guidance and peer discussion on the development of children's representations: evidence from the training of pedestrian skills.

It was hypothesized that practical training is effective in improving children's pedestrian skills because adult scaffolding and peer discussion during training specifically promote E3 level representation (linguistically-encoded, experientially-grounded, generalizable knowledge), as defined by Karmiloff-Smith's (1992) representational redescription (RR) model. Two studies were conducted to examine in detail the impact of this social input in the context of simulation-based training in roadside search skills. A group of 5-8-year-olds were pre-tested on ability to detect relevant road-crossing features.