Improving particle collection efficiency of sampling wipes used for trace chemical detection.

Improvement of the particle collection efficiency of sampling wipes is desirable for optimizing the performance of many wipe-based chemical analysis techniques used for trace chemical screening applications. In this note, commercially available Teflon coated fiberglass and calendered Nomex sampling wipes were modified by mechanically scoring the wipe surface to produce topography that promoted enhanced and localized particle collection. Wipe surface modifications improved particle collection efficiency, relative to unmodified wipes, by factors of 3 to 13 depending on sampling conditions, wipe type, and surface sampled.

Mechanisms influencing retrograde flow in the atrioventricular canal during early embryonic cardiogenesis.

Normal development of the heart is regulated, in part, by mechanical influences associated with blood flow during early stages of embryogenesis. Specifically, the potential for retrograde flow at the atrioventricular canal (AVC) is particularly important in valve development. However, the mechanisms causing this retrograde flow have received little attention.

Defecation patterns in infants: a prospective cohort study.

Introduction: Data regarding prevalence and natural history of infant dyschezia, defined by the Rome III criteria as straining and crying for at least 10 min before successful passage of soft stools, are lacking.

Objective: We aimed to investigate prevalence and natural history of infant dyschezia.

Study Design: In 2003, 124 youth healthcare doctors participated in a national study on defecation patterns of infants.

The defecation pattern of healthy term infants up to the age of 3 months.

Background: Defecation problems occur frequently in infants. A clearer insight into the normal defecation pattern is required to gain a better understanding of abnormal defecation.

Aim: To describe the defecation pattern of healthy infants in The Netherlands.