Effect of Manufacturing Conditions on Structural and Handling Properties of Braided Polyamide Suture
Suture performances include handling characteristics and knot mechanical properties. These performances depend mainly on frictional, flexural, and compressive forces. The interaction between these forces developed inside the suture knot governs the displacement mode and the deformability of the suture yarn inside the knot. In the present work, we studied the effect of manufacturing conditions on structural properties and handling characteristics. Obtained results show that manufacturing parameters have significant impact on slipperiness, flexibility, and compressibility. Consequently, suture performances widely depend on manufacturing parameters. We show that after a hot stretch step, suture structure becomes more uniform and compact. Furthermore, after this treatment, lateral deformation, friction force, and bending rigidity are reduced and knot performances are improved.
Analysis of Polymeric Braided Tubular Structures Intended for Medical Applications
In this study, monofilament tubular braided structures were fabricated and their performances were analyzed. The braided tubes are in three-dimensional form, made of polyester monofilaments intended for use in medical applications. This type of structure, called a stent, is used to open clogged arteries and veins by exerting radial forces. The radial force of a braided tube basically depends on three variables: braid angle, helical length, and braid diameter. The mandrel diameter influences the axial and radial forces obtained from the braid tube. In order to assure a stable structure, the braided fabrics were heat-set. Analysis of variances showed that heat-setting temperatures and heat-setting times of braided fabrics exhibited no significant effects in the range in which the tests were performed.
The incidence of dead and dying fish in the Moray Firth, September 1963
Dead and dying fish were reported from the Moray Firth during a period of 15 days in September 1963. The initial mortalities were in the inner Firth, but they later spread outwards, especially eastwards along the southern shores of the Firth. Mass mortalities of the lugworm (Arenicola marina) also occurred in Scottish waters in 1962 and 1963, and at Balintorein Easter Ross fish and lugworm mortalities were contemporary.