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The neutrino event rate in the Borexino scintillator is very low (~ 0.5 events per day per ton) and concentrated in an energy region well below the 2.6 MeV threshold of natural radioactivity. The intrinsic radioactive contaminants in the photomultipliers (PMTs), in the Stainless Steel Sphere, and in other detector components, play special requirements on the system required to contain the scintillator. The liquid scintillator must be shielded from the Stainless Steel Sphere and from the PMTs by a thick barrier of buffer fluid. The fluid barrier, in addition, needs to be segmented in order to contain migration of radon and daughters emanated by the Stainless Steel Sphere and by the PMTs. These requirements were met by designing and building two spherical vessel made of thin nylon film. The inner vessel contains the scintillator, separating it from the surrounding buffer. The buffer region itself is divided into two concentric shells by the second, outer nylon vessel. In addition, the two nylon vessels must satisfy stringent requirements for radioactivity and for mechanical, optical and chemical properties. This paper describes the requirements of the the nylon vessels for the Borexino experiment and offers a brief overview of the construction methods adopted to meet those requirements.

Background: Surgical repair is advocated for flexor tendon lacerations deeper than 70%. Repair can be undertaken with different suturing techniques and using different materials. Different materials used for tendon repair will have a different gliding resistance (GR) at the joint. Previous studies have compared strength of repair and gliding resistance for various braided suture materials and for 100% laceration of flexor tendons. We directly compare the GR of two monofilament sutures when used for a peripheral running suture repair of partially lacerated tendons.

Methods: Sixteen flexor tendons and A2 pulleys were harvested from Turkey feet. They were prepared, partially lacerated to 50% depth, and then repaired with a core suture (modified Kessler technique with 4-0 Ethibond) as well as an additional superficial running suture of either 6-0 Prolene or Nylon (half randomised to each). Gliding resistance was measured for all tendons before and after repair, at different flexion angles (40 and 60 degrees) and for different loads (2N and 4N).

Results: After surgical repair, gliding resistance was increased for all tendons (P < 0.01). The tendons repaired with Prolene had a higher mean gliding resistance than those repaired with Nylon (P = 0.02). Increased flexion angle and load amplified the gliding resistance (both P < 0.01).

Conclusions: 6-0 Nylon was associated with a lower gliding resistance than 6-0 Prolene but the minor differences bare unknown clinical significance.