A spacer device includes an elongate spacing member extending a longitudinal axis for securing to electrical transmission lines, and has a minimum thickness d.sub.m. At least one thickened portion having a thickness T.sub.t and length d.sub.t is positioned intermediate along the spacing member to form at least two column lengths L.sub.c separated by the at least one thickened portion. Each column length L.sub.c has a portion with the minimum thickness d.sub.m. The thickness T.sub.t and length d.sub.t of the at least one thickened portion can be at least two times the minimum thickness d.sub.m to form at least one end support for the at least two column lengths L.sub.c, such the at least two column lengths L.sub.c behave as separate Euler type columns for producing increased Euler buckling strength with a minimal increase in weight.

A fence standard is provided and includes a shaft and a wire support including an open ended loop. The wire support is molded onto the shaft.

A nanotube-based insulator is provided having thermal insulating properties. The insulator can include a plurality of nanotube sheets stacked on top of one another. Each nanotube sheet can be defined by a plurality of carbon nanotubes. The plurality of carbon nanotubes can be configured so as to decrease normal-to-plane thermal conductivity while permitting in-plane thermal conductivity. A plurality of spacers can be situated between adjacent nanotube sheets so as to reduce interlayer contact between the nanotubes in each sheet. The plurality of spacers can be ceramic or alumina dots or provided by texturing the nanotube sheets.

An implantable medical lead has a torsional stiffness and is rotationally coupled to a stylet. Applying rotation directly to the lead in turn causes rotation of the stylet. Where the stylet has a bent tip for purposes of steering the lead, the rotation applied to the lead rotates the bent tip so that the lead can be steered by rotating the lead rather than rotating a hub of the stylet. The rotational coupling may be achieved through one or more features provided for the lead and/or the stylet, such as a feature within a lumen of the lead that mates to a feature along the stylet or a feature of the stylet hub that engages the proximal end of the lead. The torsional stillness of the lead may be provided by adding a feature within the lead body, such as a braided metal wire or an overlapping foil.

A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter be forward-assembled.

A hydraulic joint is disclosed. The hydraulic joint includes a tube, a hydraulic fitting, and a tip seal. The hydraulic fitting may be positioned around the tube. The hydraulic fitting may include a first open end for receiving the tube. The tip seal may be configured to define an opening that allows for the passage of leaks. The tip seal may be positioned on the hydraulic fitting adjacent the open end and forming a mechanical barrier between the fitting and the tube.

A shield located within an implantable medical lead may be terminated in various ways. The shield may be terminated by butt, scarf, lap, or other joints between insulation layers surrounding the lead and an insulation extension. For lap joints, a portion of an outer insulation layer may be removed and a replacement outer insulation layer is positioned in place of the removed outer insulation layer, where the replacement layer extends beyond an inner insulation layer and the shield. The replacement layer may also lap onto a portion of the insulation extension. Barbs may be located between the replacement layer and the inner insulation layer or the insulation extension. The shield wires have ends at the termination point that may be folded over individually or may be capped with a ring located within one of the insulation layers of the jacket.

Implantable medical leads include a shield that is guarded at a termination by having a first portion and a second portion of the shield, where the first portion is between a termination of the shield at the second portion and an inner insulation layer that surrounds the filars. The first portion may reduce the coupling of RF energy from the termination of the shield at the second portion to the filars. The first and second portions may be part of a continuous shield, where the first and second portions are separated by an inversion of the shield. The first and second portions may instead be separate pieces. The first portion may be noninverted and reside between the termination at the second portion and the inner layers, or the first portion may be inverted to create first and second sub-portions. The shield termination at the second portion is between the first and second sub-portions.

A shield located within an implantable medical lead may be terminated in various ways. The shield may be terminated by butt, scarf, lap, or other joints between insulation layers surrounding the lead and an insulation extension. For lap joints, a portion of an outer insulation layer may be removed and a replacement outer insulation layer is positioned in place of the removed outer insulation layer, where the replacement layer extends beyond an inner insulation layer and the shield. The replacement layer may also lap onto a portion of the insulation extension. Barbs may be located between the replacement layer and the inner insulation layer or the insulation extension. The shield wires have ends at the termination point that may be folded over individually or may be capped with a ring located within one of the insulation layers of the jacket.

Implantable medical leads and implantable lead extensions include a shield. The implantable medical lead is coupled to the implantable lead extension. Stimulation electrodes of the implantable medical lead contact stimulation connectors within a housing of the implantable extension to establish a conductive pathway for stimulation signals from filars of the implantable extension to filars of the implantable medical lead. Continuity is established between the shield of the implantable medical lead and the implantable extension by providing a radio frequency conductive pathway within the housing. The radio frequency conductive pathway extends from a shield of the implantable extension to a shield connector that contacts a shield electrode of the implantable medical lead. The radio frequency conductive pathway may have various forms such as a jumper wire or an extension of the shield within the implantable extension.