Possible role of apoptosis in Alzheimer's disease.

A coupling for thin-walled tubing, such as aircraft fuel lines, wherein a bearing ridge and O-Ring groove are preformed at the open tube end and wherein a coupling body, retaining nut and anchor ring are engageable over said bearing ridge and groove, the anchor ring being reversibly visible for inspection and in the form of an expansible doublesided buttress disengageably installed over the tube and combined with the retaining nut to abutt the said bearing ridge and related to the coupling body so as to have anti-extrusion features with respect to the O-Ring seal subjected to internal fluid pressures.