Abstract: A welding device has a central unit and a welding torch unit, which can be connected to the central unit. The central unit includes at least one welding current source for providing electric current needed to operate the welding torch unit and includes a control unit. The welding torch unit includes at least a first welding torch with a first welding wire and a second welding torch with a second welding wire. The control unit is configured to carry out a starting process in such a way that firstly a first arc ignition takes place at one of the two welding torches and after a waiting time since the first arc ignition has passed, a second arc ignition takes place at the other of the two welding torches, which until then was not ignited.

Abstract: Polypeptides capable of binding human IL-13 and/or of binding human IL-4 in the presence of IL-4 R.alpha. can be used in medicine, in diagnosis and in screening for agonists/antagonists of IL-13/IL-4. One such polypeptide is shown in FIG. 1.