In accordance with at least one aspect of this disclosure, a fuel injector can include an annular body defining a gas fuel inlet therein, and a structure extending radially outward from the annular body and configured to extend into an air circuit. The structure can include a gas channel defined within the structure at least partially along a radial length of the structure. The gas channel is in fluid communication with the gas fuel inlet where the structure meets the annular body. The structure also includes a slot opening defined at least partially along a radial length of the structure and configured to fluidically connect the gas channel and the air circuit to all gas fuel to effuse into the air circuit.