Combine the onion, celery, and oil in a medium nonstick skillet. Stirring constantly, cook over medium heat until softened, about 3 minutes. Add the flour and stir for 1 minute. Add broth and continue to cook and stir until the mixture bubbles and is somewhat thickened, about 2 minutes. Add the chicken, tomato juice, Worcestershire sauce, curry powder and salt. Stirring constantly, cook for 3 minutes more to allow the flavors to blend. Serve over brown rice.