no, not yet :-) but i learned (and i am still learning) pranayama from my teacher studied with Shri O. P. Tiwari. i also took a workshop with gregor maehle who has another aproach on pranayama - he also wrote a book about it. i still have to read it :-) http://chintamaniyoga.com/product/pranayama-breath-yoga/ but i think especially pranayama is a method that should be learned directly from a teacher.