Welcome to the board! Among the stocks you mentioned, PTLA is one I might be interested in buying—depending, of course, on the valuation. I commented on PTLA in the following posts:
Alcobra Ltd., an emerging biopharmaceutical company primarily focused on the development and commercialization of a proprietary drug, MG01CI, to treat Attention Deficit Hyperactivity Disorder, today announced the pricing of its initial public offering of 3,125,000 ordinary shares at an initial public offering price of $8.00 per share. The gross proceeds to Alcobra from the initial public offering are expected to be $25,000,000 [8 x 3.125 = 25, duh]… The ordinary shares are scheduled to begin trading on The NASDAQ Capital Market on May 22, 2013 under the symbol "ADHD."