This model is based on the in vitro skin model Skin2 [5] which had been discontinued in October 1996. It was further proposed by industry to apply the model in a tiered strategy to identify those chemicals that are predicted to be likely to be phototoxic in the 3T3-NRU-PT but are negative in vivo [6].
401(k) contribution rules. On a pretax basis, employees can't contribute above certain limits. In 2015, for instance, the limit is $18,000; those 50 and older can make additional catch-up contributions of $6,000.This money is not counted toward income, and all gains are tax-deferred. The limits are the same for Roth 401(k)s, though the contributions do count toward income and all gains are tax-free.But employees can sock away a lot more retirement cash if their company plan offers an after-tax option in a traditional 401(k).he limits are the same for Roth 401(k)s, though the contributions do count toward income and all gains are tax-free. But employees can sock away a lot more retirement cash if their company plan offers an after-tax option in a traditional 401(k).
The only difference is that IRAs have much lower contribution limits than 401(k)s. In 2015, you can put up to $18,000 into a 401(k) (or up to 23,000 if you are age 50 or older) and $5,500 in an IRA (or up to $6,500 with the catch-up contribution).01k Plus Roth IRA. If you are making regular contributions to a 401k and are looking for another way to save even more retirement dollars, a Roth IRA is a great choice. Investors who qualify can contribute to both a 401k and a Roth IRA in the same year, and there are good reasons to do so.