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).
By making after-tax contributions to your 401(k), you are not subject to the initial individual 401(k) contribution limits, so you can save much more. You also are not subject to income limits that apply when funding a Roth I.R.A. the usual way, Ms. Brown said.s. Brown offers this example: Assume you are 45, and your employer allows you to make pretax and after-tax contributions to your 401(k). You contribute the maximum pretax amount for the year ($18,000), and receive $7,000 in employer matching contributions (these vary by employer), for a total of $25,000.