If you're wondering "what the heck is link juice", I did a video explaining what it is and why it's important waaaay back in February 2011 (before I got all fancy and bought a decent mic and AgentMethods branded shirt). Here it is:
And if you're wondering "what the heck is nofollow", here's another video I did a few days later:
I had someone ask me about this same topic yesterday.
Understand, while the idea and concept of link sculpting internally using nofollow in menus and links is a valid concept, it can cause unintended consequences.
I've seen this method cause the entire blog to be removed from google indexing when it was set nofollow, even though there were external links to blog pages if the blog is in a subdirectory, not a subdomain.
If you want to sculpt the blog, do not nofollow it while leaving it in a subdirectory, unless you really know what you are doing OR you are not putting content into your blog that you want found via google search. Otherwise you are potentially removing the blog content from your website, and blogging at that point can have all value removed from it.
I proved this by A B testing the 2 approaches, not by reading what someone else said. On a test of 4 roughly equal blogs, 2 with the blog item nofollowed, it caused all the pages to be deindexed with them sitting in a directory.
Alston's method is a better approach, IMO, if you go look at what he suggested in older posts, if you want to stop the link value of the pages from going into the blog (which may or may not even matter, its very subjective) then putting the blog into a subdomain such as blog.mysite.com, then backlinking your main site in the blog will not cause the blog to be deindexed, and will also not count as added outward facing links.
The approach of doing that sounded interesting to me, until I tested it.