Combining two runes will give you a random rune of the same tier. Combining 5 runes will give you a random rune of the next highest tier. You cannot combine 5 tier 3 runes at once (as there is no tier 4).
The rune combiner is random. It doesn't matter whether you combine marks, glyphs, seals, or quintessences -- they all work with each other, and the output can be anything.
The idea is that, generally, runes themselves are priced such that it is slightly cheaper to generate a tier 3 runeset from your old runes than by buying the tier 3 runes on their own. For instance, the level 1 +AD rune is 15 ip, while the level 2 +AD rune is 80 ip -- if you bought 5 of the level 1 runes, combined them, and wound up with a level 2 +AD rune, you would have saved yourself IP.
Unfortunately, as mentioned earlier, this process is completely random. If you have tier 1 and 2 runes, by all means, combine them to higher levels; the rune combiner is just a way to possibly recoup the IP you spent on runes you no longer find useful, but it cannot be counted on to give you what you want. You might luck out and combine 2 random runes into a +Dodge quintessence (very expensive!) -- or you might get a mana/5 Mark (with a tertiary stat, and probably not worth the IP cost of your combined runes).
It's very much a gamble, and you don't get anything exclusive from it, so use it if you need to get rid of T1 / T2 runes, and safely ignore it otherwise.
Bonus health means health gained from items / runes / masteries.
At level 18, Shen naturally has 1958 health*, so Ki strike bonus damage is equal to (Total Health - 1958)*.08.
*Shen suffers from a reduction in health due to the Inverse Ninja Law when Akali, Kennen, or both are on his team. This will reduce the base health of all involved by 1 or 2, giving Shen a range of base health from 1956-1958.
Best Answer
I had always assumed that it did, but to make sure, I just tested two cases in a custom game. I did these tests on The Proving Grounds for convenience; the passive gold gain bonus on the map shouldn't affect the results.
In addition, I used Greater Quintessences of Avarice and full points in the Greed mastery for a total of +5 gold per 10 seconds.
I proceeded to purchase a Philosopher's Stone when the in-game clock read 1:00. From here, I did one of two things. In the first case, I cast Whimsy on myself whenever I was alive and ran directly to the Outer Turret. When the in-game clock hit 5:00, I had 1923 gold.
In the second case, after buying the Philosopher's Stone, I sat in my base until 5:00. At that point, I had 1917 gold.
The minor differences can be attributed to the inaccuracy of the client-side game clock.
In short, yes, gold per 10 items still tick while you're dead.