Turkey has begun efforts to take control of Syria’s Tiyas air base, also known as T4, and is preparing to deploy air defence systems there, sources familiar with the matter told Middle East Eye.

Usually, it is symptomless and may not need treatment. T4 (thyroxine) is a major hormone secreted by your thyroid gland. T3 (triiodothyronine) is the active version of T4. The amount of T4 ...