Tetracycline has been studied extensively in clinical trials, with thousands of people worldwide having been evaluated. In these studies, side effects occurring in a group of people taking the drug were documented and compared to the side effects that occurred in a similar group of people not taking the medicine.
Steel ties are utilised in nearly all sectors of the worldwide railroad systems including heavy-haul, class 1s, regional, shortlines, mining, electrified passenger lines (OHLE) and all manner of industries.
Wires are made of metal (almost always copper or aluminum, for electrical wires) because those are the best conductors. The internal components of switches are also made of metal, for the same reason. The outside parts, that you touch and see, are...