Dimethicone, also known as polydimethylsiloxane, is a silicon-based polymer that is a man-made synthetic molecule made up of repeating units called monomers. Silicon is the second most abundant element in the Earth's crust after oxygen, and silicon dioxide is also known as sand, commonly found on beaches and shores.
In regards to a job, a refusal letter is written when a company offers a position to an individual who must refuse due to his or her circumstances, such as already having accepted another offer, or simply a lack of interest in this particular job.
A letter of credit is a formal document, which a bank issues on behalf of the buyer to the seller. The document states that the bank will honour the drafts drawn on the buyer, for the goods supplied to him, provided the conditions written on the document are satisfied by the supplier (seller).