重庆市副市长、市公安局局长张安疆同志因病医治无效不幸离世

Used to express causation where 因 introduces the cause and 而 connects to the result. Common in formal writing to show 'because of X, therefore Y'.

经 means 'after undergoing/experiencing' and 无效 means 'ineffective/unsuccessful'. Together they express that despite efforts, the desired result was not achieved.

于 is a formal preposition equivalent to 在, used primarily in written Chinese to indicate time or location. Much more formal than 在.

A respectful, formal expression used exclusively to state someone's age at the time of death. Literally means 'enjoyed years'. Only used in obituaries and formal death announcements.

同志 (comrade) is placed after a person's name as a formal title, especially in government and official contexts. Shows respect and formality in mainland China's official discourse.