Is it permissible to combine the Dhuhr and Asr prayers by advancing them, and to combine the Maghrib and Isha prayers by delaying them, due to the nature of a nurse's work, which makes it difficult to perform prayers on time? And is ablution required after touching female patients or shaking hands with non-mahram women at the workplace?

For the prayer to be valid, it must be performed within its prescribed time. Combining prayers is not permissible except for a valid excuse. Among the excuses that permit combining prayers, according to some scholars, is any engagement that allows one to miss Friday prayer and congregational prayer, such as fear for one's life or property, or hardship in one's livelihood. This is based on the Prophet's action, peace and blessings be upon him, when he combined prayers in Medina without fear or rain, "so as not to cause hardship to his Ummah."

Therefore, it is permissible to combine two prayers to alleviate hardship if you are unable to perform each prayer within its designated time and would suffer harm by leaving work.

As for touching a woman's hand, there is a difference of opinion: - Some scholars hold that it nullifies wudu' absolutely. - Others hold that it does not nullify wudu' absolutely, and this is the preferred view, based on the fact that the Prophet, peace and blessings be upon him, kissed some of his wives and then prayed without performing wudu'. - Some scholars differentiate between touching with lust (which nullifies wudu') and without lust (which does not nullify wudu').

However, touching or shaking hands with a non-mahram woman is forbidden except for a necessity like medical treatment.