I am a young man and I am a lecturer in a university in Egypt. What is the Islamic ruling on a female student asking me to engage in a scientific discussion with her, given that this is my duty towards my students, whether males or females? This is my job that I should carry out perfectly and duly, and it is impermissible to withhold knowledge.
Note: The faculty in which I am teaching is mechanical engineering which is not of great benefit for female students and were they to work in that field, they would, inevitably, intermix with non-Mahram (marriageable) men; would I be held accountable for that i.e. helping them to work in such non-Islamic work environments for women?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

If the discussions with your female students are confined to the due limits of need while you are sincerely adherent to the due Islamic principles and manners, such as avoiding being with them in seclusion and abstaining from impermissible looks, then such discussions are permissible. However, it is better for you to look for another work place that is free of such impermissible intermixing between men and women. Moreover, you should note that if you fear temptation or fear falling into sin, then you are obliged to eschew such discussions; since what leads to committing the unlawful is itself unlawful.

We would like to draw your attention, dear questioner, to the fact that an educated woman is not obliged to work; and if she did, she should choose a field of work that is free of such impermissible intermixing between men and women. Indeed, it is impermissible for Muslim women to work in places that foster impermissible intermixing between men and women that we see nowadays unless she is in dire need for that job and there are no alternatives available for her. 

Allaah Knows best.