[ScubieNuc]

A title of the Blessed Virgin as mediator of grace. There are two aspects of this mediation. It is certain in Catholic theology that, since Mary gave birth to the Redeemer, who is source of all grace, she is in this way the channel of all graces to mankind.

John 1:17 For the law was given by Moses, [but] grace and truth came by Jesus Christ.

....that since Mary's Assumption into heaven no grace is received by humans without her actual intercessory co-operation.

No Scriptural support for either an "assumption" into heaven (not dying) or any intercessory powers. As with everything else in that post, it is un-Scriptural dogma. You can waste your time and energy believing the "Mary lie", but I wont.

[Salvation]

28. “Hail, full of grace”: literally the Greek text reads “Rejoice!”, obviously referring
to the unique joy over the news which the angel is about to communicate.

“Full of grace”: by this unusual form of greeting the archangel reveals Mary’s
special dignity and honor. The Fathers and Doctors of the Church “taught that
this singular, solemn and unheard-of-greeting showed that all the divine graces
reposed in the Mother of God and that she was adorned with all the gifts of the
Holy Spirit”, which meant that she “was never subject to the curse”, that is, was
preserved from all sin. These words of the archangel in this text constitute one
of the sources which reveal the dogma of Mary’s Immaculate Conception (cf.
Pius IX, “Ineffabilis Deus”; Paul VI, “Creed of the People of God”).