Huaqing Sun

Abstract Objective: To investigate the impact of three endometrial preparation protocols-hormone replacement therapy (HRT), natural cycle (NC), and down-regulation HRT-on pregnancy outcomes in frozen embryo transfer (FET) cycles among patients with a history of intrauterine adhesion (IUA) separation surgery. Method: A retrospective cohort study was conducted to analyze the data from FET cycles at reproductive medicine center from January 2017 to December 2023.

This paper is concerned with a class of singular matrix difference systems of mixed order. By transforming them into the corresponding singular Hamiltonian systems, the limit point and limit circle classification of them is obtained, relationships among the associated maximal, pre-minimal, and minimal subspaces are derived, the singular part of the essential spectrum of such a system is characterized in terms of properties of that of the corresponding Hamiltonian system.

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